8th grade
Laboratory work No. 1 “Study of the microscopic structure of tissues”
Target: teach how to identify different types of tissues on ready-made micropreparations.
Equipment: micropreparations of epithelial, connective, muscle and nervous tissue.
Progress:
1. Examine the sections of epithelial tissue on the preparation. Draw an epithelial cell.
2. Determine the type of connective tissue (bone, cartilage, loose connective tissue). Draw a cell.
3. Determine the type of muscle tissue (smooth, striated). Draw a cell.
4. Examine the neuron in the “Structure of Nervous Tissue” specimen. Draw a neuron and label all parts.
5. Find out whether the tissue you are viewing is connective or epithelial.
6. Fill out the table:
| Fabric name | Structural features | Function performed |
Laboratory work No. 2 “Recognition of human organs and organ systems on tables.”
Target: Teach to recognize human organs and organ systems in tables, pictures, models.
Equipment: tables, drawings, models.
Progress:
Look at the tables for the digestive system and the organs of the digestive system.
Look at the tables for the circulatory system and the organs of the circulatory system. On models and tables, examine the heart and its parts.
Look at the tables and models - the musculoskeletal system, parts of the skeleton.
Consider the respiratory system and organs of the respiratory system in the tables.
Look at the tables on the nervous system: nerves, spinal cord and brain.
Fill the table:
| Organ system name | Major organs | |
Laboratory work No. 3 “Study of the human brain (using dummies).”
Target: get to know the parts of the brain and their functions.
Equipment: brain models.
Progress:
1. Find the parts of the brain on the models: anterior, middle, intermediate, oblongata, cerebellum, cerebral hemispheres.
2. Medulla.
Using the handle of a spoon, touch the back surface of the tongue. A swallowing reflex occurs involuntarily.
The subject makes several swallowing movements in a row. When there is nothing left in his mouth, the swallowing reflex will not appear.
The subject takes 2-3 quick and deep breaths in and out. After this, his breathing stops for some time.
What functions of the medulla oblongata were revealed during the experiment?
What other functions of this part of the brain are you familiar with?
3. Midbrain.
Students are offered tasks (for example, to read a short book), and as soon as all the subjects have started reading, the teacher suddenly and quite loudly knocks on the table with a pencil. At this time, most students will stop reading and involuntarily turn their heads towards the sound (indicative reflex).
The subject looks at the lit lamp. Sees one light source. Now he gently presses on one of the eyeballs and looks again at the light source. The object begins to double, two light bulbs are visible. This happened because the correct setting, controlled by the midbrain, was disrupted.
The subject closes his eyes, extends his right hand forward with the index finger extended, the rest clenched into a fist. After this, touch your nose with the tip of your index finger.
What functions of the midbrain were established using this experiment?
4. Diencephalon.
The teacher invites students to mind their own business, and he himself gives a loud command “freeze!” The subjects freeze in different positions (diencephalon reflex).
5. Fill out the table:
| Name of brain section | |
Laboratory work No. 4 “Study of changes in pupil size”
Target: develop a conditioned vegetative pupillary reflex in a person to a bell; become familiar with the braking process.
Equipment: alarm clock, dark thick sheet of paper (it’s better to take a New Year’s mask with sealed eye holes for this).
Work is carried out in good lighting.
Progress.
The experimenter sets the alarm clock, which should ring for approximately 10-12 seconds. At this moment, he observes the state of the subject’s pupil. If the pupil does not dilate to the signal. You can move on to developing a conditioned reflex.
The experimenter turns on the bell again. At this time, the subject closes his eyes tightly with a dark mask. When the signal stops, he opens his eyes. At this moment, the experimenter observes the size of the subject’s pupils (they should dilate). The experiment is carried out 10 times in combination with darkening (repetitions must be done without breaks). At the 11th time, the experimenter turns on the bell, but the subject does not put on a dark mask, and the experimenter observes the conditioned reflex dilation of the pupil.
Fill out the table “Results of the development of the pupillary reflex”
| Serial number of the stimulus | Conditioned stimulus (bell) | Unconditioned stimulus (light) | Unconditional response | Conditioned response |
Laboratory work No. 5 "Study of the appearance of individual bones."
Target: study the features of the external structure of human bones.
Equipment: human bone models
Progress:
Task 1. Write a description of the given bone. When writing a description, you must indicate:
Dice name
Belonging to one of the bone classification groups (tubular, spongy, mixed, flat, pneumatic)
Belonging to one of the sections of the skeleton
List the bones with which it articulates
Bone structure.
For example:
Flat bone
Upper limb belt
Connected to the clavicle and head of the humerus
It is a flat, triangle-shaped bone.
Laboratory work No. 6 "Identification of the influence of statistical and dynamic work on muscle fatigue."
Target: identify the dependence of the onset of fatigue on the type of work performed.
Equipment: a dumbbell weighing 5 kg or a briefcase with textbooks, a watch with a second hand.
Progress:
1. Static muscle work.
The subject takes a dumbbell or briefcase in one hand and stands facing the class so that his back does not touch the wall. He moves his hand with the load horizontally to the side along the board. A chalk line marks the level at which the hand with the load is located. The stopwatch records the time the arm drops due to fatigue.
2. Dynamic muscle work.
The subject raises and lowers the load to the height of the previously made chalk line. The experiment is carried out 30 seconds longer than the previous one.
Laboratory work No. 7 “Measuring the mass and height of your body »
Target: learn to measure your height and weight, become familiar with the location of individual bones and muscles.
Equipment: scales, measuring tape.
Progress:
Task 1. Take the following measurements:
Using a scale, measure your weight.
Measure your height.
Write down the data in your notebook
Height_____________
Weight______________
Calculate your ideal weight using Brock's formula. Compare with your actual weight. Draw the appropriate conclusion.
Ideal weight according to Broca's formula is calculated as follows:
Height (cm) minus 110
Your result________
Differences between actual weight and ideal weight by 10% or less are considered normal.
Differences from 10% to 20% are considered above normal.
Differences of 20% or more are significant differences from the norm.
Write your conclusion in your notebook.
Task 2.
Look at the picture on page 101 “Human Skeleton” and the picture on page 120 “Muscles of the Torso and Limbs”. Find the bones of the upper limb and the muscles that provide movement in the shoulder joint.
Finish the sentence. “The most powerful muscle of the shoulder joint is ………….., it is attached on one side to ……… and to ………, and on the other side to the humerus. When this muscle contracts, the hand……….”
Bend your elbow and feel the biceps muscle on the inside of your shoulder. Then straighten your arm and find the triceps muscle.
Write down the conclusion: “The biceps muscle is attached at one end to ………., and the other to ………….. The biceps muscle flexes the arm at the ………… joint. The triceps muscle is located on ………. side of the shoulder. Three tendons extend from its upper end: one is attached to …………, and the other two to ………. bones. When this muscle contracts, the hand……………”.
Make a series of different movements with your fingers.
Conclusion: “The movement of human fingers occurs due to the contraction and relaxation of many muscles located on ………….., ………… and the metacarpus.”
Pay attention to the structure of the bones of the lower extremities. Find them and the muscles attached to them in the pictures. Record the conclusion.
“The sartorius muscle has the shape of a narrow, long band that crosses diagonally across the front of the thigh. It starts from ………..and attaches to …………… When contracting, the sartorius bends ………. And …………
Locate the quadriceps muscle on the front of your thigh. “The quadriceps femoris muscle starts from ………… and is attached by one common tendon to the large ………… bone. The muscle is an extensor………… and is involved in flexion………"
Locate the gastrocnemius muscle on the back of your shin. “The calf muscle is attached at one end to ………. bones, and others to …………… The calf muscle flexes ………… and lifts ……….. from the ground.”
Laboratory work No. 8 “Study of the microscopic structure of blood.”
Target: find out the structural features of human and frog blood.
Equipment: ready-made microslides.
Progress:
Consider human and frog blood preparations. Pay attention to the shape of the red blood cells when viewing them from above and from the side. Is it the same in humans and frogs?
Why are human red blood cells slightly translucent in the middle part?
Sketch 2-3 red blood cells from each preparation and 1 human leukocyte on the same scale.
Find similarities between red blood cells.
Compare red blood cells and leukocytes in human blood. What is their difference?
Whose blood of a person or a frog will carry more oxygen per unit time and why?
Laboratory work No. 9 “Counting pulse beats at rest and during physical activity, measuring blood pressure”
Target: practice the technique of measuring blood pressure, develop the skill of counting pulse in different conditions.
Equipment: tonometer and endoscope (for listening to tones), stopwatch.
Progress
Exercise 1. Blood pressure measurement.
1. The tonometer cuff is wrapped around the subject’s left shoulder (after exposing the left arm).
2. A phonendoscope is installed in the area of the ulnar fossa. The subject's left arm is turned out and the palm of his right hand is placed under his elbow.
3. The experimenter pumps air into the cuff to 150-170 mm Hg.
4. The experimenter slowly releases air from the cuff and listens to the tones. At the moment of the first sound signal, the systolic pressure value appears on the instrument scale (since at this moment only during the systole of the left ventricle blood is pushed through the compressed section of the artery)
5. The experimenter records the pressure value.
6. Gradually the sound signal will weaken and disappear. At this moment, the diastolic pressure value can be seen on the scale.
7. The experimenter records the diastolic pressure. To obtain more accurate results, the experiment should be repeated several times.
8. Compare the data obtained in the experiment with the average tabular data on blood pressure for your age. Draw a conclusion.
9. Calculate the values of pulse pressure (PP), mean arterial pressure (MAP) and own blood pressure (BPsist and BPdiast). Known. That the normal pulse pressure in a healthy person is approximately 45 mm. Art.
Arterial (BP):BPsist.=1.7 age+83
BPdiast.=1.6age+42
Pulse (PP): PP = BPsyst. - BPdiast.
Mean arterial blood pressure (MAP):
ADsr. = (ADsyst.-ADdiast)\3+ADdiast.
Evaluation of results
Compare the calculated data obtained in the experiment with the data presented in the table.
Average maximum and minimum blood pressure values for students.
| Age, years | Boys | |
Answer the questions: what danger does constantly high blood pressure pose to humans? Which vessels in our body have the lowest pressure and why?
Task 2. Pulse counting.
1. Introducing students to the palpation method.
Pulse determination is based on the palpation method. It involves palpating and counting pulse waves. It is usually customary to determine the pulse at the radial artery at the base of the thumb. At rest, the pulse can be counted at 10-15-30- and 60-second intervals. After physical activity, the pulse is counted at 10-second intervals.
2. Calculate your own pulse in different physical states:
After 10 squats.
3. Fill out the table:
| Physical state | Heart rate in different physical states |
| In a sitting position | |
| after 10 squats |
4. Evaluation of results.
The normal heart rate at the age of 15-20 years is 60-90 beats per minute. In a lying position, the pulse is on average 10 beats per minute less than in a standing position. Women's heart rate is 7-10 beats per minute faster than men of the same age. A pulse rate during work in the range of 100-130 beats per minute indicates a low intensity of the load. A frequency of 130-150 beats per minute characterizes a medium-intensity load. A frequency of 150-170 beats per minute characterizes the load above average intensity. A frequency of 170-200 beats per minute is typical for maximum load.
5. Draw conclusions about pulse rate and heart contractions.
Laboratory work No. 10 “Studying techniques for stopping capillary, arterial and venous bleeding”
Goal of the work: learn practically how to provide first aid for bleeding
Equipment: Dressing materials, a tourniquet, a piece of cloth, a pencil, a notepad, iodine, Vaseline or cream (an antiseptic ointment simulator), cotton wool, scissors.
Progress:
Capillary bleeding.
Treat the edges of the conditioned wound with iodine
Cut a square piece of bandage and fold it into quarters. Apply ointment to a folded bandage and apply it to the wound, put cotton wool on top and make a bandage.
Arterial bleeding
1. Find on yourself typical places for pressing the arteries to the bones in order to stop bleeding.
2. Determine the location of the tourniquet for a conditional injury.
3. Place a piece of fabric under the tourniquet, make 2-3 turns with the tourniquet until the pulsation can no longer be felt.
Attention! Loosen the tourniquet immediately!
4. Include a note indicating the time the tourniquet was applied.
Remember the rules for applying a tourniquet: the tourniquet is applied for 1. – 2 hours in the warm season and for 1 hour in the cold season. A note is placed under the tourniquet indicating the date and time the tourniquet was applied.
Venous bleeding.
Determine the conditional location of the injury (on the limb).
Raise the limb upward to prevent a large flow of blood to the injury site.
If venous bleeding occurs, apply a pressure bandage.
If a large venous vessel is damaged, apply a tourniquet.
Attention: in case of arterial and venous bleeding, after providing first aid, the victim must be taken to the hospital.
As you progress, fill out the table:
| Type of bleeding | Signs of bleeding | First aid |
| Capillary bleeding | ||
| Arterial bleeding | ||
| Venous bleeding |
Laboratory work No. 11 “Determination of respiratory rate”
Target: Determination of respiratory rate in various physical conditions, establish the effect of holding your breath on breathing frequency.
Equipment: stopwatch.
Progress:
Count the number of breathing movements while sitting.
Count the number of breathing movements while standing.
Count the number of breathing movements after 10 squats.
Enter the results into the table:
| Physical state | Number of breathing movements |
| In a sitting position | |
| After 10 squats |
Conclusion: _______________________________________________________________________________________________________________________________________________________________________________________________.
Determine the time you hold your breath while inhaling while sitting. The subject breathes calmly for 3-4 minutes in a sitting position, and then, on command, after a normal exhalation, takes a deep breath and holds his breath as long as he can, while pinching his nose. The experimenter, using a stopwatch, determines the time from the moment the breath is held until the moment it resumes. The result is recorded (stage 1)
Do 20 squats in 30 seconds and again determine the time you hold your breath while inhaling (stage 2)
Rest for exactly a minute and repeat step 5 (stage 3)
Enter the results into the table
| Stages of work | |
| Health status | 1st stage of work | 2nd stage of work | 3rd stage of work |
| Healthy, trained | More than 50% of the 1st stage | More than 1005 1st stage |
|
| Healthy, untrained | 30-50% of the 1st stage | 70-100% of the 1st stage |
|
| Hidden circulatory failure | Less than 30% of the 1st stage | Less than 70% of the 1st stage |
Laboratory work No. 12 “Studying the effect of gastric juice on proteins, the effect of saliva on starch”
Target: Make sure that there are enzymes in saliva that can break down starch, and in gastric juice there are enzymes that can break down proteins.
Equipment: a piece of starched dry bandage the size of your palm, a Petri dish or saucer with a weak iodine solution, cotton swabs, chicken egg white, gastric juice or pepsin solution.
Progress.
Soak a cotton swab with saliva and write a letter in the middle of a piece of starched bandage.
Squeeze the gauze between your palms for 2-3 minutes, and then dip it in the iodine solution.
Observe how a piece of gauze is colored. Explain the results of the experiment.
Reporting form.
Write down the results of your work in your notebook:
The purpose of the experience, the progress of the work, the result of the work, the conclusion from the experience.
Proteins are broken down under the influence of the enzyme pepsin contained in gastric juice. However, pepsin acts at a certain temperature and in an acidic environment. To prepare an egg white solution, separate the whites of raw chicken eggs from the yolks. Add water to the whites in a 1:1 ratio and mix the resulting solution thoroughly. To make the protein dissolve better, you need to add half a teaspoon of table salt to the mixture. Then the resulting solution should be filtered through a thin layer of cotton wool and boiled. The resulting white protein flakes after cooling are suitable for studying the enzymatic action of gastric juice.
Progress
Number the tubes (No. 1-4). Pour 1 ml into each of them. gastric juice (pepsin solution)
Heat test tube No. 2 with gastric juice to boiling and cool.
Add a 0.5% solution of sodium caustic alkali (3-5 drops) to test tube No. 3. Add a small amount of prepared protein to all test tubes.
