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Experimental work in biology: Biology experiments to download

Beneath the description of each experiment you will find links from which you can open or download the experiments in Word format, and a link from which you can download the group of documents in a zip file. If you do not have Microsoft Word installed you can download Word Viewer free here. If you do not have WinZip installed you can download a free trial here. To download whole sets of experiments in zip files see the links to the right.

See also: Supplementary experiments   Introduction

Food tests

Reagent for food tests and enzymes
Reagent for food tests and enzymes

1 Test for starch
Using iodine solution
1. Test for starch

2 Test for glucose
Using Benedict’s reagent
2. Test for glucose

3 Test for protein
The biuret reaction
3. Test for protein

4 Test for lipid
The emulsion test
4. Test for fats

5 How sensitive is the starch test?
A serial dilution of starch solution is tested with iodine
6 Testing food for starch
Samples of different foods are tested with iodine solution
7 A comparison of vitamin C content
The volumes of fruit juices needed to decolourise DCPIP are measured Back to top

Enzymes

Reagent for food tests and enzymes
Reagent for food tests and enzymes

1 Effect of amylase on starch

Disappearance of blue colour from starch solution plus iodine

2 Effect of temperature
Timing the disappearance of the blue colour at different temperatures
3 Effect of pH
Timing the disappearance of blue colour at different pH values
4 Catalase
Liver and yeast are used to decompose hydrogen peroxide
5 Effect of enzyme concentration
Increasing strengths of urease are used to produce ammonia from urea
6 Enzymes in maize fruits
Maize fruits are sectioned and placed on starch-agar. Iodine solution reveals clear areas of starch-agar under the fruit Back to top

Respiration

1 Oxygen uptake
The inability of air from germinating seeds to support combustion
2 Carbon dioxide output
The gas from germinating seeds turns limewater milky
3 Exhaled air (1)
The last fraction of exhaled air will not support combustion
4 Exhaled air (2)
Atmospheric air and exhaled air are bubbled simultaneously through limewater
5 Respiration in living organisms
A manometer reveals uptake of oxygen by germinating seeds
6 Anaerobic respiration
The gas produced by a yeast suspension from which air is excluded turns limewater milky
7 Energy release during respiration
Germinating wheat is packed into vacuum flasks to see if there is any rise in temperature over a few days
8 Changes in mass during germination
Wheat is germinated for about two weeks. Samples are taken at 2-day intervals, dried and weighed
9 Measuring the uptake of oxygen
The respirometer is used to measure the uptake of oxygen in living organisms
10 Temperature effect on respiration
The oxygen uptake of living organisms at different temperatures is measured with the respirometer
11 Oxygen uptake in blowfly larvae
The oxygen uptake of blowfly larvae is measured over a 20 minute period. The air in the respirometer is then renewed and the rate of oxygen uptake compared
12 The effect of temperature on fermentation rate
The respirometer is used to measure the rate of carbon dioxide production from a suspension of yeast in glucose solution at different temperatures Back to top

Photosynthesis

Introduction to experiments on Photosynthesis
1 Production of gas by pondweed
Bubbles escape from the cut stems of Canadian pondweed when illuminated
2 Testing a leaf for starch
The technique of killing and decolourising a leaf and testing it with iodine solution
3 The need for light
Light is excluded from part of a leaf which is tested for starch after a period of illumination
4 The need for chlorophyll
A variegated leaf is tested for starch after a period of illumination
5 The need for carbon dioxide
A potted plant is enclosed in a plastic bag from which carbon dioxide has been absorbed.one of its leaves is tested for starch after a period of illumination
6 Collecting the gas from pondweed
The cut end of a Canadian pondweed shoot is placed in a water-filled test tube. The gas is collected and tested for oxygen
7 Gaseous exchange in leaves
Leaves are enclosed in test-tubes containing hydrogencarbonate indicator. The tubes are illuminated or darkened
8 Gaseous exchange in pond-weed
Leaves are enclosed in test-tubes containing hydrogencarbonate indicator. The tubes are illuminated or darkened
9 The need for mineral elements
Wheat seedlings are grown for two weeks in water cultures lacking essential elements

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Diffusion

1 Diffusion in gases
Diffusion of ammonia is observed in a glass tube using litmus paper
2 Diffusion in liquid
Diffusion of methylene blue through gelatine is observed
3 Diffusion and size
Different size blocks of gelatine mixed with cresol red are immersed in acid to see the progress of the acid through the gelatine
4 Diffusion through a membrane
A dialysis tube filled with starch solution is immersed in iodine solution
5 Control of diffusion
Beetroot discs are heated at increasing temperatures to illustrate the control on diffusion by the cell membrane
6 Two-way diffusion
Ammonia diffuses into gelatine coloured with cresol red which diffuses in the opposite direction Back to top

Osmosis

1 Osmosis
An osmometer made from dialysis tubing and a capillary tube shows osmosis happening
2 Selective permeability
Dialysis tubing containing starch and glucose solutions is immersed in water
3 Turgor
A length of dialysis tube is partly filled with a syrup solution and immersed in water
4 Turgor in plant tissue
Strips of dandelion stalk are immersed in salt solutions of differing strength and changes in curvature observed
5 Turgor in potato tissue
Cylinders of potato tissue are immersed in solutions of differing strength and changes in length are measured
6 Root pressure
Glass tubes are fitted to the cut branches of a potted plant. The levels of liquid in each tube are observed
7 Stomatal movements
Leaf epidermis is irrigated with salt solution to see its effect on guard cells
8 Plasmolysis
Red epidermis from rhubarb petiole is irrigated with sucrose solution and observed under the microscope
9 Surface area and osmosis
Potato cubes with equal volume but different surface area are immersed in water and weighed Back to top

