The specific function of light energy in the process of photosynthesis is to, a) reduce carbon dioxide b) synthesise glucose, c) activate chlorophyll d) split water molecule, 8. It is next boiled in methylated spirit to (2) ……………. (d) Would you take any step before starting the experiment? Thus, the release of CO2 cannot be demonstrated. Photosynthesis occurs in plants and some bacteria. Complete the following food chains by writing the names of appropriate organisms in the blanks: (ii) Grass/Corn → Mouse → Snake → Peacock. Some of this oxygen may be used in respiration in the leaf cells, but the major portion of it is not required and it diffuses out into the atmosphere through the stomata. Oxygen is the element which all the organisms 2-4 and even 5 are getting from No. How would you demonstrate that green plants release oxygen when exposed to light? The appearance of a blue-black colour on the leaf is indicative of the presence of starch. In every period of twenty-four hours, plants are subjected to a regular cycle change in light intensity, and the rate of photosynthesis increases from dawn to midday and declines as dusk approaches. These notes are totally based on latest Biology textbook of ICSE Board. / The role of sunlight in photosynthesis is being investigated. ICSE Solutions for Class 10 Biology – Photosynthesis ICSE SolutionsSelina ICSE Solutions APlusTopper.com provides ICSE Solutions for Class 10 Biology Chapter 5 Photosynthesis for ICSE … Photosynthesis is the only biological process which releases oxygen into the atmosphere. (d) A plant and a snail are kept in test tube B. Oxygen is released as a by-product. Short Questions. So the various experiments on photosynthesis can be carried out effectively. To get purified air in her room she kept some of the plants in a closed room, it leaves turned pale in colour after some days. Free PDF download of Class 10 Biology Chapter 6 - Photosynthesis: Provider of Food for All Revision Notes & Short Key-notes prepared by our expert Biology teachers as per CISCE guidelines. 4. Author Rating. State any four differences between photosynthesis and respiration. The potted plant was then placed in sunlight for a few hours. (a)The hydrogen ions (H+) are picked up by a compound NADP (Nicotinamide adenine dinucleotide phosphate) to form NADPH. Answer : Photolysis in photosynthesis is the splitting of water molecules into hydrogen ions and hydroxyl ions in the presence of chlorophyll and light. Given below is the diagram of an experimental set-up: (a) What is objective of this experiment? Describe the main chemical changes which occur during photosynthesis in: Photosynthesis increases with the light intensity up to a certain limit only, and then it gets stabilised at the point. No, the experiment will not work satisfactorily because, as mentioned in the above statement carbon dioxide is very important in the photosynthesis. Green plants (producers) use carbon dioxide of the air to produce carbohydrates and release oxygen to the atmosphere. (g) Photosynthesis is considered as a process supporting all life on earth. A series of chemical reactions occur in very quick succession, initiated by light and therefore, the phase is called the photochemical phase. Describe the main chemical changes which occur during photosynthesis in: The light reaction occurs in two main steps: (1) Activation of chlorophyll – On exposure to light energy, chlorophyll becomes activated by absorbing photons. (c) What is the purpose of keeping a snail in test-tube B? If a plant is kept in bright light all the 24 hours for a few days, the dark reaction (biosynthetic phase) will continue to occur because these set of reactions are independent of light and it occurs simultaneously with the light-dependent reaction. (4) The carbon dioxide is used and released in the process of photosynthesis. (3) Photosynthesis consists of two stages light reaction and dark reaction. How do non-green plants such as fungi and bacteria obtain their nourishment? Fungi and bacteria break down the organic matter to obtain the nourishment and they release carbon dioxide back in the atmosphere. You can watch our video lessons to understand different types of transpiration such as lenticular transpiration, cuticular transpiration and stomatal transpiration. (b) Name any one organism that could be shown at No.5. (b) What phenomenon do the think arrows A and B indicate respectively? Our specialist teachers have answered these exercises to help you with your exam preparation to achieve good marks in the subject. (a) Photosynthesis releases bubbles of oxygen. The region, which contains starch, turns blue-black and the region, which does not contain starch, turns brown. (a) Guard cells are cells surrounding each stoma. Most leaves have the upper surface more green and shiny than the lower one. Download pdf of Class 10 Chapter 6 in their respective links. Solution:-. (e) Phloem tissue in Leaf Veins Solution:-. Non-green plants such as fungi and bacteria obtain their nourishment from decaying organic matter in their environment. Light reactions take place during the first stage of photosynthesis. The potted plant was kept in the dark for 24 hours. (a) Fill up the gaps, in blank spaces (1-4), by writing the names of the correct items. (d) Why does test-tube B have more bubbles of oxygen? Explain briefly the role of the following structures in this process. (d) Would you take any step before starting the experiment? During this period, all the starch will be removed from the leaves and stored in the storage organs. (c) The compound which stores energy in the cells. The presence of starch is indicated by a blue-black colour. Are the following statements true or false? (1) The leaf is boiled in water for a minute to kill the cells. b. (e) The starting point of carbon cycle is the release of CO2 by animals during respiration. (c) Mesophyll cells The rate of photosynthesis is not affected by, a) breaking down water into hydrogen and oxygen. (g) Photosynthesis stops at a temperature of about 35oC. Chloroplasts are cell organelles, situated in the cytoplasm of plant cells. Hence most leaves have the upper surface more green and shiny than the lower one. (a) The site of light reaction in the cells of a leaf is ………… (cytoplasm, stroma, grana), (b) The chemical substance used to test the presence of starch in the cell of a leaf is …………. What aspect of photosynthesis was being investigated? (CaCl2, iodine solution, Benedict solution), (c) Stroma is ground substance in ……………. The raw material for respiration is glucose. It is contained in microscopic cell organelles called chloroplasts. (2) Splitting of water – The absorbed energy is used in splitting the water molecule into hydrogen and oxygen, releasing energy. List of subtopics covered in Selina Solutions Concise Biology Class 10 Chapter 6 Photosynthesis, Your email address will not be published. The male hormone produced by the interstitial cells. (b) The chemical substance used to test the presence of starch in the cell of a leaf is…………… (CaCl2, iodine solution, Benedict solution). Both test-tubes are kept in sunlight. The correct order in a logical sequence with regard to photosynthesis be. The leaves will not show the presence of starch. a) Carbon dioxide is reduced and water is oxidised, b) Water is reduced and carbon dioxide is oxidised, c) Both carbon dioxide and water are oxidised, d) Both carbon dioxide and water are reduced, 7. Respiration results in loss of dry weight of the plants. ATP (Adenosine triphosphate) stores energy in the cells. Thus, we can say that all life owes its existence to chlorophyll. (3) Chemical equation for the process of photosynthesis: The diagram below shows two test-tubes A and B. Test-tube A contains a green water plant. Oxygen is released during photosynthesis. Photosynthesis. 10. 5. The leaf is placed in warm water to soften it. In photosynthesis solar energy (sunlight) is converted to chemical energy and is stored in plants as starch. Solution:-, (e) Green plants are consumers. (c) What alteration(s) will you make in it for obtaining expected result? The absence of starch is indicated by a brown colouration. 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