Shake the test tubes several times and place: No. 1-3 - in a water bath (37 degrees C); No. 4 – in a glass with ice. Shake the contents of the tubes every 8-10 minutes.
4. After 30 minutes, note what changes have occurred in the protein.
Reporting form
5. Describe the experiments done in your notebook. Record the observation results in the table.
The effect of gastric juice on proteins
| Tube number | Contents of the tube | Temperature | results |
| Protein + 1 ml gastric juice | The content has become transparent |
||
6. Draw conclusions about the effect of gastric juice on protein.
Laboratory work No. 13 “Determination of healthy nutrition standards”
Target: introduce students to the body’s energy balance, teach them to calculate the minimum daily expenditure close to the basal metabolic rate.
Progress
Determine the estimated value of your basal metabolic rate.
At rest, for every 1 kg of mass, boys spend 150 kJ, girls - 130 kJ per day. By multiplying this value by body weight, each student determines the estimated value of his basal metabolic rate.
For an adult, the basal metabolic rate is lower, on average it is 96.6 kJ per 1 kg of weight.
During work, the intensity of energy costs increases significantly:
When working in class by 20-50%;
In laboratory classes - by 75-125%;
When walking – by 150-175%;
When running, climbing stairs - 300-400% of the main volume.
2. Calculate the additional energy costs for doing the work and fill out the table.
Determination of additional energy costs
| Activities | young men | Additional energy costs (kJ per 1 hour per kg body weight) girls | Body weight (kg) | Time watch ) | Amount of additional energy consumption (kJ) |
| Lessons and preparation for them | |||||
| Playing, working in school workshops | |||||
| Running, sports, heavy physical work |
Determination of the total amount of daily energy costs (basic metabolic rate + additional energy costs).
Diet preparation.
Solution to the problem: calculate the daily food ration for a teenager whose weight is 50 kg and who spent 12,000 kJ per day.
When compiling a diet, you should proceed from the following data:
For every 1 kg of body weight, a teenager needs 2 g of protein and 2 g of fat per day.
The missing energy supply is replenished with carbohydrates.
The energy value of 1 g of protein is 17 kJ, 1 g of fat is 39 kJ, 1 g of carbohydrates is 17 kJ.
Solution progress:
The daily protein requirement is 2g x 50 = 100g, which is 100 x 17 kJ = 1700 kJ
Due to fats, the body can get 100 x 39 kJ = 3900 kJ;
Thus, fats and proteins together compensate for 5600 kJ of energy costs. The rest of the costs should be replenished from carbohydrates: 12000 kJ-5600 kJ = 6400 kJ, i.e. In the diet, given that 1 g of carbohydrates provides 17 kJ, 6400:17 = 377 g of carbohydrates should be included.
Based on the fact that the calorie content of breakfast should be equal to 25% of the daily diet, lunch - 505, afternoon snack - 15%, dinner - 105, the daily nutrient consumption is (see table):
Composition of proteins, fats and carbohydrates in the daily diet
| Nutrients | |||||
| Carbohydrates(g) |
Creating a sample menu is homework.
When creating a menu, you must use the table “Chemical composition and calorie content of food products.”
Sample breakfast menu
| Products | Carbohydrates(g) | Calorie content(kJ) |
||
| Mashed potatoes (150g) | ||||
| Beef liver(75g) | ||||
| Black bread (100g) | ||||
| Candies “Mishka” (30g) | ||||
| Tea without sugar | ||||
Laboratory work No. 14 “Analysis and assessment of the environment, risk factors for human health”
Target: study the influence of environmental factors and risk factors on human health.
Progress
Task 1. Based on existing knowledge of biology and geography, draw up a diagram of environmental factors.
Favorable unfavorable:
Task 2. Assess their impact on human health.
Summarize risk factors using knowledge of topics studied.
Task 3. Conclude what is necessary to improve health.
Task 4. Make a plan on the issue “Compliance with sanitary and hygienic standards and rules of a healthy lifestyle.”
9th grade
Laboratory work No. 1
“Identification of organisms’ adaptation to their environment (using specific examples)”
Target: to develop the ability to determine the habitat of organisms and identify fitness traits.
Equipment: indoor plants or herbarium specimens of plants: light-loving, shade-tolerant, xerophytes, hydrophytes, cards depicting animals living in different habitats.
Progress.
Examine the herbarium or living specimen offered to you and determine its habitat.
Using a textbook and additional literature, determine the structural features of the plant and its adaptation to its environment.
Look at the cards with pictures of animals offered to you, determine its habitat.
Using a textbook and additional literature, determine the structural features of the animal and its adaptability to its environment.
Fill the table.
| Defined signs | Animals | Plant |
| Habitat | ||
| Traits of adaptation to the environment | ||
| Relative nature of fitness |
Exercise. Explain the mechanism of occurrence of one of the identified adaptations in the studied organisms.
Draw a conclusion - what determines the appearance of various adaptations in living organisms?
Laboratory work No. 2
“Identification of variability in organisms, species criteria, results of artificial selection on varieties of cultivated plants”
Target: studying variability, consolidating knowledge about the morphological criteria of a species, learning to describe the morphological characteristics of plants, studying the result of artificial selection using the example of wheat varieties.
Equipment: herbarium specimens of plants of the same species growing in different conditions, indoor plants or herbariums of plants of different species, herbarium specimens of various varieties of wheat.
Progress:
Consider plants of the same species that grow in wet and dry conditions; in the meadow and in the mountains. Draw a conclusion.
Consider two types of plants and write down their characteristics in the table.
| Characteristics studied | Plant No. 1 (name of plant species) | Plant No. 2 (name of plant species) |
| Simple, complex Venation Leaf arrangement | ||
| Herbaceous, woody Erect, curly, etc. | ||
| Flower (formula | ||
| 4. Inflorescence (type) | ||
| 5. Root system |
Compare the studied plants, list the similarities and differences.
Draw conclusions about the reasons for the similarities and differences.
Take a close look at the herbarium specimens of wheat. Fill the table
| Variety name | Characteristic features of the structure | Human use | Reason for the appearance of the symptom | Driving forces for the appearance of a trait |
Draw a conclusion: what could be the reasons and mechanisms of artificial selection in this case?
Laboratory work No. 3 “Study of bacterial cells”
Purpose: To study the structural features of a bacterial cell.
Equipment: Microscopes, ready-made micropreparations of bacterial cells.
Progress
1. Prepare the microscope for use.
2. Study of the features of the external structure of bacterial cells. Write captions for the pictures.
3. Study the features of the internal structure of a bacterial cell.
4. Draw the internal structure of a bacterial cell and make appropriate captions.
Conclusion: Describe the distinctive features of bacterial cells.
Laboratory work No. 4
“Preparing micropreparations of plant cells and examining them under a microscope. Comparison of plant, animal, fungal and bacterial cells"
Target: consolidate the ability to prepare microspecimens and compare the structure of cells of different kingdoms.
Equipment: microscopes, ready-made micropreparations of animal, fungal and bacterial cells, slides and cover glasses, onions, cups of water, iodine.
Progress.
Prepare a microslide of plant cells:
- Prepare a glass slide, wipe it with gauze...
Apply 1-2 drops of water to the glass.
Remove with a dissecting needle. peel from the inner surface of the onion scales.
Place a piece of peel in a drop of water and straighten it with the tip of a needle.
Cover the peel with a coverslip.
Examine the prepared preparation under a microscope.
Draw in your notebook and label: cell, cell wall, cytoplasm, nucleus.
Examine the finished microslide of an animal cell.
Examine the finished microslide of a bacterial cell.
Examine the finished microslide of a fungal cell.
Find similarities and differences in the structure of cells. Draw a picture and fill out the table.
| Structural features | Similarities | Features of difference |
||
| bacterial cell | ||||
| plant cell | ||||
| animal cell | ||||
| mushroom cell |
State your conclusion.
Laboratory work No. 5
“Solving genetic problems. Compilation of pedigrees"
Target: consolidate the ability to solve genetic problems of varying degrees of complexity and gain skills in drawing up pedigrees. 
Equipment: task cards.
Progress:
Solve the problem of monohybrid, dihybrid crossing, inheritance of sex-linked traits.
Use the notation to create your own pedigree.
Laboratory work No. 6
“Identification of variability in organisms. Construction of a variation curve"
Target: deepen knowledge about the reaction norm as the limit of adaptive reactions of organisms, develop knowledge about the statistical nature of the patterns of modification variability, develop the ability to experimentally obtain a variation series and construct a reaction norm curve.
Equipment: bean or pumpkin seeds (maple leaves) 100 pieces, pencil, ruler.
Progress:
Using a ruler, measure the length of the bean seeds and write the data in your notebook.
Count the number of seeds of the same length. Fill the table:
| Seed length | ||||||
| Number of seeds |
Determine which length is most common _________, and which is most rare ________.
Based on the data, construct a graph showing the frequency of occurrence of seeds of different lengths.
Number of seeds
Seed length
Draw conclusions about the patterns you discover.
Laboratory work No. 7 “Experiments on studying soil composition”
Target: Study the mechanical composition of the soil, determine soil moisture, study indicator plants.
Equipment: soil samples, porcelain cups, water
Progress:
Soil moisture determination
| Characteristics of soil lumps | Soil moisture |
| Drops of water ooze from the soil | Soggy soil |
| Water doesn't trickle out, but the soil is damp | Wet soil |
| The soil crumbles into lumps, but is moist | Fresh soil |
| The soil is crumbling | Dry soil |
Plants - soil indicators
Laboratory work No. 8
“Drawing up diagrams of the transfer of substances and energy (power circuits)”
Target: To get acquainted with complex food interactions between organisms, to form ideas about food chains and networks in natural biogeocenoses, about trophic and accompanying energy connections.
Equipment: instructional cards, descriptions of natural ecosystems.
Progress.
Using the list of types of oak forest biogeocenosis, distribute them according to trophic levels with the inclusion of organisms in the corresponding column of the table.
| Producers | 1st order consumers | Consumers of the 2nd order | Decomposers |
Oak, maple, rowan, squirrel, grass frog, decay bacteria, granivorous birds (finches, bullfinches), hazel, wolf, insectivorous birds (cuckoo, warblers), viper, earthworms, caterpillars, butterflies, bark beetles, hawks, ungulates (elk , wild boar, deer), anemone, molds, inorganic substances.
Make 2-3 power circuits.
What is the difference between a power circuit and a power network?
What practical significance is the definition of food networks in biogeocenoses, widely used by ecologists?
Explain why in China in the mid-20th century, after the destruction of sparrows, the harvest of grain crops decreased, because sparrows are granivorous birds.
Laboratory work No. 9
« Study and description of the ecosystem of your locality ty, identifying types of interaction between different species in this ecosystem
(using the example of an oak grove)"
Goal of the work:
1) study the structure of the oak forest biocenosis, consider indicators characterizing the biocenosis;
2) identify the diversity of interspecies relationships, determine their significance in nature and human life.
Equipment: table “Oak forest biocenosis”, herbarium plants and collections of animals of this biocenosis, instruction cards.
Progress.
1. Identify the tiers of the forest and describe the species composition of plants in each tier.
2. Note on what factors the layering of the forest depends.
3. Note the species composition of animals in each tier.
4. Give examples of the influence of plants on animals and animals on plants. Enter the data into the table.
| Types of relationships | Organisms that enter into relationships | Meaning |
| mycorrhiza | ||
| predation | ||
| competition |
5.Write examples of food chains in tiers.
Describe the lower tier of the forest (litter, soil, their inhabitants, mark the food chains).
Explain the significance of forests in nature and human life.
Conclusion. What is an oak forest?
Laboratory work No. 10
“Analysis and assessment of the consequences of human activities in ecosystems, their own actions on living organisms and ecosystems”
Goals:
to form an understanding of the interaction of environmental factors, the ability to assess the impact of human activities on species, ecosystems and make decisions on their protection.
to form ideas about the natural resource capabilities of the surrounding area, the ability to assess their condition and make decisions on their protection.
Equipment: map of environmental problems in Russia, information from periodicals about the impact of human activity on the biosphere and the environment.
Progress:
Task 1: The influence of the anthropogenic factor on the environment, flora and fauna (independent work in groups with textbook text, drawings, tables, printed texts).
1. Determine the forms of human influence on living nature.
2. Give examples of these influences.
3. Enter the data into the table.
Human influence on living nature.
Task 2. According to their consequences, the impact of human society on the environment can be positive and negative.
Write down in one column the positive and in the other negative consequences of the impact of human society on the environment - Conclude that there are more negative impacts, that people have not yet used all the possibilities to correct the caused violations.
Suggest ways to solve these problems.
Kemerovo region
Mariinsk
Municipal educational institution secondary school No. 7
Laboratory workshop in biology
Compiled by: Dmitrieva N.V.
Biology teacher
2002
Explanatory letter
School teachers constantly face the same question: how to raise a person who is useful to society, who understands his importance in the development of the country, who loves and desires the best not only for himself, but also for all the people around him.
It is not possible to educate such a person without developing in him a sustainable interest in his future profession, without developing in him the necessary skills to acquire a future profession in higher educational institutions. All these tasks can be accomplished only through the development of the ability to independently acquire the necessary knowledge during and after school hours.
The information received by students should not be imposed by the teacher, as many years of observations and research on this issue show, such information is not stored for a long time in the student’s memory. Students usually forget it very quickly. But a completely opposite picture emerges if the student acquires knowledge on his own. Due to certain circumstances, children, as a rule, study only the source of information that interests them. They mostly do not make mistakes in their choice. Taking this factor into account, many teachers set aside a little time in their lessons to give advice on issues of interest, on where to get a book with questions of interest, and also provide time during the lesson for independent study of certain topics, using additional sources of literature. Thus, it becomes clear that independent work for children is always more interesting than work under the guidance of a teacher. When a child works independently, he not only acquires some skills, but also develops his creative abilities in the research field.
In biology lessons, students can be asked to do laboratory work on their own. This will not only help children consolidate previously acquired knowledge, but will also help develop the skills and abilities that they will need in the future when studying at the faculties of the natural cycle of higher educational institutions.
To make it possible to organize work in the classroom in this way, we offer you a laboratory workshop in biology.
The purpose of creating a workshop is to develop students’ sustainable interest in the subject from the first day of studying it, as well as to develop the ability to independently perform any laboratory work in biology.
The set goal involves solving a number of problems:
to develop the ability of students to act independently according to the proposed instructions, the ability to perform biological drawings, and correctly format their work;
develop the ability to correctly determine the goal before performing work (since the entire work plan is before their eyes), and then draw appropriate conclusions; analyze their own activities;
develop the ability to independently use any laboratory equipment.
Develop cognitive interest in the work performed, the desire to independently conduct research on issues that interest them;
Develop the ability to plan your research work.
The variety of work offered allows them to be carried out both in class and outside of class time. This will not only increase interest in the subject, but will also contribute to the all-round development of the student and will help convince them of the truth of the knowledge they have learned and practical consequences.
The workshop presents work of varying levels of complexity. The level of complexity of work is determined by several indicators:
availability of special equipment for the work;
the difficulty of assessing what was seen or recorded in the experiment;
complexity of the mathematical apparatus (calculations, plotting, conclusions)
Using this workshop in the classroom, the teacher acts as a consultant on individual issues that arise during the work. Students like this form of work more than following the teacher’s clear instructions, because when conducting an experiment, a child cannot predict the result obtained in advance.