Human senses

1 Reaction time
The distance a vertical ruler falls before being gripped is converted to a time interval
2a The blind spot (1)
A dot seems to disappear when its image falls on the blind spot
2b The blind spot (2)
A gap in a line is 'filled in' when its image falls on the blind spot
3 Inversion of the image
When a pin is viewed via a pinhole in front of the pin, its image appears to be inverted
4a The iris diaphragm (1)
The iris is observed to reduce the size of the pupil when the eye is exposed to light
4b The iris diaphragm (2)
(Broca's pupillometer) A pattern of pinholes appears to change when one eye is exposed to light
5 Retinal capillaries
By moving a pinhole about in front of the eye, an image of retinal capillaries appears
6a Binocular vision: eye dominance
A pencil lined up with a window frame appears to 'jump' when the dominant eye is closed
6b Binocular vision: double vision
Slight pressure on one eyeball causes a single object to appear as a double image
7 Judgement of distance
The space sequence of coloured pinheads is judged using either one or both eyes
8 Eye and hand co-ordination
A star pattern is traced while looking in a mirror
9 Perception
Two shapes are observed, and demonstrate that the brain makes an interpretation of the image
10 Sensitivity of the skin to touch
Different areas of skin are tested with light touch to see if there are differences in reponse
11 Recognition of separate stimuli
(Spatial discrimination) Different areas of skin are tested with a 'hairpin' to see if they can discriminate a double touch from a single touch
12 Sensitivity to temperature
One finger is placed in hot water and another in cold water. Both are then placed in warm water and the sensations compared
13 Location of stimuli
A marble is rolled between crossed fingers to give the sensation of two marbles

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Transport in plants

1 Uptake and evaporation in leaves
The uptake of water by single leaves is measured after coating either, neither or both surfaces with Vaseline
2 Uptake of water by shoots
The uptake of water by a shoot is measured, using a potometer
3 Rates of transpiration
The potometer is used in different conditions to compare rates of uptake by the shoot
4 Rate of transpiration and water uptake
By weighing the shoot and potometer, the uptake and loss of water are compared
5 Uptake of water by an uprooted plant
The potometer is modified to accept a whole plant rather than a cut shoot
6 Conditions affecting evaporation
A simple atmometer is used to investigate the effects of different atmospheric conditions on the rate of evaporation
7 Water tension in the stem
The lower end of the potometer is placed in mercury, which is pulled up the capillary by the transpiration force
8 Pathways for gases in a leaf
A leaf is immersed in hot water to expand and force out any air inside it
9 Evaporation from the leaf surface
Evaporation from the upper and lower leaf surface is compared and correlated with the distribution of stomata
10 To collect and identify the product of transpiration
The shoot of a plant is enclosed in a plastic bag. The liquid which condenses is identified
11 To trace the path of water through a shoot
Shoots are placed in a dye in order to investigate the route it takes through the stem and leaves
12 Conducting pathways through the shoot
A syringe is used to force air through a shoot held under water, Air bubbles show the continuity of the vessels
13 Measuring the transpiration rate of a potted plant
Two potted plants, one in sunlight and one in shadow are weighed at intervals
14 Measuring the transpiration rate of an uprooted plant
Two flasks of water are weighed at intervals. One of them contains a plant

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Germination and tropisms

Introduction
1 The need for oxygen
Cress seeds are sown on moist cotton wool in 2 flasks one of which contains pyrogallic acid and sodium hydroxide
2 Effect of temperature
Maize fruits are germinated in moist blotting paper at different temperatures
3 The need for water
Seeds are left in moist, dry and waterlogged conditions for a week
4 The role of cotyledons
Runner bean embryos attached to varying amounts of cotyledon are germinated on moist blotting paper in jars
5 Use of food reserves in germination
Coleoptiles and endosperm of cereal seedlings and grains are tested for starch and sugar
6 Geotropism in radicles
Pea seedlings are pinned to a clinostat, or a stationary base, with their radicles horizontal
7 The region of growth and response in radicles
Radicles are marked with equidistant lines and left horizontally or vertically for two days
8 Region of detection and response to one-sided gravity in radicles
Different lengths of root tip are excised to see if the radicles still grow and respond to gravity
9 The effect of one-sided lighting on shoots
Hypocotyls of sunflower seedlings are marked and illuminated from one side
10 The effect of one-sided lighting on cress seedlings
Cress seedlings, some of which are decapitated, are illuminated from the side or from above
11 The region of detection and response to one-sided lighting in coleoptiles
Coleoptiles of wheat seedlings, some covered by foil caps, some decapitated, are illuminated from the side
12 Effect of indoleacetic acid on coleoptiles
Indoleacetic acid in lanolin is applied to intact coleoptiles. A control is conducted with plain lanolin
13 The effect of indoleacetic acid on wheat coleoptiles
The tips of the coleoptiles of wheat seedlings are removed and IAA in lanolin applied. Controls are conducted with plain lanolin, untreated cut coleoptiles and intact coleoptiles
14 Effect of indoleacetic acid on maize coleoptiles
Indoleacetic acid in lanolin is applied to one side of a maize coleoptile. A control with plain lanolin is included
15 The effect of light on shoots
Pea seedlings are grown for a week in light or darkness and their shoots compared
16 Respiratory activity in maize seedlings
Maize grains and seedlings are immersed in tetrazolium chloride solution for 30 minutes Back to top

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