Investigating factors affecting the rate of photosynthesis
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 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. Skills developed in this inquiry lab are as follows: creating and conducting a controlled experiment, using Bromthymol blue as an indicator for carbon dioxide, creating a data table on which to record data and making observations. Teachers of biology, early career teachers, returning teachers, non-specialist teachers, technicians and teaching assistants will gain from the peer learning and resources available on this course. Increase in mass of the disc is an indication of the extra mass that has been stored in the leaf. Keep the whole apparatus in sunlight. The available mass of carbon dioxide increases with each addition. 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 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.
The loss in weight is measured. I like the idea of students discovering what is used during photosynthesis. The teacher will now demonstrate to students the basic technique that will be used to measure the rate of photosynthesis. One of them contains a plant 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. Coloured filters can be used, but these will affect light intensity by different amounts depending on the colour.
The distances from the lamp to the experiment that I plan to use are 5cm, 10cm, 15cm, 20cm, 25cm and 30cm. Light intensity is the variable being tested, and by moving the lamp closer or further away I will be changing the intensity of the light. Results: The liberated gas is oxygen and it is evolved due to the photolysis of water under the process of photosynthesis. By increasing the use of carbon dioxide by plants, it may help slow global climate change. My results do agree with my prediction to a certain extent, because I predicted that the rate of photosynthesis would increase as the light intensity did because the light provides energy for the reaction, and the more energy the plant has, the faster it will be able to photosynthesise. I tried to release all of the bubbles before the experiment started, but this was not very easy and so some remained, mainly on the edge of the test tube.
Crumb structure is shown to be important. With the help of a sharp cork borer punch out about 10 pieces from the half part of a de-starched leaf, still attached to the plant cork borer should be used against a wooden block, and care should be taken so that large veins are not injured during punching. Another reason that the amount of water must be kept the same is because when plants do not have enough water, they close the stomata, to prevent further water loss. Hypothesis: The greater the light intensity, the greater the rate of photosynthesis and the greater the production of oxygen by plant leaf disks. Chlorophyll absorbs the energy of sunlight. A simple Tullgren funnel is used to drive arthropods from the soil.
Biology Practical for Class 11 Practical Examination 2018
The leaf part receiving red light is darkly-stained while that receiving blue light is next in the order. Second darkly-stained region is the blue region of the leaf. 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 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. In the black paper or black tin foil disc of the screen, cut a pattern of some kind like P and fix it on the screen. But instead of adding sodium bicarbonate, keep the whole apparatus in sunlight and shade with definite intervals and note the number of bubbles in a definite time. The lesson begins with an assessment of student preconceptions and ends with students reflecting on their new understandings.
The experiment should also be carried out in one session, less than two hours, so that the plant does not use up a significant percentage of the carbon dioxide. This indicates that photosynthesis has taken place in this region also, but it happened at a lower rate than that of red region. One dish of leaf disks was placed in the dark, one dish under the room lights, and one dish 25 cm from a light source. It does, though tend to break apart very easily, and fish may eat it very quickly. The students can be allocated to investigate a particular factor that affects the rate of photosynthesis, or they can choose from this list, or they can develop their own ideas. Another problem was that there were air bubbles trapped in the funnel and on the test tube, from when I had set the equipment up. All students will be guided to use this technique.
Investigating Photosynthesis: Discovering what plants need for photosynthesis
Give students time to design experiment and do a trial run. Put these punched pieces in an oven at 86°C and determine their dry weight. It is the process of converting light energy into chemical energy and storing it in the bonds of sugar of the organism. As this is done, the oxygen is being removed from the spongy layer of the leaf and the. Place the beaker, along with the leaves, in bright light for at least four hours, and then wipe off as much vaseline as possible with a soft rag.
In order to make sugar plants require only the following: Light energy, Water, and Carbon Dioxide. Photosynthesis is the process by which plants take carbon dioxide from the atmosphere, add water, and use the energy of sunlight to produce sugar. Do not copy or use anything from these pages without written permission. The light provides energy for the reaction to take place, and so if a plant has more light then it should have more energy to use in the reactions, and the rate of reaction should become faster. Fix a de-starched leaf below the glass top of the box and keep the apparatus in sunlight Fig.