Chapter 1 Biological methods 8
Drawings in biology 8
Using a handheld magnifier 8
Using a microscope 8
Microscopic methods 9
preparing material for working with a microscope 9
Permanent microslides 9
Temporary microslides 10
Setting up protozoan cultures 10
Laboratory work No. 1 12
"Chemical composition of seed"
Laboratory work No. 2 12
“Study of the physical properties of proteins, fats, carbohydrates”
Laboratory work No. 3 12
"Structure of a plant cell"
Laboratory work No. 4 14
"Structure of an animal cell"
Laboratory work No. 5 14
"Tissues of plant organisms"
Laboratory work No. 6 14
"Structure of animal tissue"
Laboratory work No. 7 15
"Structure of the root system"
Laboratory work No. 8 16
“The structure of the kidneys. Their location on the escape"
Laboratory work No. 9 16
"Simple and compound leaves"
Laboratory work No. 10 16
"The structure of a flower"
Laboratory work No. 11 17
"Dry and juicy fruits"
Laboratory work No. 12 17
"Structure of seeds"
Laboratory work No. 13 18
"Structure of frog and human blood cells"
Laboratory work No. 14 18
"The effect of saliva on starch"
Laboratory work No. 15 19
"The effect of gastric juice on protein"
Laboratory work No. 16 19
"Movement of water and minerals"
Laboratory work No. 17 19
"Properties of Bones"
Laboratory work No. 18 20
"Movement of the ciliate slipper"
Laboratory work No. 19 20
"Earthworm Movement"
Laboratory work No. 20 20
"Cuttings of indoor plants"
Laboratory work No. 21 21
“Structure of the inflorescence” 22
Laboratory work No. 22
"Determination of seed germination"
Laboratory work No. 23 23
"Direct and indirect development"
Chapter 3 Diversity of living organisms 24
Laboratory work No. 1 24
"Growing white mold mucor"
Laboratory work No. 2 24
"The structure of the mold fungus - mucor"
Laboratory work No. 3 24
"Structure of yeast"
Laboratory work No. 4 25
“Structure of the fruiting body of a cap mushroom”
Laboratory work No. 5 25
"Structure of the multicellular alga Spirogyra"
Laboratory work No. 6 25
"Structure of green moss cuckoo flax"
Laboratory work No. 7 26
"The structure of sphagnum moss"
Laboratory work No. 8 26
"Absorption of water by sphagnum"
Laboratory work No. 9 27
"Structure of horsetail"
Laboratory work No. 10 27
"Structure of a spore-bearing fern"
Laboratory work No. 11 28
“Structure of needles and cones of coniferous plants”
Laboratory work No. 12 28
"The structure of male and female cones, pollen and pine seeds"
Laboratory work No. 13 29
“Identification of common characteristics of the cruciferous family by external structure”
Laboratory work No. 14 29
"The structure of the rosehip"
Laboratory work No. 15 30
“Identification of characteristics of the legume family by external structure”
Laboratory work No. 16 31
"Structure of wheat"
Laboratory work No. 17 31
"Structure of the ciliate slipper"
Laboratory work No. 18 33
"Freshwater polyp hydra"
Laboratory work No. 19 34
"External structure of an earthworm"
Laboratory work No. 20 36
"External structure of crayfish"
Laboratory work No. 21 38
"Structure and features of vital activity of gastropods"
Laboratory work No. 22 38
"External structure of insects"
Laboratory work No. 23 40
"skeletal structure of bony fish"
Laboratory work No. 24 41
"Structure of the skeleton of amphibians"
Laboratory work No. 25 41
"External structure and plumage of birds"
Laboratory work No. 26 42
"Structure of the skeleton of mammals"
Laboratory work No. 27 43
"Ecological groups of mammals"
Chapter 4 Man 44
Laboratory work No. 1 44
"Microscopic structure of human body tissues"
Laboratory work No. 2 44
“Determination of unconditioned reflexes of various parts of the brain”
Laboratory work No. 3 45
“Tests aimed at determining the volume of attention and the effectiveness of memorization”
Laboratory work No. 4 46
"Tests that determine the flexibility of the spine, poor posture, and the presence of flat feet"
Laboratory work No. 5 47
“Features of muscle function depending on working conditions”
Laboratory work No. 6 48
"Measuring Muscle Strength Using a Hand Dynamometer"
Laboratory work No. 7 49
"Movement coordination"
Laboratory work No. 8 50
Studying the structure of blood cells under a microscope"
Laboratory work No. 9 52
"Counting heart rate before and after exercise"
Laboratory work No. 10 53
“Carrying out instrumental analysis and functional tests, assessing blood pressure measurements”
Laboratory work No. 11 53
"Measuring blood pressure"
Laboratory work No. 12 54
“The influence of muscle activity on the speed of blood movement in the veins of the systemic circulation”
Laboratory work No. 13 55
"Minute and systolic blood volume"
Laboratory work No. 14 56
"Work of the Heart"
Laboratory work No. 15 56
"Carrying out functional breathing tests"
Laboratory work No. 16 57
“Hygienic assessment of indoor microclimate”
Laboratory work No. 17 58
"Diet planning"
Laboratory work No. 18 60
"Determination of breath holding time before and after exercise"
Laboratory work No. 19 60
“Determination of energy consumption based on the state of heart contractions”
Laboratory work No. 20 61
"Vital capacity of the lungs"
Laboratory work No. 21 61
"Study of the structure of skin, hair and nails"
Laboratory work No. 22 62
“Techniques for applying bandages to conditionally affected areas of the skin”
Chapter 5 Biology. General patterns of development. 62
Laboratory work No. 1 62
"Studying the issue of the emergence of microorganisms"
Laboratory work No. 2 62
"Cleavage of hydrogen peroxide by the enzyme catalase"
Laboratory work No. 3 63
"Movement of cytoplasm"
Laboratory work No. 4 64
"Observation of plasmolysis and deplasmolysis"
Laboratory work No. 5 65
“Structure of plant, animal, fungal cells under a microscope”
Laboratory work No. 6 65
"Conditions for the formation of starch in the leaves of green plants"
Laboratory work No. 8 67
“Solving genetic problems and drawing up a pedigree”
Laboratory work No. 9 70
"Morphological characteristics of plants of various species"
Laboratory work No. 10 71
"Variability of Organisms"
Laboratory work No. 11 72
"Adaptation of organisms to their environment"
Laboratory work No. 12 72
“Identification of aromorphoses in plants and ideological adaptations in insects”
Laboratory work No. 13 72
"Phenotypes of local plant varieties"
Laboratory work No. 14 73
“Variability, construction of variation series and variation curve”
Laboratory work No. 7 66
"Mitosis in the root of an onion"
Chapter 1. Biological methods
1.1 Drawings in biology
Target: 1) document the results of the work for future use.
2) Supplement visual observations and make it possible to see the object under study more accurately and completely.
30 promote memory by sketching what you see.
Rules: 1) you must use a notebook or drawing paper of appropriate thickness and quality. Pencil lines should be easily erased with it.
2) The pencil must be sharp, hardness HB, not colored.
3) The drawing must be:
Large enough - the more elements that make up the object under study. The larger the drawing should be.
Simple - include outlines of structure and other important details to show the location and relationship of individual elements.
Carefully executed - if an object has several similar parts, it is necessary to accurately draw out its small details;
Drawn with thin and distinct lines - each line must be thought through and then drawn without lifting it from the paper; do not hatch or paint;
The inscriptions should be as complete as possible, the lines coming from them should not intersect, leave space around the frame for the signature.
4) make two drawings if necessary:
Schematic drawing showing the main features.
Only details of small parts.
5) you should draw what you really see, not what you see. Whatever you think, and of course do not copy a drawing from a book.
6) each drawing must have a title indicating the magnification and projection of the sample. For example: cross section (CS), longitudinal section (Ll).
7. When sketching instruments, it is necessary to draw a vertical section and clearly show on it the tubes and valves through which gases can escape from the vessels.
1.2 Using a hand-held magnifying glass.
A hand magnifier is a biconvex lens inserted into a frame. A magnifying glass can be small (pocket size) or much larger, such as a magnifying glass used in anatomy. The hand-held magnifying glass should be held close to the eye and the object should be brought closer to the eye until a clear image appears.
1.3 Using a microscope.
Rules for using a microscope .
Store the microscope in a box or under a hood to protect it from dust.
remove it from the drawer with both hands and place it on the table gently to avoid jarring.
The lenses must be clean; to do this, wipe them with paper napkins.
The microscope must always be focused by moving the tube upward from the specimen, otherwise it may be damaged.
keep both eyes open and look with them in turn.
1.4 Microscopic methods.
1.4.1 Preparation of material for working with a microscope.
Biological objects can be studied both living and fixed.
In the latter case, the material for more detailed study can be divided into parts and processed with a number of different dyes. In order to identify and identify various structures. Temporary or permanent microslides can be prepared from the object under study.
1.4.2 Permanent microslides.
Fixation. This is the preservation of material in a state close to natural. The tissue must be killed quickly. This is best achieved when working with small pieces of living tissue. The substance used for this is called a fixative.
Dehydration. It is carried out when preparing the material for pouring or when enclosing it in an appropriate medium that does not mix with water. Water must also be removed because otherwise the drug will be destroyed by bacteria over time. In order to preserve the ultrastructure, dehydration must be carried out gradually, treating the material with a series of aqueous solutions of ethanol or propanone (acetone) with increasing concentrations and finishing the treatment with “absolute” (pure) ethanol or propanone.
Enlightenment. Some of the commonly used potting and sealing agents do not mix with alcohol. therefore, it must be gradually replaced with a medium (clarification agent) with which the casting medium is mixed, for example xylene. This also leads to the material becoming more transparent.
Filling. To obtain a thin section, it is necessary that the material be poured into a special medium. When preparing a microslide for light microscopy, objects are poured into paraffin, which is then allowed to cool.
Making sections. Sections can be made with a razor or microtome. To work on a conventional microscope, the section thickness should be 8–12 µm. The fabric should be secured between two pieces of elderberry. The razor is moistened with the liquid in which the fabric was stored; the cut is made through elderberry and fabric; The razor is held horizontally towards you and slowly moved in a sliding motion, directing it slightly at an angle.
Coloring. The structures on the preparation are transparent, so to obtain a contrast between them it is necessary to color them. Some dyes are given:
| Dye Color Material to be dyed Permanent dyes Aniline blue blue fungal hyphae and spores Boric carmine pink core: especially for large preparations Animal material. Eosin pink cytoplasm Feulgena red DNA dye (especially good at identifying chromosomes During cell division) Hematoxylin blue core; mainly for animal cuts Tissues combined with eosin are stained Cytoplasm; same for smears. Leishman dye red-pink blood cells Blue leukocyte nuclei Light green cytoplasm or cellulose Or durable green green Mitelen blue core blue Safranin red kernels, lignin and suberin in plants Mainly used for cutting Plant tissues. Temporary dyes Aniline sulfate yellow lignin Blue iodine solution - black starch Phloroglucenol+ Conc. HCl red lignin Schultz solution yellow lignin, cutin, suberin, protein. Blue starch Purple pulp |
Conclusion. The colored media are placed on a glass slide in special media. For example: in Canada balsam or euparol, which do not allow air to pass through and can retain the cut indefinitely. The enclosed section is covered with a coverslip.
Prepared for rapid preliminary research. To do this, the material is fixed, stained and enclosed in a medium. Fresh material cut
Can be done manually. Using a razor directly in a 70% alcohol solution, which serves as a fixative. A number of temporary dyes can be used for coloring and finishing. The section is placed on a clean glass slide and a few drops of dye are added. Then the preparation is covered with a thin coverslip. To prevent air and dust from entering.
1.4.4 Setting up protozoan cultures.
In natural conditions, protozoa can be found in small ponds, swamps, ditches, and forest puddles contaminated with plant debris. It is not always possible to find protozoa in nature immediately before classes, so living material is provided only by cultivation. At the beginning of the school year, it is necessary to create a culture of protozoa. Taking water samples from different parts of the reservoir. There are especially many protozoa in the bottom layers. Jars with samples are placed near the window. Direct sunlight should not hit them. With the exception of green flagellates, protozoa do not need good lighting. In the very first days, the contents are examined under a microscope and a label with the names of the detected protozoa is affixed to each jar. This will help you quickly find certain species when planting a crop. Cultures are planted no later than 2 - 3 weeks before the corresponding lesson. To successfully breed protozoa in the laboratory, several general rules must be followed:
Only glass containers should be used (beakers, any jars with a capacity of 0.5-1 liters).
Tap water must first be dechlorinated (stand for 7–10 days in a glass container, stir occasionally with a stick).
The volume of water should not exceed the diameter of the jar, otherwise it will be difficult for oxygen to penetrate into the bottom layers.
For the development of protozoa, the most favorable temperature is 18–23 C; a sharp change in temperature can lead to the death of protozoa.
Vessels with culture cannot be moved from place to place; to reduce water evaporation, they are covered with glass plates.
About a week before culturing the animals, a nutrient medium rich in bacteria should be prepared.
Chapter II Laboratory workshop for the course:
" Living organism"
Laboratory work No. 1
Topic: Chemical composition of seed
Target: to establish experimentally the presence of various organic substances in plant seeds.
Equipment: several grains of wheat, sunflower, bandage, beakers, wheat flour, test tube, holder, alcohol lamp.
Substances: water, iodine.
Progress:
Place a few seeds in a test tube and heat over low heat. What appeared on the walls of the test tube?
Add water to a small amount of wheat flour and make a ball of dough. Wrap a lump of dough in cheesecloth, place it in a glass of water and rinse it.
A viscous sticky mass remains in the gauze - this is gluten. Gluten is similar in composition to chicken egg white and is called vegetable protein.
Add 2 - 3 drops of iodine to a glass of cloudy water in which the dough was washed. What are you observing? What can be concluded?
Place a few sunflower seeds on the paper and crush them. What appeared on the paper?
Draw a conclusion: what organic substances are found in plant seeds. What other substance is included in the seeds?
Laboratory work No. 2
Topic: Study of the physical properties of proteins, fats, carbohydrates.
Target: compare the physical properties of proteins, fats, carbohydrates.
Equipment beakers, glass rods.
Substances: chicken protein, vegetable oil, starch, water.
Progress:
Consider the substances in beakers No. 1 protein, No. 2 starch, No. 3 vegetable oil. Enter your observations into the table.
Add a little water to each glass. What happened? Enter your observations into the table.
| Glass number | State of aggregation | color | smell | Reaction with water |
| №1 |
Reporting task
How do the substances you considered differ from each other?
Laboratory work No. 3
Topic Structure of a plant cell.
Target: identify the structural features of a plant cell.
Equipment: microscope, slide, cover glass, dissecting needle, filter paper, pipette.
Substances: iodine, water.
Plant material: onion skin, elodea leaf.
Progress:
Option 1
Take a glass slide and wipe it with a tissue to remove dust particles.
Place a drop of water in the center of the glass.
Take the scales of the onion and use a dissecting needle to remove the skin.
Place the skin of the onion scales in a drop of water on a glass slide and straighten it using a needle.
Cover the peel with a coverslip.
Examine the prepared preparation at low magnification and note which parts of the cell you see.
Stain the preparation with iodine solution. To do this, place a drop of iodine solution on a glass slide. Use filter paper on the other side to pull off excess solution.
Examine the colored preparation. What changes have taken place?
Examine the specimen at high magnification. Find a dark stripe on it - the membrane, under it there is a golden substance - the cytoplasm. The nucleus is clearly visible in the cytoplasm. Find the vacuole (it differs in color from the cytoplasm).
Sketch 2 - 3 cells of onion skin. Label: cytoplasm, nucleus, membrane, vacuole.
Option 2
Prepare a preparation of Elodea leaf cells. To do this, separate the leaf from the stem, place it in a drop of aoda on a glass slide and cover with a coverslip.
Examine the preparation under a microscope (lens x20, eyepiece x15). Find green plastids in the cells - chloroplasts.
Draw the structure of an Elodea leaf cell.
Reporting task:
Fill the table "Similarities and differences of plant cells"
Laboratory work No. 4
Topic: “Structure of an animal cell.
Target: Reveals the structural features of an animal cell.
Answer the question: what are the similarities and what are the differences in the structure of animal cells of different types of tissues.
Laboratory work No. 5
LABORATORY PRACTICUM
IN GENERAL BIOLOGY
FOR 10-11 CLASSES
Compiled
Shabalina Marina Germanovna, Deputy Director for Educational Management, Biology Teacher
Municipal educational institution "Sertolovskaya secondary school with in-depth study of individual subjects No. 2"
Name of laboratory work
1
Microscope structure and microscopic technology. Making a temporary microslide. Cell shape.
2
Catalytic activity of enzymes in living tissues.
3
The structure of a prokaryotic cell using the example of the bacterium Bacillus subtilis.
4
Air pollution by microorganisms.
5
General plan of the structure of plant and animal cells. Diversity of cells.
6
Intracellular movements. Movement of cytoplasm in Elodea cells.
7
Plasmolysis and deplasmolysis in onion skin cells.
8
Study of factors affecting the integrity of the cytoplasmic membrane.
9
Crystals of sodium oxalate as products of cellular metabolism.
10
Cell inclusions. Starch grains.
11
Chloroplasts, chromoplasts and leucoplasts are plastids of a plant cell.
12
Phases of mitosis
13
Studying the variability of plants and animals, constructing a variation series and curve
14
Studying the results of artificial selection
15
Study of type criteria
16
Study of the adaptability of organisms to their environment
17
Problems in molecular and general genetics
Laboratory work No. 1
Topic: “Microscope design and microscopic technology. Making a temporary microslide. Shape of cells."
Lesson objectives:
Study (remember) the structure of a school microscope and master microscopy techniques.
Make a temporary preparation of a moss leaf, examine the cells, and compare them.
Get to know the variety of cells.
Learn how to properly format laboratory work.
Using the methodological development, study the structure of a light microscope and the rules for working with it. Draw a microscope (using the rules for designing laboratory work - see below) in a notebook for practical classes, indicate its details in the drawing.
Task No. 1
Study the structure of a light microscope and master the technique of working with it
Consider the main parts of the microscope: optical and mechanical.
Optical part includes lenses installed in the sockets of the microscope revolving device; an eyepiece located in a tube, a lighting device.
Lens – complex lens system. The most commonly used lenses are x8 and x40.
Eyepiece – magnifies the image transmitted by the lens. The most commonly used eyepieces are x7, x10, x15, x20.
Associated with the optical part lighting device, including: a) mirror(may be concave on one side - used in artificial lighting; flat on the other side - used in natural lighting); b) iris diaphragm, built into the condenser - to change the degree of illumination of the drug; V) capacitor, with the help of which a beam of light is focused on the drug. Using a mirror, a beam of light is sent to the condenser and through it to the preparation.
TO mechanical part microscope includes: base, stage, tube, revolver, tripod, screws.
Increase, obtained in a microscope is determined by multiplying the magnification of the objective by the magnification of the eyepiece.
Let's move on to mastering microscopy techniques.
Place the microscope with the tripod handle facing you against your left shoulder, approximately 2-3 cm from the edge of the table. Wipe the lens, eyepiece and mirror with a cloth.
Place the x8 lens in working position. To do this, rotate the microscope turret so that the desired lens is perpendicular to the stage. The normal position of the lens is achieved when a slight click of the revolver is heard.
Remember that studying any object begins with low magnification!
Use a mirror to direct the light into the opening of the stage. While looking through the eyepiece with your left eye, rotate the mirror in different directions until the field of view is brightly and evenly illuminated. If there is not enough light, increase the aperture opening.
Place the microspecimen on the stage with the cover glass facing up so that the object is in the center of the hole in the stage.
Looking at the lens from the side, using the adjustment screws, raise the stage so that the distance from the cover glass to the lens is no more than 5-6 mm.
Look through the eyepiece and at the same time slowly lower the stage using the adjustment screws until a clear image of the object appears in the field of view. When moving the specimen on the stage, examine its general appearance. Then, in the center of the field of view, place the area of the specimen that needs to be examined at high magnification.
Turn the turret and install the x20 lens into working position. The sharpness should be adjusted using the screw.
When sketching a specimen, look into the eyepiece with your left eye and into the notebook with your right.
When finishing work with the microscope, use a revolver to replace the high-magnification lens with a low-magnification lens and remove the microspecimen from the table. Place the microscope in the designated place.
Task No. 2
Prepare a preparation of a mnium leaf, examine and sketch the cells.
A) to prepare a microslide, you need to take a glass slide and apply a drop of water to its middle with a glass rod. Place one leaf of moss in a drop.
B) take a cover glass and, holding it at an angle, trying not to stain it with your fingers, touch the drop with its edge and lower it evenly. There should be no air bubbles left on the moss sheet. If there are any, you need to add water with a glass rod to the side of the cover glass. If the glass floats, excess water must be removed with a piece of filter paper.
C) begin to examine the object, using the rules for working with a microscope.
D) draw, looking through a microscope, various cells, color the chloroplasts in green. Make the necessary notations in the figure (using the instructions for preparing laboratory work).
D) draw conclusions from laboratory work.
Please carefully read the rules for completing laboratory work.
Rules for completing laboratory work
A necessary element of microscopic study of an object is sketching it in a notebook. The purpose of sketching is to better understand and consolidate in memory the structure of an object and individual structures.
To make sketches, you must have pencils - simple and colored (but not felt-tip pens!).
When sketching, the following rules must be observed:
before starting the sketch, write down the name of the topic or laboratory work at the top of the page, and before each drawing - the name of the object;
the drawing should be large, the details should be clearly visible; there should be no more than 3-4 drawings on one page;
the drawing must correctly display the shape and size of the whole object, as well as the ratio of the sizes of its individual parts;
You should not draw contours of the microscope field of view around the drawings;
In each drawing, designations of its individual parts must be made; to do this, place arrows on individual parts of the object, and write a certain number against each arrow; it is desirable that all arrows be parallel; then, on the side of the drawing or under it, numbers are written in a column vertically, and against the numbers - the name of the part of the object;
The inscriptions for the drawing are made with a simple pencil
Laboratory work No. 2
Topic: “Catalytic activity of enzymes in living tissues”
Goal of the work:
Develop knowledge about the role of enzymes in cells, consolidate the ability to work with a microscope, conduct experiments and explain the results of the work.
Catalysis is the process of changing the rate of a chemical reaction under the influence of various substances - catalysts participating in this process and remaining chemically unchanged at the end of the reaction. If the addition of a catalyst accelerates a chemical process, then this phenomenon is called positive catalysis, and slowing down the reaction is called negative. More often we encounter positive catalysis. Depending on their chemical nature, catalysts are divided into inorganic and organic. The latter also include biological catalysts – enzymes.
The well-known hydrogen peroxide decomposes slowly without catalysts. In the presence of an inorganic catalyst (iron salts), this reaction proceeds somewhat faster. During the cell's metabolism, hydrogen peroxide can also be formed in it, the accumulation of which in the cell can cause its poisoning. But almost all cells contain the enzyme catalase, which destroys hydrogen peroxide at an incredible speed: one molecule of catalase breaks down in 1 minute. more than 5 million molecules of hydrogen peroxide. Other examples include the following. The human stomach produces the enzyme pepsin, which breaks down proteins. One gram of pepsin per hour can hydrolyze 50 kg of egg white, and 1.6 g of amylase, synthesized in the pancreas and salivary glands, can break down 175 kg of starch in an hour.
Option #1
Equipment:
Fresh 3% hydrogen peroxide solution, test tubes, tweezers, plant tissue (pieces of raw and boiled potatoes), and animal tissue (pieces of raw and cooked meat or fish), sand, mortar and pestle.
prepare 5 test tubes and place a little sand in the first test tube, a piece of raw potato in the second, a piece of boiled potato in the third, a piece of raw meat in the fourth, a piece of boiled meat in the fifth. Drop a little hydrogen peroxide into each test tube. Observe what happens in each of their test tubes.
Grind a piece of raw potato with a small amount of sand in a mortar (to sufficiently destroy the cell). Transfer the crushed potatoes along with the sand into a test tube and drop a little hydrogen peroxide into it. Compare the activity of crushed and whole plant tissue.
Make a table showing the activity of each tissue under different treatments.
Tube number
Object of study
Observed result
No. 1, etc.
Explain your results by answering for control questions:
In which test tubes did the enzyme activity manifest itself? Why?
How does enzyme activity manifest itself in living and dead tissues? Explain the observed phenomenon.
How does grinding tissue affect enzyme activity?
Does enzyme activity differ in living tissues of plants and animals?
Do you think all living organisms contain the enzyme catalase? Justify your answer.
Option 2.
Equipment:
Microscopes, slide and cover glasses, glasses with water, glass rods, hydrogen peroxide, elodea leaf.
Sequence of work:
Prepare a preparation of an elodea leaf, examine it under a microscope and sketch several cells of the leaf.
Drop hydrogen peroxide onto the microslide and observe the condition of the cells again.
Explain the observed phenomenon. Answer the questions: what gas is released from leaf cells? Why is it released? Write the equation for the corresponding reaction.
Place a drop of hydrogen peroxide on a glass slide, examine it under a microscope, and describe the observed picture. Compare the state of hydrogen peroxide in the elodea leaf and on the glass.
Write a lab report. Formulate conclusions based on your research.
Laboratory work No. 3
Topic: “Structure of a prokaryotic cell using the example of Bacillus subtilis bacterium”
Goal of the work:
Strengthen the ability to prepare microscopic specimens and examine them under a microscope.
Find structural features of cells, make observations and explain the results obtained.
Method for obtaining a culture of Bacillus subtilis bacteria:
A handful of dry hay is crushed with scissors and placed in a beaker or other container. Pour water in a volume 2 times larger than the hay mass and boil for 30 minutes. Then the infusion is filtered through cotton wool, poured into a flask, tightly capped and placed in a dark cabinet at a temperature of up to 30 degrees C. After 3-5 days, a whitish film of hay sticks forms on the surface of the hay infusion.
Bacillus subtilis are quite large (1.5-3 microns) and are clearly visible at high magnification.
Equipment:
Microscopes, culture of the bacterium Bacillus subtilis, slide and cover glass, dissecting needle, black ink.
Sequence of work:
Apply a drop of ink to a glass slide. Using a dissecting needle, remove the film from the hay infusion and place it in a drop of ink. Mix thoroughly with a needle and cover with a coverslip on top.
Examine the prepared microslide first under low, then under high magnification. Light oblong cells are visible. These are bacteria - hay bacilli.
Draw in your notebook the chains of hay sticks and also one enlarged individual.
If you put the infusion with hay sticks in a cold place or start to dry it, you can observe sporulation. Each individual Bacillus subtilis (cell) produces only one spore; in this case, the contents of the cell are compacted and covered with a new, very dense shell, the original shell of the bacterium is destroyed. At high magnification, you can see oval bodies - spores - inside the cells of Bacillus subtilis.
Using the same method, prepare a micropreparation of Bacillus subtilis from the infusion, which was kept under unfavorable conditions.
Draw the spores of the bacteria Bacillus subtilis.
Formulate a conclusion by answering control questions:
1. What is the basis for the division of all living organisms into two groups - prokaryotes and eukaryotes?
2. What organisms are prokaryotes?
3. What are the structural features of a bacterial cell?
4. How do bacteria reproduce?
5. What is the essence of the process of sporulation in bacteria?
Laboratory work No. 4
Topic: Air pollution by microorganisms.
Goal of the work:
Get acquainted with the general provisions and methods of working with microorganisms;
do an analysis of the air microflora by the number of colonies on the nutritional plate.
Theoretical justification of the work:
Microorganisms are classified as biological pollutants of the atmosphere. Causing spoilage of food, destroying books, furniture, buildings, being sources of human diseases, they have a negative impact on people's lives. By examining air samples using microbiological methods, it is possible to determine the degree of its contamination with bacteria and fungi and take measures to disinfect it.
Practical part of the work
Equipment:
Petri dishes (or sterile glass jars with metal lids) filled with nutrient medium.
Sequence of work:
describe the room, note the time of the experiment.
Take a sterile container and open the lid in the area to be examined for 15 minutes (place it, without turning it over, next to the jar).
Bring the sample to class and place it in a warm place (26 degrees C)
Reporting task
Fill out the table.
Compare the studied places in terms of microbiological contamination and identify the most unfavorable ones.
Taking into account the characteristics of living organisms, try to understand what determines the growth and distribution of microorganisms in each study location.
What will you do to reduce microbiological air pollution?
Summary table of microbiological examination (options of examination sites may vary):
Study location
Number of colonies
No. 1 School yard
No. 2 Corridor
No. 3 Dining room
№4 Dressing room
No.5 Office
Laboratory work No. 5
Topic: “General plan of the structure of plant and animal cells. Cell diversity."
Goal of the work:
Study the structural features of plant and animal cells. Make sure that, despite some differences and structural features, cells of both types are arranged according to a single plan.
Sequence of work:
Task No. 1 Study the structure of onion skin cells
Theoretical part of laboratory work (study carefully)
Living cells of the skin - epidermis - juicy scales of onions are a good object for studying the nucleus and cytoplasm under a microscope, as well as their derivatives: the cell wall and vacuole.
On the outside, the nucleus is covered with a nuclear membrane, and its cavity is occupied by nuclear juice. It houses the chromosome-nucleolus complex. However, in a nondividing cell, chromosomes are not visible because they are despiralized. Nucleoli (most often there are two of them), on the contrary, are clearly visible in a non-dividing cell.
The cell wall under a microscope is visible as a line, which is interrupted by lighter areas - pores. They are non-thickened areas of the cell wall. Plasmadesmata pass through them (they are not visible), connecting cells to each other.
Practical part of laboratory work (perform sequentially)
Remove the thin film, the epidermis, from the inner surface of the fleshy scales of the bulb.
Place a piece of epidermis on a glass slide in a drop of water.
Cover the object with a cover glass.
Examine epidermal cells under different magnifications of a microscope.
Carry out a staining reaction of epidermal cells with a solution of iodine in potassium iodide. Place a drop of the solution on a glass rod to the edge of the cover glass, and suck off the water from the opposite side of the glass with filter paper. The solution that has penetrated under the cover glass will color the cytoplasm yellow and the nucleus light brown. This reaction confirms the presence of protein substances in the nucleus and cytoplasm.
Draw several cells of the epidermis, indicating in the drawing: cytoplasm, nucleus, vacuoles, cell membrane, pores. Try to find the stomata.
Task No. 2 Study the structure of squamous epithelial cells in the human oral cavity
Sequence of work:
To prepare the drug, use a sterile spatula to apply light pressure across the palate or gums. In this case, at the tip of the spatula, in a drop of saliva, there will be desquamated cells of the epithelium lining the oral cavity.
Apply a drop of saliva to the slide and cover it with a coverslip.
Examine the specimen at high magnification with the condenser diaphragm covered.
The specimen shows individual large flat cells of irregular shape. Most of the cells are dead, so the nucleus is clearly visible in them.
Draw several cells, indicate the nucleus and cytoplasm.
Final control part of laboratory work (complete in writing):
What are the main parts of any cell?
What do the structures of plant and animal cells have in common?
How are these cells different?
How can we explain that, being arranged according to a single plan, cells are very diverse in shape and size?
Laboratory work No. 6
Topic: “Intracellular movements. Movement of the cytoplasm in the cells of the Elodea leaf."
Goal of the work:
1. Strengthen the ability to prepare microscopic specimens and examine them under a microscope.
Observe the movement of cytoplasm in a cell.
Strengthen the ability to explain the results obtained.
Sequence of work:
Theoretical part of the laboratory work (carefully study and briefly take notes)
Intracellular movements - movements of the cytoplasm and organelles (chloroplasts, mitochondria, nucleus, chromosomes, etc.) inside the cell are characteristic of all organisms. They are observed in living cells of plants, animals and microorganisms. Most often, in cells one can see internal currents of the cytoplasm and organelles and granules passively moving in it. It is difficult to observe active movements of organelles, although most of them are capable of independent movements.
The biological significance of intracellular movements is great: they ensure the movement of substances within the cell, the regulation of the permeability of cell membranes, the intensity of photosynthesis processes (in green plant cells), the divergence of chromosomes during nuclear division, etc.
It is obvious that studying the causes and mechanisms of intracellular movements is a necessary condition for understanding the laws of cell activity. Therefore, the problem of intracellular movements is one of the important problems of modern cytology.
Types of intracellular movements:
The movements of the cytoplasm are characterized by significant diversity. The main types of motion are: oscillatory, circulating, rotational and gushing.
Oscillatory movement is considered the least ordered, has an unstable and random character. With this type of movement, some areas of the cytoplasm are at rest, others slide towards the periphery, and others - towards the center of the cell (see Fig. 1, A).
Circulating movement characteristic of plant cells that have protoplasmic strands crossing the central vacuole (for example, large cells of the hairs of the integumentary tissues of nettle and tradescantia, algae cells, etc.). In these cells, the cytoplasm moves around the vacuole (along the cell membrane) and in strands crossing the vacuole. The direction of the circulation movement is not constant, it periodically changes to the opposite. (see Fig. 1, B).
Rotational movement - the most ordered type of movement, characteristic of plant cells that have fairly rigid membranes and a large central vacuole. It is often found in the leaf cells of aquatic plants (Elodea, Valisneria, Nitella, Chara), in the cells of root hairs, pollen tubes, and in cambium cells. With this type of movement, the movement of the cytoplasm occurs along the periphery of the cell and has a more or less constant character (see Fig. 1, B).
Gushing the movement is characterized by the fact that in the center of the cell the cytoplasm moves in one direction, and in the parietal layer in the opposite direction (cytoplasmic currents resemble the movement of jets in a fountain). This type of movement is considered intermediate between circulatory and rotational. Fountaining motion can be observed in root hair cells and pollen tubes of many plants. (see Fig. 1, D).
Influence of external factors on intracellular movements
External factors - heat, light, chemicals - can have a significant impact on the movement of the cytoplasm and cellular organelles. For example, the movement of the cytoplasm in Elodea cells completely stops at temperatures below 10 and above 42 degrees C. The most intense movement of the cytoplasm is observed at a temperature of 37 degrees C. The presence of various chemicals in the environment can have a significant stimulating effect on the movement of the cytoplasm of some aquatic plants.
Causes of intracellular movements
Cytoplasmic proteins that have the ability to reversibly contract are responsible for intracellular movements. They are organized into quite complex structures that can be combined into two main systems - the microfilament system and the microtubule system.
Microfilaments are long filament-like structures 5-7 nm thick, consisting mainly of the protein actin. The microfilament protein actin has a globular structure and is capable of polymerizing to form long fibrillar structures (see Fig. 2).
Actin filaments can be scattered in the cytoplasm and can form groups or bundles. When carrying out movement, actin filaments interact with thicker filaments consisting of the myosin protein (see Fig. 3).
In non-muscle cells, microfilaments are responsible for changes in cell shape, movement of the cytoplasm and cellular organelles. Cell division and other processes.
Microtubules have the form of cylindrical formations with a diameter of 15–25 nm, with a wall thickness of about 5–8 nm and a channel diameter of less than 10 nm. The length of the tubes is several micrometers. The main protein from which microtubules are built is tubulin. Tubulin shows striking similarities to actin, from which microfilaments are built. Another protein, dynein, which is part of additional structures - special bridges, with the help of which microtubules slide relative to each other, is also of great importance in the movements of microtubules.
Microtubules are either scattered throughout the cytoplasm or collected in organized structures. With their help, intracellular movements of the cytoplasm and organelles are carried out, they participate in maintaining the shape of the cell, in the intracellular transport of substances, the secretion of end products, and in the movement of chromosomes during cell division. The motility of cilia and flagella in microorganisms is also associated with the functioning of microtubules (see Fig. 4)
Mechanism of intracellular movements
Microfilaments can move in two ways: by sliding actin and myosin filaments relative to each other or by polymerization and depolymerization of microfilaments (in this case, the movement is not caused by sliding, but by an increase in the length of actin microfilaments by polymerizing them from one end. This increase in the length of the filament leads to movement of that part of the cell that is in contact with the zone of growth of microfilaments. The reverse process occurs when microfilaments are destroyed.).
Microtubules, like microfilaments, generate movement in two ways: by actively sliding microtubules relative to each other or by changing their length.
Additional structures, dynein bridges, connecting microtubules play an important role in the sliding movement of microtubules.
Movement can also be caused by lengthening and shortening of microtubules. These changes are due to their partial polymerization and depolymerization.
Practical part of laboratory work
Equipment: a sprig of elodea placed in a glass of water (three drops of alcohol were first added to the glass), microscope, slide and cover glass, tweezers, dissecting needles, pipette, napkin.
The passive movement of chloroplasts is easy to observe in the cells of the aquatic plant Elodea, the entire leaf of which can be examined under a microscope without preparing sections. Chloroplasts move most quickly in elongated cells of the leaf vein and near the edge of the leaf, where the speed of cytoplasmic movement is greatest. The movement of the cytoplasm is stimulated by a small amount of ethanol (3 drops) added to a glass of elodea.
Sequence of work:
Place one Elodea leaf in a drop of water on a glass slide. Cover with a cover glass.
Examine the microscopic specimen at low magnification and observe the movement of the cytoplasm. To do this, move the preparation so that the elongated central cells are clearly visible. Focusing on one chloroplast, follow its movement in the flow of cytoplasm.
Draw one cell of an elodea leaf. Arrows show the direction of cytoplasmic movement and determine its type.
Draw a final conclusion on the laboratory work.
Laboratory work No. 7
Topic: “Plasmolysis and deplasmolysis in onion skin cells”
Target: develop the ability to conduct experiments on obtaining plasmolysis, consolidate the ability to work with a microscope, conduct observations and explain the results obtained.
Theoretical part of the laboratory work:
When cells are exposed to hypertonic solutions, plasmolysis is observed. Plasmolysis is the detachment of the cytoplasm from the cell walls or its shrinkage. This happens because, as a result of diffusion, water moves from an area with a lower salt concentration to an area with a higher salt concentration. Plasmolysis in a cell can be caused by any solution of neutral salt, sugar, or glycerol. After washing the drug with water, the cell restores its original structure. This process is called deplasmolysis. These processes are based on the diffusion of water through semi-permeable membranes.
Practical part of laboratory work:
Equipment: microscopes, slides and coverslips, glass rods or pipettes, glasses of water, filter paper, hypertonic sodium chloride solution, onion scales.
Sequence of work:
Prepare a preparation of onion skin and examine the cells under a microscope. Note the location of the cytoplasm relative to the cell membrane.
Remove water from the microslide by placing filter paper on the edge of the coverslip. Apply a few drops of hypertonic sodium chloride solution to the preparation. Examine the preparation under a microscope and observe changes in the position of the cytoplasm.
Sketch the cell. Mark in the picture the changes that have occurred to the cell.
Using filter paper, remove the hypertonic sodium chloride solution. Rinse the preparation with water (up to three times), by applying water several times and removing it with filter paper.
Apply a few drops of water to the skin of the onion scales. Observe changes in the cell.
Draw one cell. Mark in the picture the changes that have occurred to the cell.
Draw a general conclusion by answering the control questions:
Where did the water move (into or out of the cells) when the tissue was placed in a hypertonic saline solution?
How can one explain this direction of water movement?
Where did the water move when the fabric was placed in water? What explains this?
What do you think could happen in the cells if they were left in a salt solution for a long time?
What is the process of diffusion of water through a selectively permeable membrane called? What is the direction of diffusion?
What is meant by the term osmotic pressure?
Define the concept of turgor, physiological solution?
Laboratory work No. 8
Topic: “Study of factors affecting the integrity of the cytoplasmic membrane of a plant cell”
Theoretical part of the laboratory work:
We present to your attention a small study on the properties of the cytoplasmic membrane of a plant cell. Red cabbage is used in this study. The vacuoles of its cells contain the water-soluble pigment anthocyanin, which gives its leaves their characteristic color. When the cell wall, cytoplasmic and vacuolar membranes of the cell are destroyed, anthocyanin comes out and colors the solution in the test tube. In the course of the work, it is proposed to find out the effect of various chemicals on the cell membrane.
For the purity of the experiment, you need to use the same test tubes, the same pieces of cabbage (the same thickness and area), add the same amount of all chemicals. During the experiment (part No. 2), it is proposed to use only pieces that have been washed from pigment. To completely remove anthocyanin from destroyed cells, you need to cut a sufficient number of cabbage pieces in advance and soak them in tap water for 3 hours, changing the water several times.
Identical pieces of cabbage, dried with paper, are placed in dry test tubes. The choice of substances is not accidental: ethanol is a polar compound, hydrochloric acid and sodium hydroxide are electrolytes. They interact mainly with the polar (hydrophilic) components of the membrane (proteins, glycoproteins, polar heads of phospholipid molecules) and cause denaturation of proteins and their partial extraction from membranes. All this leads to disruption of the integrity of cell membranes and the release of pigment into solution. Hydrochloric acid and alkali react chemically with anthocyanin, giving the solution a red and yellow color, respectively. For this reason, anthocyanin can be used as a natural indicator for the detection of hydroxyl anions and hydrogen cations in aqueous solution.
Acetone is a nonpolar solvent that interacts mainly with nonpolar (hydrophobic) components of the membrane (tails of phospholipid molecules, intramembrane groups of proteins). In addition, acetone, like ethanol, causes denaturation of proteins.
Table salt is a polar compound, but under experimental conditions it does not destroy cell membranes, so the solution in the test tube remains colorless.
When demonstrating a demonstration experiment, the teacher or one of the students is asked to find out the effect of temperature on the integrity of the cytoplasmic membrane. One test tube is placed in a bath at a temperature not higher than 40 degrees C, the other at a temperature not lower than 60 degrees C, the third test tube is boiled for several minutes. At temperatures above 40 degrees C, proteins denature, the integrity of the membranes is disrupted, and anthocyanin enters the water, giving it a blue color. When pieces of red cabbage are boiled, the anthocyanin released into the water undergoes thermal decomposition and turns pale green.
In all experiments, it is necessary to note not only the color of the solution, but also the color of the cabbage pieces. The pieces may become discolored completely or only along the edges, depending on the number of destroyed cells. In experiments with hydrochloric acid and sodium hydroxide, the pieces turn the same color as the solution. This may indicate that hydrogen and hydroxyl ions penetrate into the cells and interact with anthocyanin there.
Practical part of laboratory work:
Equipment: red cabbage leaves; tweezers; 7 test tubes or penicillin vials; laboratory rack for test tubes; graduated cylinder or 5 ml plastic syringes; filter paper; a sheet of white paper as a background for test tubes; water; ethanol(96%); acetone; hydrochloric acid solutions (1M); sodium hydroxide(1M); sodium chloride(10%).
Sequence of work:
Part 1
Cut 3 square pieces from red cabbage leaves. Make sure the pieces are the same.
Place the cabbage pieces in a test tube and add 5 ml of water. Number this test tube No. 1.
Place the test tube in a rack.
Note the color changes in the contents of the tube. It is convenient to determine the color of a solution against a sheet of white paper.
Part 2
Take another test tube and repeat steps 2 and 3, using cabbage pieces previously soaked in water. Number this test tube number 2.
Number 5 test tubes: No. 3, No. 4, No. 5, No. 6, No. 7.
Place the washed cabbage pieces on filter paper and blot them thoroughly. Place the dried pieces into test tubes and add 5 ml of the following liquids instead of water:
In test tube No. 3 – ethanol (96%)
In test tube No. 4 - acetone
In test tube No. 5 - hydrochloric acid (1M)
In test tube No. 6 - sodium hydroxide (1 M)
In test tube No. 7 - sodium chloride solution (10%)
Note the color of the contents of all test tubes (use a piece of white paper as a background)
Part 3
Watch carefully the demonstration experiments shown by the teacher or one of the students.
Note the color changes in all test tubes.
Present the results in the form of a table:
Tube number
Content
Test tubes and temperature
Coloring the liquid contents of a test tube
Coloring cabbage pieces
No. 1, etc.
Explain the results of your work and record your conclusion in a laboratory report, answering the test questions:
In what part of a living cabbage cell is the anthocyanin pigment located? (Please accompany your answer with a drawing and captions)
Where was anthocyanin found during the experiment?
For what purpose were cabbage pieces soaked in water for some time used in the experiment?
What does the cytoplasmic membrane consist of? (Please accompany your answer with a picture)
Which of the substances that make up the membrane are hydrophilic and which are hydrophobic? Which substances added to the test tubes are polar and which are nonpolar?
Why did the color of the solution not change in the experiment with sodium chloride solution?
Why can liquid detergents be harmful to the skin?
How can anthocyanin be used in a chemistry laboratory?
Laboratory work No. 9
Topic: “Sodium oxalate crystals as products of cellular metabolism”
Goal of the work:
Familiarize yourself with the crystals of sodium oxalate formed in some plant cells.
Theoretical part of the work:
Crystals of calcium oxalate are found in large quantities in the filmy dry scales of onion bulbs. They are prismatic in shape, single or fused in twos or threes. The crystals are formed from oxalic acid, which does not remain in a free state in the cell sap, but is neutralized by calcium.
In addition to calcium oxalate, crystals of calcium carbonate (in dahlia tubers, agave leaves), calcium sulfate (in tamarisk leaves, chicken millet, and in the tissues of some algae) are also common in plant cells.
As products of secondary metabolism in the cell, crystals often accumulate in those plant organs that are periodically shed - leaves, bark, bud scales. Epidermal hairs. The shape of crystals is very diverse and often specific to certain plants.
Equipment:
Filmy dry onion scales, slide and cover glass, glass of water, glass rod.
Sequence of work:
Prepare a microslide of dry onion scales.
First, at low, then at high magnification, examine single and group crystals of calcium oxalate.
Sketch one or two cells with crystals. Make the necessary signatures.
Draw a general conclusion about laboratory work.
Laboratory work No. 10
Topic: “Cell inclusions. Starch grains."
Goal of the work: Study the shape and structure of starch grains of potato tubers.
Theoretical part of the laboratory work:
Plant reserve nutrients - fats, proteins and carbohydrates - are needed by the plant and are used by it at different times.
Fats in the form of oil droplets are deposited in cell organelles - spherosomes. The seeds and fruits of such plants as sunflower, castor bean, hazel, olive, and mustard are especially rich in fats.
Storage proteins are deposited in cell sap. When the vacuoles dry out, aleurone grains are formed. The seeds of legumes and cereals are very rich in proteins.
Carbohydrates are the most common storage substances in plants. Water-soluble carbohydrates - glucose, fructose, sucrose, inulin - accumulate in cell sap. They are rich in the fruits of apple trees, pears, grapes, root crops of carrots and beets, dahlia tubers and earthen pears. A water-insoluble carbohydrate, starch, is deposited in the form of starch grains in leucoplasts. The storage organs of plants are rich in it: seeds (cereals and legumes), tubers (potatoes), bulbs (tulip, hyacinth), rhizomes (iris, lily of the valley).
Starch grains have different shapes and sizes. Depending on the number of starch formation centers and the nature of complexity, simple and complex starch grains are distinguished.
The shape, size and structure of starch grains are specific to each plant. These features are widely used for microscopic analysis of flour composition.
Practical part of laboratory work:
Equipment:
Potato tuber, dissecting needle, glass of water, glass rod or pipette, slide and cover glass, microscope.
Sequence of work:
Take a potato tuber, cut it with a scalpel and scrape the cut site with a dissecting needle.
Dip a needle into a drop of water onto a glass slide to wash off the scraped pulp. Carefully, without pressing, cover the drop with a coverslip.
Examine the specimen at high magnification. Larger and smaller starch grains are visible in the field of view. By reducing the light flow onto the specimen using an iris diaphragm and a condenser, the layering of the grains can be seen. It depends on the different water content of the grain layers. If the starch is dried, the layering will disappear. Most starch grains are simple. However, try to find complex grains in your field of vision.
Draw the types of potato starch grains, showing their layering in the drawing.
On the same preparation, without removing it from the table, carry out a coloring reaction of starch with a solution of iodine in potassium iodide. When the reagent penetrates under the coverslip, a blue coloration of the grains will occur. If there is an excess of the reagent, the starch turns black. Draw a picture, write down the name of the reagent and the result of the reaction.
What reserve substances are in the plant and where are they deposited? Where are starch grains deposited?
How do complex starch grains differ from simple ones?
What determines the layering of grains on a micropreparation?
What are inclusions called?
Laboratory work No. 11
Topic: “Chloroplasts, chromoplasts and leucoplasts - plastids of a plant cell. »
Goal of the work:
1. Study the shape and location of chloroplasts in the cell.
To study the structural features of chromoplasts in the pulp cells of ripe fruits.
Study the shape and location of leukoplasts in a cell.
Theoretical part of the laboratory work:
Plastids (chloroplasts, leucoplasts and chromoplasts) are obligatory organelles of plant cells. They are clearly visible in a light microscope. Plastids are located in the cytoplasm. Cytoplasm is a colorless granular liquid with the biological properties of living matter. Metabolism occurs in it, it grows and develops, and has irritability.
Chloroplasts are lenticular green bodies. This color is due to the presence of chlorophyll. The process of photosynthesis occurs in chloroplasts.
Chromoplasts are orange-red or yellow plastids. Their color depends on carotenoid pigments. The shape of chloroplasts is different. Chromoplasts give bright color to ripe fruits (rowan, rosehip, tomato), root vegetables (carrots), flower petals (nasturtium, buttercup), etc. bright colors attract pollinating insects, birds, and animals. This helps the fruit spread.
Leucoplasts are colorless, round plastids. They accumulate starch in the form of starch grains. Most leucoplasts are formed in the storage organs of plants - tubers, rhizomes, fruits, seeds.
Practical part of the work:
Equipment:
Microscope, slides and cover glasses, glass of water, glass rod or pipette, Elodea leaf, rowan or tomato fruit, Tradescantia virginiana, dissecting needles, tweezers, glycerin, sugar solution.
Sequence of work:
Part 1
prepare a preparation for studying chloroplasts. To do this, place one leaf of Elodea canada in a drop of water on a glass slide. Carefully cover with a coverslip.
Place the specimen on the microscope stage so that the edge of the leaf is visible. Examine it at low and then at high magnification.
Along the edge of the leaf, the cells are arranged in a single layer, so to study them there is no need to make a thin section. Chloroplasts look like round green bodies. Those seen from the side are shaped like a biconvex lens.
Draw one cell of an Elodea leaf, show the chloroplasts, color them.
Part 2
Make a preparation for studying chromoplasts - a preparation of the pulp of the rowan fruit or the pulp of the tomato fruit. To do this, pipet a drop of glycerol solution onto a glass slide. It is a clearing liquid, so the image quality of plastids is significantly improved.
Use a dissecting needle to open the fruit and take a little pulp on the tip of the needle. Place it in a drop of glycerin, after rubbing it lightly. Cover with a cover glass.
At low magnification, find the place where the cells are least crowded. Set the microscope to high magnification. In bright light, adjust the clarity of the outline of the cells using the screw. Examine chromoplasts, noting the characteristic features of their shape and color. The nucleus and cytoplasm in such cells may not be visible.
Sketch the cell of the pulp. Color the chromoplasts.
Part 3
Prepare a preparation for studying leucoplasts. Apply a drop of a weak sugar solution to a glass slide, which is used instead of pure water to prevent the leucoplasts from swelling. Take a leaf of a houseplant, Tradescantia virginiana, and use tweezers or a dissecting needle to remove a small piece of epidermis from the underside of the leaf. Place it in a drop of solution and cover with a coverslip.
At low magnification, find lavender cells. The cell sap in them is colored with anthocyanin.
Turn the microscope to high magnification and examine one cell. The core in it is located in the center or pressed against one of the walls. In the cytoplasm surrounding the nucleus, leukoplasts are visible in the form of small bodies that strongly refract light.
Draw one cell and make notations. Color the cell sap.
Part 4
Draw a general conclusion by answering the control questions:
What are the characteristic differences between a plant cell and an animal cell?
What types of plastids are distinguished in a plant cell?
What role does each type of plastid play?
Can plastids transform into each other? Prove with examples.
Why is it possible to increase the number of plastids by dividing them in two?
Laboratory work No. 12
Topic: Phases of Mitosis
Goal of the work:
Study the phases of mitosis in meristematic cells of the root growth cone.
Theoretical part of the laboratory work:
The growth of plant organs in length and thickness occurs due to an increase in the number of cells as a result of mitotic division. Cells in which one division follows another are called meristematic. They have thin cellulose walls, thick cytoplasm and large nuclei. In the interphase nucleus, the chromosomes are despiralized and therefore indistinguishable under a light microscope. During division, they spiral, shorten and thicken. Then they can be counted, their shape and size determined.
The continuous process of mitotic division has four phases: prophase, metaphase, anaphase and telophase. All of them are clearly visible under a light microscope.
Practical part of the work:
Method for preparing the pressed preparation:
Onions, pea and rye seeds, as well as indoor plants - chlorophytum, coleus, tradescantia - are used as objects of research.
To obtain roots, tradescantia and coleus are sprouted with stem petioles, chlorophytum - with babies in cups of water. Pea and rye seeds are soaked for 24 hours. then, after swelling, they are transferred to damp sand for germination. The sand is pre-washed and calcined. Onion bulbs are germinated in tap water in jars (volume 250 ml) or Petri dishes (onion seeds) for a week or more.
As the roots grow, they are cut off and placed in an acetic-alcohol fixative (3 parts glacial acetic acid and 1 part ethyl alcohol) for 3-4 hours (another option is 1 day). The optimal root length for all of these plants is 1-2 cm. The volume of the fixing liquid should exceed the volume of the material by approximately 50 times. After fixation, the roots are washed 2-3 times in a 70% alcohol solution (another option is for 45 minutes in 5N hydrochloric acid). After this, the material is painted. Acetolacmoid dye (dye preparation: 2.2 g of lakmoid and 100 ml of glacial acetic acid are heated for several minutes - do not bring to a boil and left to cool; the solution is filtered through a paper filter; diluted 2 times with distilled water, obtaining approximately 1% solution lakmoid in 45% acetic acid) or acetoorcein (dye preparation: 1 g of orcein is dissolved in 55 ml of hot acetic acid. After cooling, add 45 ml of distilled water. Before use, the dye is filtered. The roots must be dyed in small portions of the dye (5-6 ml per 10-12 roots.)).
To prepare a crushed preparation from the root extracted from the dye, cut off the tip 4-5 mm long. This is done on a glass slide with a dissecting needle. Then cover with a coverslip and lightly tap the cover glass with a match to crush the object. The result is a monolayer of cells.
Sequence of work:
Examine the prepared microspecimen of a plant root tip.
Among meristematic cells, find cells with interphase nuclei. The nucleoli and membrane are clearly visible in them. These are the majority of cells, since interphase lasts many times longer than the mitotic phases.
Carefully examining the dividing nuclei, find the phases of mitosis.
Draw the phases of mitosis in order and label them. Label the cell wall, cytoplasm, nucleus, nucleoli, chromosomes, spindle.
Draw a general conclusion on laboratory work
Complete an additional task: using the given microphotographs of mitosis in plant and animal cells, distribute the stages of mitosis in order.
LABORATORY WORK No. 13
“Study of plant and animal variability, construction of variation series and curve”
Goal of the work:
Get acquainted with the statistical patterns of variability, with the methodology for constructing a variation series and variation curve, learn to experimentally identify the patterns of nature.
THEORETICAL PART OF THE WORK:
Before you begin the lab, answer the following questions:
What is the significance of modification variability?
What is the relationship between modification variability and the genotype of any organism?
Express your guess about the causes of modification variability.
What is a reaction norm, is it inherited?
Decipher the following concepts: variant, variation series, variation curve
In the list of signs, indicate those that are characterized by a narrow reaction rate:
A) plant height b) animal weight c) human pupil color d) hare ear size e) polar bear fur color f) fish brain size g) giraffe neck length
PRACTICAL PART OF THE WORK:
Equipment:
On each table there are sets of biological objects: bean seeds, broad beans, ears of wheat, potato tubers, leaves of cherry laurel, apple tree, acacia, etc.
Progress:
1A. Construction of a variation series.
1) From the objects offered to you, select a sign by which you can
conduct research.
Place objects in a row as the selected feature becomes stronger (build a variation row)
Determine the number of samples similar to the characteristic under consideration.
Write down the numerical expression of the variation series in your notebook.
1B. The following variation series for options are given:
Option 1.
Variability in the number of marginal (reed) flowers in a chrysanthemum inflorescence
Number
marginal flowers in
one inflorescence
The number of such inflorescences
Option 2.
Variability in the number of bone rays in the caudal fin of the flounder
Number of rays in the fin
Number of such individuals
Construction of a variation curve.
Construct the coordinate axes: along the abscissa axis
The degree of expression of the trait, along the ordinate - the frequency of occurrence of the trait
Construct a variation curve, which is a graphical expression of the variability of a trait
Explain the revealed pattern of frequency of occurrence of individual variants in the variation series.
3. Calculation of the average value of the severity of a trait using the formula (p. 232, task No. 3.)
4. Draw a conclusion reflecting on what factors the severity of modification variability depends and how this is reflected in the variation curve.
LABORATORY WORK No. 14
"STUDYING THE RESULTS OF ARTIFICIAL SELECTION"
Goal of the work:
To get acquainted with the variety of animal breeds (plant varieties), make a comparison with the ancestral form, identify directions and prospects for selection and genetic work.
Equipment:
Flashcards
PRACTICAL PART OF THE WORK:
Fill out the table:
Varieties or breeds
Wild ancestor, center of domestication
General signs
Various signs
Genetic basis for the presence of these characteristics
Reasons for the diversity of varieties or breeds
The fate of those with unfavorable changes
The fate of those with favorable changes
The significance of the results of artificial selection for practice
THEORETICAL PART:
We list several interrelated biological phenomena and their results: 1) uncertain variability 2) certain variability 3) heredity 4) artificial selection 5) divergence (divergence of characters) 6) formation of several new breeds of domestic animals (cultivated plant varieties) from one ancestral species 7) suitability of breeds and varieties to human interests and needs 8) diversity of breeds and varieties 9) human needs to increase the productivity of domestic animals (cultivated plants)
Determine and depict schematically, with the participation of which biological phenomena listed above, various breeds of pigeons arose (p. 366 of the textbook) and what results this led to. The relationship of phenomena according to the theory of Charles Darwin must be shown on the diagram with arrows, directing them from cause to effect; the phenomena themselves - indicated by numbers; highlight the factor that is the main driving force behind the formation of a new breed or variety in the diagram with a double circle or a different color.
LABORATORY WORK No. 15
GAMETHOGENESIS AND INITIAL STAGES OF ONTOGENESIS
PURPOSE: To become familiar with the preparations of the stages of formation of germ cells and the initial stages of embryo development.
EQUIPMENT: Prepared preparations of testis and ovary, fixed sperm and eggs, microscopes.
PROGRESS:
1. Examine and sketch germ cells at different stages of spermatogenesis from the finished preparation. Determine the stage of spermatogenesis.
To do this, study the following information:
The preparation shows seminiferous tubules cut in different directions. Select one of the tubules for a more detailed study. Most of the section through the tubule is occupied by sac-like cysts adjacent to the tubule membrane. The walls of the cyst are formed by follicular cells. Inside the cysts are germ cells. In each cyst, cell development occurs synchronously.
In different cysts, germ cells can be observed at different stages of spermatogenesis. Cysts with germ cells during the growth period are easy to detect: spermacites of the 1st order are the largest, spermacites of the 2nd order are noticeably smaller. The largest volume is found in cysts with spermatids, which are loosely located in the cavity of the cysts. In the later stages of spermatid development, they become oval and a tail filament appears. At the final stage of spermatogenesis, the head becomes rod-shaped and the tail filament lengthens.
2. On the finished microslide, study the structure of spermatozoa, sketch it, and make the appropriate designations in the figure.
ANSWER REVIEW QUESTIONS:
What do spermatogenesis and oogenesis have in common and how do they differ from each other?
What is the set of chromosomes in human gametes?
Give examples of vegetative propagation in plants.
What is a spore?
LABORATORY WORK No. 15
"STUDYING THE CRITERIA OF A SPECIES"
GOAL OF THE WORK:
Prove that in order to establish that an individual belongs to a given species, it is necessary to know several criteria that characterize the individual comprehensively.
EQUIPMENT:
Illustrative material (lake and pond frogs), additional biological literature, geographical atlas.
Theoretical part of the work:
A species is a collection of individuals that are similar in terms of species criteria to such an extent that they can naturally interbreed and produce fertile offspring. Fertile offspring are those that can reproduce themselves. An example of infertile offspring is a mule (a hybrid of a donkey and a horse), it is infertile.
Criterion from the Greek "kriterion" - a means of judgment. A criterion is a sign by which the type of organism is determined. The criteria by which one can judge whether these individuals belong to the same species are as follows:
Morphological – internal and external structure.
Physiological-biochemical – how organs and cells work.
Behavioral - behavior, especially at the time of reproduction.
Ecological – a set of environmental factors necessary for the life of a species (temperature, humidity, food, competitors, etc.)
Geographical – area (area of distribution), i.e. the territory in which the species lives.
Genetic-reproductive - the same number and structure of chromosomes, which allows organisms to produce fertile offspring.
Type criteria are relative, i.e. A species cannot be judged by one criterion. For example, there are twin species (in the malaria mosquito, in rats, etc.). They do not differ morphologically from each other, but have a different number of chromosomes and therefore do not produce offspring. (That is, the morphological criterion does not work [is relative], but the genetic-reproductive criterion does).
Practical part of the work:
PROGRESS:
Consider the proposed animal and determine its type according to the following criteria.
Morphological.
1………..The body length is 6-13 cm, weight - up to 200 g. The body is elongated, the muzzle is oval, slightly pointed. On top, the body is colored brown-green in different shades with dark spots. A light stripe of varying degrees of severity runs along the head and spine of most individuals (up to 90%). The lower part of the body is colored off-white or slightly yellowish, in most cases with numerous dark, sometimes black spots. The eyes are bright golden in color.light olive color, pear-shaped. If the shins are pressed to the hips and located perpendicular to the longitudinal axis of the body, then the ankle joints overlap each other. The inner molasses tubercle is low. Males with smoky gray resonators at the corners of the mouth.
2.The length of the body……of the frog rarely exceeds 8 cm. The color of the dorsal side is usually bright green, gray-green, olive or brown, with more or less dark spots, a narrow light longitudinal stripe often runs along the middle of the back, the ventral side is plain white or yellowish. Some individuals have no dorsal pattern and small spots on the throat or front of the belly.well developed. The sides of the head often have stripes that extend from the tip of the snout through the nostrils, eyes, and sometimes the eardrums. On the lower part of the foot there is a high and laterally compressed calcaneal tubercle, and there are swimming membranes. In males, dark brown nuptial calluses are developed on the first two or three inner fingers of the forelimbs, and on the sides of the head in the corners of the mouth there is a pair of white external sound resonators. During the breeding season, the body of males may have a yellowish tint.
Geographical
1………..the frog is common in and , and , in . IN distributed up to 60° N, found in, on , in . In the east - to the lake.
2………the frog is common in the central from western in the west to in the east (crosses to the left bankin its middle course). Northern border passes through, southern and further through the northwest(and), and . In the south the border partially coincides with And and is limited to the north, northern foothills and , north , central-southern regions.
Ecological 1………frog lives in permanent, fairly deep (more than 20 cm) reservoirs. Most often these are rivers, ponds, ditches, lakes, but it can often be found and along river banks. Active almost around the clock. In cases of danger, the frog usually hides in the water. It hunts mainly on land, along the banks of reservoirs; here it can most often be found during the warmest time of the day - from 12 to 17 o'clock.
Frogs usually winter in the same reservoirs where they live during the warm season, but sometimes they migrate to deeper places where there are springs. They leave for the winter when the water temperature drops to 8-10 °C. In non-freezing reservoirs with warm water, frogs are active almost all winter.
2………lives in low-flow or stagnant shallow water bodies And , found after breeding in moist forests and far from water. IN And lives only in bodies of water, mainly in rivers and . The acidity of such reservoirs varies within= 5.8-7.4. It rises to a height of up to 1550 m in the mountains..
Enter the research results into the table
Types of frogs
Morphological criterion
Geographical criterion
Ecological criterion
Ozernaya:
Male
female
Prudovaya:
Male
female
Draw a conclusion by answering the following questions:
By what characteristics did you classify the proposed organisms as different species?
Prove that species identification is impossible based on only one of the species criteria.
Justify why there are species that are similar, it would seem, in all characteristics, but do not interbreed?
Are there difficulties in identifying the type of plant found in nature?
Are morphological criteria characteristic of all types of organisms? Justify your answer.
LABORATORY WORK No. 16
“STUDYING THE ADAPTATION OF ORGANISMS TO THE ENVIRONMENT”
GOAL OF THE WORK:
Establish the mechanism of adaptation of organisms to their environment and make sure that any adaptation is relative and is the result of the action of natural selection.
EQUIPMENT:
Handouts in the form of individual illustrative cards.
Theoretical part of the work
Adaptation is the correspondence of the characteristics of an organism (internal and external structure, physiological processes, behavior) to the environment, allowing it to survive and produce offspring. For example, aquatic animals have a streamlined body shape; the green color of the back makes the frog invisible against the background of plants; The tiered arrangement of plants in the biogeocenosis makes it possible to effectively use solar energy for photosynthesis. Adaptation helps organisms survive in the conditions in which it was formed under the influence of the driving forces of evolution. But even in these conditions it is relative. A white partridge reveals itself as a shadow on a sunny day. The white hare, invisible in the snow, is clearly visible against the background of dark trunks.
Examples of adaptations:
examples of morphological adaptation:
1. Protective coloration - coloration in organisms living in open spaces. For example: polar bear, tiger, zebra, snakes.
2. Camouflage - body shape and color blend with surrounding objects. For example: pipefish, seahorse, caterpillars of some butterflies, stick insects.
3. Mimicry - imitation of a less protected species by a more protected one. For example, a hoverfly is a wasp; some snakes. It is necessary, however, that the number of the imitator species be significantly less than the number of the model. Otherwise, mimicry is not beneficial: the predator does not develop a strong conditioned reflex to the shape or color that should be avoided.
4. Warning coloring - bright coloring and protection from eating (sting, poison, etc.). for example, ladybird beetle, toaded toad, tropical tree frogs.
5. Adaptation to extreme conditions. For example, camel thorn has a long root that goes underground for tens of meters and modified leaves - spines.
6. Coevolution - adaptations of some species to others. For example, insect-pollinated flowers. The process of evolution and adaptation of each species does not occur in a biological vacuum, independent of other forms. On the contrary, some species often have a significant influence on the evolution of others. As a result, various interdependencies between species arise. Some plants cannot survive in areas where there are no insects to pollinate them.
ethological or behavioral adaptations:
1. Freezing (opossums, some beetles, amphibians, birds) and a threatening posture (bearded lizard, long-eared lizard) - protection from being eaten by carnivores.
2. Stockpiling food (nutrition, jay, chipmunk, squirrel, pika) - experiencing food shortage
Practical part of the work:
PROGRESS:
1. Carefully examine the organisms offered to you on the illustrative cards and:
Identify the most obvious devices and classify them.
Note the environmental factors that these devices correspond to.
Explain the biological significance of these devices.
Enter the research data into the table:
Adaptations
Environmental factors to which the adaptation corresponds
Biological significance
2. Draw a conclusion on the laboratory work by answering the following questions:
1) What advantages did organisms receive due to the acquisition of the characteristic traits of fitness that you identified?
2) Provide evidence of relative adaptability to environmental conditions (using the example of representatives of the card issued to you)
3) Explain how the adaptive characteristics you identified could have arisen, if we assume that the ancestors of these organisms did not have them.
TASKS IN MOLECULAR AND GENERAL GENETICS
MOLECULAR GENETICS
Task No. 1
A fragment of a DNA molecule consists of nucleotides arranged in the following sequence: TAAAATGGCAACC. Determine the composition and sequence of amino acids in the polypeptide chain encoded in this part of the gene.
Task No. 2
A fragment of a protein molecule contains amino acids: aspartic acid - alanine - methionine - valine. Define:
A) what is the structure of the section of the DNA molecule encoding this sequence of amino acids
B) the number (in%) of different types of nucleotides in this part of the gene (in two chains)
C) the length of this gene region.
Task No. 3
The molecular weight of protein X is 50 thousand. daltons (50kDa). Determine the length of the corresponding gene.
Note. The average molecular weight of one amino acid can be taken equal to 100 Da, and one nucleotide - 345 Da.
Task No. 4
A fragment of the myoglobin protein molecule contains amino acids arranged in the following order: Valine - alanine - glutamic acid tyrosine - serine - glutamine. What is the structure of the section of the DNA molecule that encodes this sequence of amino acids?
Problem #5
The nucleotide sequence of the gene region is given: A-A-T-T-T-G-G-C-C-A-C-A-C-A-A. What amino acid sequence is encoded in this region?
Problem #6
The DNA strand is given: C-T-A-T-A-G-T-A-A-C-C-A-A. Determine: a) the primary structure of the protein encoded in this chain; 6) the number (in%) of different types of nucleotides in this gene; d) the primary structure of the protein synthesized after the loss of the ninth nucleotide in this DNA chain.
Problem No. 7
One of the chains of a DNA molecule has the following nucleotide sequence: AGTACCGATACCTCGATTTACG... What is the nucleotide sequence of the second chain of the same molecule?
Problem No. 8
Indicate the order of nucleotides in the DNA chain formed by self-copying the chain: CACCTGTACAATCGCTGAT...
Problem No. 9
A section of one of the chains of deoxyribonucleic acid (DNA) molecules was examined in the laboratory. It turned out that it consists of 20 monomers, which are arranged in the following sequence: GTGTAACGACCGATACGTA. What can be said about the structure of the corresponding section of the second Chain of the same DNA molecule?
Task No. 10.
The larger of the two insulin protein chains (called Chain B) begins with the following amino acids: phenylalanine-valine-asparagine-glutamic acid-histidine-leucine. Write the sequence of nucleotides at the beginning of the section of the DNA molecule that stores information about this protein (using the heredity code).
Problem No. 11
The chain of amino acids of the ribonuclease protein has the following beginning: lysine-glutamine-threonine-Alanine-alanine-alanine-lysine... What sequence of nucleotides does the gene corresponding to this protein begin with?
Problem No. 12
What sequence of DNA nucleotides encodes a protein section if it has the following structure: proline-valine-arginine-proline-leucine-Valine-arginine?
Problem No. 13
The smaller chain of monomers in the insulin molecule (the so-called A chain) ends with the following amino acids: leucine-tyrosine-asparagine-tyrosine-cysteine-asparagine. What sequence of DNA nucleotides ends with the corresponding gene?
Problem No. 14
What sequence of amino acids is encoded by this sequence of DNA nucleotides: CCTAGTGTGAACCAG... and what will the sequence of amino acids be if Thymine is inserted between the sixth and seventh nucleotides?
Problem No. 15
Name the successive monomers of a section of a protein molecule that is synthesized on the basis of information “recorded” in the DNA molecule in the following order of nucleotides: TCTTTCCAAAAAAGATA... How will the removal of the fifth nucleotide from the DNA molecule affect the structure of the protein?
GENERAL GENETICS
MONOHYBRID CROSSING
Task No. 1
Determine the genotypes and phenotypes of the offspring of brown-eyed heterozygous parents.
Problem No. 2
Find the ratio of smooth and wrinkled seeds in peas in the first generation obtained by pollinating plants with wrinkled seeds with pollen of homozygous plants with smooth seeds.
Problem No. 3
Red-fruited gooseberry plants, when crossed with each other, produce offspring with red berries, and white-fruited gooseberry plants produce white ones. As a result of crossing both varieties with each other, pink fruits are obtained.
1.What kind of offspring will be obtained when heterozygous gooseberry plants with pink fruits are crossed with each other?
2. What kind of offspring will be produced if a red-fruited gooseberry is pollinated with pollen from a hybrid gooseberry with pink fruits?
Problem No. 4
In snapdragon, plants with wide leaves, when crossed with each other, always produce offspring with narrow leaves, and plants with narrow leaves only produce offspring with narrow leaves. As a result of crossing a broad-leaved individual with a narrow-leaved one, a plant with leaves of intermediate width appears. What will be the offspring of a cross between two individuals with leaves of intermediate width? What happens if you cross a narrow-leaved plant with a plant that has leaves of intermediate width?
Problem No. 5
In tomatoes, the gene for normal growth dominates the gene for dwarfism. How tall will the offspring be from crossing homozygous tall plants with dwarf plants? What kind of offspring... should be expected from crossing the hybrids just mentioned? What is the result of backcrossing representatives... with a dwarf parental form?
Problem No. 6
Standard minks have brown fur, while Aleutian minks have bluish-gray fur. Both are homozygous, with the brown color being dominant. What offspring F will be obtained from crossing the two named breeds? What will happen as a result of crossing such hybrids with each other? What will be the result of backcrossing an Aleutian father with his hybrid daughter?
Problem No. 7
Immunity to smut in oats dominates over susceptibility to this disease. What offspring F will be obtained from crossing homozygous immune individuals with plants affected by smut? What happens from crossing such hybrids with each other? What will be the result of backcrossing F plants with a parental form lacking immunity?
Problem No. 8
The gene for fertility (in this case, the ability of pollen to fertilize) of the corn panicle dominates the gene for sterility (in this case, one of the types of sterility, which is called “nuclear”; sterility due to other reasons is inherited differently). What kind of pollen will be produced by corn obtained from crossing homozygous plants with fertile panicles and plants with sterile panicles? What happens from crossing such hybrids with each other? What will be the result of backcrossing plants with a parental form that has panicles with sterile pollen?
Problem No. 9
A blue-eyed young man married a brown-eyed girl whose father had blue eyes. From this marriage a brown-eyed child was born. What is the child's genotype?
Task No. 10.
In humans, the gene for polydactyly (multi-fingered) dominates the normal structure of the hand. The wife has a normal hand, the husband is heterozygous for the polydactyly gene. Determine the probability of having a multi-fingered child in this family.
Task No. 11.
In minks, brown fur color dominates over blue fur. A brown female was crossed with a blue male. Among the offspring, two puppies are brown and one is blue. Is the female purebred?
Problem No. 12
A blond woman whose parents had black hair marries a black-haired man whose mother has blond hair and whose father has black hair. The only child in this family is fair-haired. What was the probability of a child appearing in a family with exactly this hair color, if the gene for black hair dominates the gene for blond hair?
Problem No. 13
A couple suffering from farsightedness gave birth to a child with normal vision. What is the probability of a child with farsightedness in this family, if it is known that the farsightedness gene dominates the gene for normal vision?
Problem No. 14
An albino child was born into a family of healthy spouses. What was the probability that such a child would appear in this family if it was known that the paternal grandmother and maternal grandfather of this child were also albinos? The occurrence of albinism is controlled by a recessive gene, and the development of normal pigmentation is controlled by a dominant gene.
Problem No. 16
Young parents are surprised that they, who have the same (2) blood group, have a child who is different from them and has 1 blood group. What was the probability of such a child being born in this family?
Problem No. 17
A young woman came to a medical genetic consultation with a question: what will the ears of her future children look like if she has flattened ears, and her husband’s ears are somewhat protruding? The husband's mother has protruding ears, and his father has flattened ears. It is known that the gene that controls the degree of protruding ears is dominant. And gen. Responsible for the degree of ear flatness is recessive.
INCOMPLETE DOMINANCE
Problem No. 18
In humans, the gene for fine hair is a gene of incomplete dominance in relation to the gene for straight hair. From the marriage of a woman with straight hair and a man with wavy hair, a child is born with straight hair, like the mother's. Could this family have a child with wavy hair? With fine hair? It is known that heterozygotes have wavy hair.
Problem No. 19.
The offspring of horses of white and bay colors always have a golden-yellow color. Two golden yellow horses give birth to foals: a white and a bay. Calculate what was the probability of the appearance of such foals if it is known that the white color is determined by the dominant gene of incomplete dominance, and the bay color is determined by the recessive gene. Will there be golden yellow foals among the offspring of these horses? What is the probability of such foals appearing?
Problem No. 20.
If in wheat the gene that determines the short ear length does not completely dominate the gene responsible for the appearance of a long ear, then what length can appear when crossing two plants with ears of medium length?
DIHYBRID CROSSING
Task No. 1
It is known that the six-fingered gene (one of the types of polydactyly) and the gene that controls the presence of freckles are dominant genes located in different pairs of autosomes. A woman with a normal number of fingers on her hands (with five fingers) and with cutely scattered freckles on her face marries a man who also has five fingers on each hand, but not from birth, but after an operation in childhood to remove the excess ( sixth) finger on each hand. There were no freckles on the man’s face from birth, and there are none at present. This family has an only child: five-fingered, like the mother, and without freckles, like the father. Calculate the probability of these parents giving birth to just such a child.
Problem No. 2
It is known that cataracts and red hair in humans are controlled by dominant genes localized in different pairs of autosomes. A red-haired woman who does not suffer from cataracts is married to a fair-haired man who has recently had cataract surgery. Determine what kind of children these spouses might have, keeping in mind that the man's mother has the same phenotype as his wife (i.e., she is red-haired and does not have this eye disease).
Problem No. 3
What characteristics will hybrid apricots obtained as a result of pollination of dihomozygous red-fruited plants of normal growth with pollen of yellow-fruited dwarf plants have? What will be the result of further crossing of such hybrids?
Problem No. 4
In humans, the free earlobe (A) dominates over the non-free one, and the chin with a triangular fossa (B) dominates over the smooth chin. A man has a loose earlobe and a chin with a triangular dimple, and a woman has a loose earlobe and a smooth chin. They had a son with a loose earlobe and a smooth chin.
A) How many types of gametes are produced in a man?
B) How many different phenotypes can children in this family have?
C) How many different genotypes can the children in this family have?
D) What is the probability of having a baby with a loose earlobe and a smooth chin?
D) What is the probability of having a child with a triangular dimple in the chin?
C) What is the probability that recessive homozygotes will be born in this family twice in a row?
g) What is the probability that recessive homozygotes will be born four times in a row in this family?
Problem No. 5
In Datura, the red color of the flowers (A) dominates over the white, and the spiny seed pods (B) dominate over the smooth ones. Heterozygous plants were crossed and 64 offspring were obtained.
A) How many types of gametes does each parent plant have?
B) How many different genotypes are formed from such a cross?
Q) How many plants with red flowers will there be?
d) How many plants with white flowers and spiny seed pods will there be?
e) How many different genotypes will there be among plants with red flowers and smooth seed pods?
Problem No. 6
In tomatoes, round fruits (A) dominate over pear-shaped ones, and the red color of the fruits (B) dominates over yellow ones. A plant with round red fruits was crossed with a plant with pear-shaped yellow fruits. All plants produced round red fruits in their offspring.
A) What numbers indicate the genotypes of the parents below?
B) What numbers indicate the genotypes of the hybrids below?
C) How many types of gametes does a hybrid plant produce?
D] What kind of phenotypic split should there be in the offspring if a plant with pear-shaped yellow fruits is crossed with a plant that is diheterozygous (for these characteristics)?
E) What kind of phenotypic split should there be in the offspring if a plant with pear-shaped yellow fruits is crossed with any partial heterozygote?
Problem No. 7
The coloration of a rabbit's fur (as opposed to albinism) is determined by a dominant gene. The color of the color is controlled by another gene located on another chromosome. Moreover, gray color dominates over black (in albino rabbits, color genes do not manifest themselves). What characteristics will the hybrid forms obtained from crossing gray rabbits with albinos carrying the black color gene have? The original animals are assumed to be homozygous for both genes mentioned here. What proportion of F2 rabbits will be black?
Problem No. 8
It is known that normal growth in oats dominates over gigantism, and early ripening dominates over late ripening. All original plants are homozygous and the genes for both traits are located on different chromosomes. What characteristics will hybrids of early-ripening oats of normal growth with late-ripening giant oats have? What will be the result of further crossing such hybrids with each other?
Problem No. 9
Feathered legs in chickens (as opposed to naked) are determined by a dominant gene. The pisiform comb dominates the simple comb. What characteristics will the hybrid forms obtained from crossing chickens with pea-shaped combs, which have feathered legs, have with bare-legged chickens, which have simple combs? The original animals are assumed to be homozygous for both genes mentioned here. What part of F2 will end up with a pisiform crest and bare legs?
Problem No. 10
It is known that cataracts and red hair in humans are controlled by dominant genes localized in different pairs of autosomes. A red-haired woman who does not suffer from cataracts is married to a fair-haired man who has recently had cataract surgery. Determine which children these spouses can have, if we keep in mind that the man’s mother has the same phenotype as his wife /i.e. she is red-haired and does not have cataracts).
Task No. 11.
From the marriage of a red-haired woman with cheerful freckles on her face and a black-haired man who does not have freckles, a child was born whose genotype can be written as digomorecessive. Determine the genotypes of the child’s parents, the phenotype of the offspring itself, and the likelihood of such a child appearing in this family.
Task No. 12.
In humans, brown eye color dominates over blue, and the ability to better use the right hand dominates over left-handedness, and the genes for both traits are located on different chromosomes. A brown-eyed right-hander marries a blue-eyed left-hander. What kind of offspring in relation to these characteristics should be expected in such a family? Consider two cases: when a young man is homozygous for both characteristics and when he is heterozygous for them.
Task No. 13.
Hereditary blindness in humans can have many different causes. In this problem and No. 14, we will have in mind only two types of blindness, the cause of each of which is determined by its recessive gene. How likely is it that a child will be born blind if his father and mother both suffer from the same type of hereditary blindness? And if different? Connect the answer you received with the need to take special care to ensure that blind people marrying each other are not even distantly related.
Problem No. 14.
Estimate the probability of a child being born blind if his parents are sighted and both grandmothers suffer from the same type of hereditary blindness (see problem No. 13). What if grandmothers’ blindness is caused by different genes? In both cases, it is assumed that the genotypes of the grandfathers are not burdened with blindness genes.
Problem No. 15
A homozygous yellow Drosophila with very narrow wings without bristles is crossed with a normal Drosophila. What kind of hybrids will be and what kind of offspring will result from crossing these hybrids with each other? It is known that the recessive gene for yellow color and the dominant gene for narrow wings is located on the second chromosome, and the recessive gene for the absence of bristles is on the third.
INHERITANCE OF SEX-LINKED CHARACTERS
Task No. 1
A woman with hypoplasia (thinning) of tooth enamel marries a man who has the same defect. From this marriage a boy is born who does not suffer from this disease. What was the probability of a healthy boy appearing in this family, unlike his parents, who did not suffer from enamel hypoplasia? What is the probability of having a healthy girl in this family?
It is known that the gene responsible for the development of enamel hypoplasia is a dominant gene localized on the X chromosome; the gene that controls the absence of the disease in question is a recessive gene on the X chromosome.
Task No. 2
The marriage of a man who does not have rickets, resistant to treatment with vitamin D, and a woman suffering from this disease, produces a healthy girl. Can she be absolutely sure that all subsequent children born in this family will be as healthy as this first-born girl?
It is known that the gene responsible for the development of this disease is a dominant gene of complete dominance, localized on the X chromosome.
Task No. 3
It is known that the hemophilia gene (non-clotting blood) is a recessive gene localized on the X chromosome. A healthy woman, whose mother, like her, was healthy, and whose father was a hemophiliac, married a man suffering from hemophilia. What kind of offspring can be expected from this marriage (relative to the disease in question)? When solving this problem, use a very common form of depicting sex chromosomes: X chromosome - dash (-); Y chromosome - half arrow ().
Problem No. 4
The gene responsible for the development of such a trait as hypertrichosis (hair growth on the edge of the earlobe) is one of the few recessive genes localized on the Y chromosome. If a man with hypertrichosis marries a woman who, naturally, does not have hypertrichosis, then what is the real chance of having children with hypertrichosis in this family: boys? Girls?
Problem No. 5
A woman is incredibly excited about the information she accidentally received from “well-wishers” about the secret of her husband’s family. It turned out that her husband, and his brothers, and their father - all of them in early childhood went through the surgical department of the Central District Hospital of their hometown, where each of them underwent the same type of operation to eliminate webbedness (the webbing between the index and middle fingers). And although all these men invariably successfully got rid of this birth defect and tried to enthusiastically convince the woman how painless and easy it was, the woman turned to doctors for advice. What will children born from one of the representatives of this at least strange “webbed” family look like: boys? Girls?
References
1. Dymshits G.M., Sablina O.V., Vysotskaya L.V. and etc.
Biology. General biology. Workshop for students of grades 10-11 of general education organizations. Profile level.
2. "General biology: Textbook for grades 10-11" Ed. D.K. Belyaeva and others 3. Biology. General biology. 10-11 grade. Kamensky A.A., Kriksunov E.A., Pasechnik V.V. M.: Bustard, 2005. - 367 With.
3. Pugovkin M.I. Workshop on general biology, Education, 2002
4.I.N. Ponomareva, O.A. Kornilova, T.E. Loshilina"Biology. Grade 10. A basic level of". M., ed. Ventana-Graf Center, 2010
5. I.N. Ponomareva, O.A. Kornilova, T.E. Loshilina, P.V. Izhevsky “Biology. Grade 11. A basic level of". M., ed. Ventana-Graf Center, 2010
6. E.A. Kriksunov, A.A. Kamensky, V.V. Beekeeper: “General biology. 10-11 grades.” Textbook for educational institutions - M., Bustard. 2005.
7. T.A. Kozlova. Methodological guide to the textbook: E.A. Kriksunov, A.A. Kamensky, V.V. Beekeeper: “General biology. 10-11 grades.” - M., Bustard. 2005
8. S.E. Mansurova Workshop in general biology, grades 10-11, M., Vlados, 2006
9. Shishkanskaya N.A. Genetics and selection, Saratov, Lyceum, 2005
10. Journal “Biology at school”.
Back forward
Attention! Slide previews are for informational purposes only and may not represent all the features of the presentation. If you are interested in this work, please download the full version.
Introduction
An important role in the study of biology at school is played by laboratory work, which contributes to a better assimilation of knowledge and skills of students, contributes to a deeper and more meaningful study of biology, the formation of practical and research skills, the development of creative thinking, the establishment of connections between theoretical knowledge and practical human activities, and facilitates understanding factual material.
An educational experiment has enormous potential for the comprehensive development of students’ personalities. The experiment includes not only the source of knowledge, but also the method of finding it, familiarization with the primary skills of studying natural objects. During the experiment, students gain an understanding of the scientific method of cognition.
Methodical manual “Laboratory workshop. Biology. 5th grade” is intended for organizing research activities of schoolchildren during biology lessons in the 5th grade. The list of laboratory works presented in the methodological manual corresponds to the content of the textbook “Biology” for the 5th grade of general education institutions (authors: I.N. Ponomareva, I.V. Nikolaev, O.A. Kornilova), which opens a line of biology textbooks for primary schools and included in the “Algorithm for Success” system. The textbook does not exactly correspond the paragraphs to the number of hours allocated for their study. Therefore, fewer paragraphs allow the teacher to use the remaining time to conduct laboratory work.
When conducting laboratory work, health-saving technologies, problem-based learning, and development of research skills are used. During practical classes, students develop such universal learning actions as:
- educational – carry out research activities;
- regulatory – check your actions against the goal and, if necessary, correct errors;
- communicative – listen and hear each other, express your thoughts with sufficient completeness and accuracy in accordance with the tasks and conditions of communication.
In the development of practical classes, a problematic question is posed to schoolchildren, the planned results and the necessary equipment are indicated. Each development has instructions for conducting laboratory work. Before performing laboratory work, it is important to familiarize students with the requirements for their execution ( Annex 1), with safety rules when performing laboratory work ( appendix 2), with rules for making drawings of natural objects ( Appendix 3).
For visual accompaniment of practical classes, an electronic presentation is attached to this manual ( presentation).
Laboratory work No. 1 “Study of the structure of magnifying devices”
Planned results: learn to find parts of a magnifying glass and microscope and name them; follow the rules for working in the office and handling laboratory equipment; use the text and pictures of the textbook to complete laboratory work.
Problematic question: how did people learn about the existence of single-celled organisms in nature?
Topic: “Study of the structure of magnifying devices.”
Goal: study the device and learn how to work with magnifying devices.
Equipment: hand magnifying glass, microscope, watermelon fruit tissue, ready-made microspecimen of camellia leaf.
Progress
Exercise 1
1. Examine a hand-held magnifying glass. Find the main parts (Fig. 1). Find out their purpose.
Rice. 1. Structure of a hand-held magnifying glass
2. Examine the flesh of the watermelon with the naked eye.
3. Examine pieces of watermelon pulp under a magnifying glass. What is the structure of watermelon pulp?
Task 2
1. Examine the microscope. Find the main parts (Fig. 2). Find out their purpose. Get acquainted with the rules of working with a microscope (p. 18 of the textbook).
Rice. 2. Structure of the microscope
2. Examine the finished microslide of a camellia leaf under a microscope. Practice the basic steps of using a microscope.
3. Draw a conclusion about the importance of magnifying devices.
Task 3
1. Calculate the total magnification of the microscope. To do this, multiply the numbers indicating the magnification of the eyepiece and objective.
2. Find out how many times the object you are considering can be magnified using a school microscope.
Laboratory work No. 2 “Introduction to plant cells”
Problematic question: “How is the cell of a living organism structured?”
Instruction card for performing laboratory work for students
Topic: “Introduction to plant cells.”
Purpose: to study the structure of a plant cell.
Equipment: microscope, pipette, slide and cover glass, tweezers, dissecting needle, part of an onion, ready-made microslide of a camellia leaf.
Progress
Exercise 1
1. Prepare a microslide of onion skin (Fig. 3). In order to prepare a microslide, read the instructions on p. 23 textbooks.
Rice. 3. Preparation of a microslide of onion skin
2. Examine the preparation under a microscope. Find individual cells. Look at the cells at low magnification and then at high magnification.
3. Draw the cells of the onion skin, indicating in the drawing the main parts of the plant cell (Fig. 4).
1. Cell wall
2. Cytoplasm
3. Vacuoles
Rice. 4. Onion skin cells
4. Draw a conclusion about the structure of a plant cell. What parts of the cell were you able to see under the microscope?
Task 2
Compare onion skin cells and camellia leaf cells. Explain the reasons for the differences in the structure of these cells.
Laboratory work No. 3 “Determination of seed composition”
Planned results: learn to distinguish the main parts of a plant cell; follow the rules for handling laboratory equipment; use the text and pictures of the textbook to complete laboratory work.
Problematic question: “How can you find out what substances are part of a cell?”
Instruction card for performing laboratory work for students
Topic: “Determination of seed composition.”
Purpose: to study methods for detecting substances in plant seeds, to study their chemical composition.
Equipment: a glass of water, a pestle, an iodine solution, gauze and paper napkins, a piece of dough, sunflower seeds.
Progress
Exercise 1
Find out what organic substances are included in plant seeds using the following instructions (Fig. 5):
1. Place a piece of dough on cheesecloth and make a bag (A). Rinse the dough in a glass of water (B).
2. Open the bag of rinsed dough. Test the dough by touch. The substance that remains on the gauze is gluten or protein.
3. Add 2-3 drops of iodine solution (B) to the cloudy liquid formed in the glass. The liquid turns blue. This proves the presence of starch in it.
4. Place sunflower seeds on a paper towel and crush them using a pestle (D). What appeared on the paper?
Rice. 5. Detection of organic substances in plant seeds
5. Draw a conclusion about what organic substances are included in the seeds.
Task 2
Fill out the table “The importance of organic substances in the cell” using the text “The role of organic substances in the cell” on p. 27 textbooks.
Laboratory work No. 4 “Acquaintance with the external structure of a plant”
Planned results: learn to distinguish and name parts of a flowering plant; sketch a diagram of the structure of a flowering plant; follow the rules for handling laboratory equipment; use the text and pictures of the textbook to complete laboratory work.
Problem question: “What organs does a flowering plant have?”
Instruction card for performing laboratory work for students
Topic: “Acquaintance with the external structure of a plant.”
Purpose: to study the external structure of a flowering plant.
Equipment: hand magnifying glass, herbarium of a flowering plant.
Progress
Exercise 1
1. Examine a herbarium specimen of a flowering plant (meadow cornflower). Find the parts of a flowering plant: root, stem, leaves, flowers (Fig. 6).
Rice. 6. Structure of a flowering plant
2. Draw a diagram of the structure of a flowering plant.
3. Draw a conclusion about the structure of a flowering plant. What are the different parts of a flowering plant?
Task 2
Look at the images of horsetail and potatoes (Fig. 7). What organs do these plants have? Why is horsetail classified as a spore plant, and potatoes as a seed plant?
Horsetail Potato
Rice. 7. Representatives of different groups of plants
Laboratory work No. 5 “Observation of the movement of animals”
Planned results: learn to examine single-celled animals under a microscope at low magnification; follow the rules for handling laboratory equipment; use the text and pictures of the textbook to complete laboratory work.
Problematic question: “What is the importance for animals of their ability to move?”
Instruction card for performing laboratory work for students
Topic: “Observing the movement of animals.”
Target: get to know the ways animals move.
Equipment: microscope, slides and coverslips, pipette, cotton wool, glass of water; ciliate culture.
Progress
Exercise 1
1. Prepare a microslide with a culture of ciliates (p. 56 of the textbook).
2. Examine the microscopic specimen under a low magnification microscope. Find the ciliates (Fig. 8). Observe their movement. Note the speed and direction of movement.
Rice. 8. Ciliates
Task 2
1. Add a few crystals of table salt to a drop of water with ciliates. Observe how ciliates behave. Explain the behavior of ciliates.
2. Draw a conclusion about the importance of movement for animals.
Literature
- Aleksashina I.Yu. Natural science with basics of ecology: 5th grade: practical. works and their implementation: book. for the teacher / I.Yu. Aleksashina, O.I. Lagutenko, N.I. Oreshchenko. – M.: Education, 2005. – 174 p.: ill. – (Labyrinth).
- Konstantinova I.Yu. Lesson developments in biology. 5th grade. – 2nd ed. – M.: VAKO, 2016. – 128 p. - (To help the school teacher).
- Ponomareva I.N. Biology: 5th grade: methodological manual / I.N. Ponomareva, I.V. Nikolaev, O.A. Kornilov. – M.: Ventana-Graf, 2014. – 80 p.
- Ponomareva I.N. Biology: 5th grade: a textbook for students of general education organizations / I.N. Ponomareva, I.V. Nikolaev, O.A. Kornilov; edited by I.N. Ponomareva. – M.: Ventana-Graf, 2013. – 128 p.: ill.