{"id":15860,"date":"2024-02-12T16:32:11","date_gmt":"2024-02-12T11:02:11","guid":{"rendered":"https:\/\/icsesolutions.com\/?p=15860"},"modified":"2024-02-13T10:48:17","modified_gmt":"2024-02-13T05:18:17","slug":"selina-icse-solutions-class-10-biology-photosynthesis-provider-food","status":"publish","type":"post","link":"https:\/\/icsesolutions.com\/selina-icse-solutions-class-10-biology-photosynthesis-provider-food\/","title":{"rendered":"Selina Concise Biology Class 10 ICSE Solutions Photosynthesis: Provider of Food for All"},"content":{"rendered":"

Selina Concise Biology Class 10 ICSE Solutions Photosynthesis: Provider of Food for All<\/span><\/h2>\n

APlusTopper.com provides step by step solutions for Selina Concise ICSE Solutions for Class 10 Biology Chapter 6 Photosynthesis: Provider of Food for All. You can download the Selina Concise Biology ICSE Solutions for Class 10 with Free PDF download option. Selina Publishers Concise Biology for Class 10 ICSE Solutions all questions are solved and explained by expert teachers as per ICSE board guidelines.<\/p>\n

Download Formulae Handbook For ICSE Class 9 and 10<\/a><\/p>\n

ICSE Solutions<\/a>Selina ICSE Solutions<\/a><\/p>\n

Selina ICSE Solutions for Class 10 Biology Chapter 6 Photosynthesis: Provider of Food for All<\/strong><\/p>\n

Exercise 1<\/strong><\/span><\/p>\n

Solution A.1.<\/strong><\/span>
\nb) glucose formed in photosynthesis soon gets converted into starch<\/p>\n

Solution A.2.<\/strong><\/span>
\nb) twelve<\/p>\n

Solution A.3.<\/strong><\/span>
\nb) humidity<\/p>\n

Solution A.4.<\/strong><\/span>
\nc) trapping light energy<\/p>\n

Solution A.5.<\/strong><\/span>
\na) continue to live, but will not be able to store food<\/p>\n

Solution A.6.<\/strong><\/span>
\na) Carbon dioxide is reduced and water is oxidised<\/p>\n

Solution A.7.<\/strong><\/span>
\nc) activate chlorophyll<\/p>\n

Solution A.8.<\/strong><\/span>
\nd) ensure that the leaves are free from starch<\/p>\n

Solution A.9.
\n<\/strong><\/span>a) CO2<\/sub><\/p>\n

Solution B.1.<\/strong><\/span>
\n(a) Producers \/ Autotrophs
\n(b) Chloroplasts
\n(c) ATP (Adenosine triphosphate)
\n(d) Glucose
\n(e) Green plants
\n(f) Carbon dioxide dissolved in water
\n(g) Stroma
\n(h) Phloem<\/p>\n

Solution C.1.<\/strong><\/span><\/p>\n

(a)<\/p>\n\n\n\n\n
Respiration<\/strong><\/td>\nPhotosynthesis<\/strong><\/td>\n<\/tr>\n
The gas released during respiration is carbon dioxide.<\/td>\nThe gas released during photosynthesis is oxygen.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(b)<\/p>\n\n\n\n\n
Light Reaction<\/strong><\/td>\nDark Reaction<\/strong><\/td>\n<\/tr>\n
Hydrogen and oxygen are produced here, along with release of electrons, which converts ADP into ATP.<\/td>\nGlucose is the main product formed during dark reaction.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(c)<\/p>\n\n\n\n\n
Producers<\/strong><\/td>\nConsumers<\/strong><\/td>\n<\/tr>\n
Producers show autotrophic mode of nutrition i.e. they are able to produce their own food from basic raw materials.
\nFor example: green plants<\/td>\n		\n

Consumers show heterotrophic mode of nutrition i.e. they depend directly or indirectly on the producers for their food.
\nFor example: Animals<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(d)<\/p>\n\n\n\n\n
Grass<\/strong><\/td>\nGrasshopper<\/strong><\/td>\n<\/tr>\n
Green grass being a producer is capable of producing its own food by photosynthesis.<\/td>\nGrasshopper is a primary consumer (herbivore) and directly feeds on producers like grass.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(e)<\/p>\n\n\n\n\n
Chlorophyll<\/strong><\/td>\nChloroplast<\/strong><\/td>\n<\/tr>\n
Chlorophyll is the green pigment present in cell organelles called chloroplasts.<\/td>\nChloroplasts are cell organelles, situated in the cytoplasm of plant cells. They are present mainly in the mesophyll cells and in the guard cells of stomata.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Solution C.2.<\/strong><\/span>
\n(a) False
\nCorrect Statement: Dark reaction of photosynthesis is independent of light and occurs simultaneously with light reaction.<\/p>\n

(b) True<\/p>\n

(c) False
\nCorrect Statement: Starch produced in a leaf is stored temporarily in the leaf until the process of photosynthesis. At night it is converted back into soluble sugar and translocated to different part of the body either for the utilization or for the storage.<\/p>\n

(d) True<\/p>\n

(e) False
\nCorrect Statement: Green plants are producers.<\/p>\n

(f) False
\nCorrect Statement: Respiration results in loss of dry weight of the plants.<\/p>\n

(g) False
\nCorrect Statement: Photosynthesis stops at a temperature of above 40oC.<\/p>\n

(h) True
\n(i) True
\n(j) True<\/p>\n

Solution C.3.<\/strong><\/span>
\n(a) grana
\n(b) iodine solution
\n(c) chloroplast
\n(d) Calvin cycle
\n(e) Sucrose<\/p>\n

Solution C.4.<\/strong><\/span><\/p>\n

(a) False
\nPhotosynthesis increases with the light intensity up to a certain limit only and then it gets stabilized.<\/p>\n

(b) False
\nThe atmospheric temperature is an important external factor affecting photosynthesis. The rate of photosynthesis increases up to the temperature 35o<\/sup>C after which the rate falls and the photosynthesis stops after 40o<\/sup>C.<\/p>\n

(c) False
\nIce cold water will hamper the process of photosynthesis in the immersed leaf, even if there is sufficient sunshine because the temperature is an important factor for the rate of photosynthesis.<\/p>\n

(d) False
\nFor destarching, the potted plant can kept in a dark room for 24-48 hours.<\/p>\n

(e) False
\nThere is no start point or end point in the carbon cycle, the carbon is constantly circulated between the atmosphere and the living organisms.<\/p>\n

(f) False
\nIf 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 the dark reaction is independent of light and it occurs simultaneously with the light dependent reaction.<\/p>\n

(g) True<\/p>\n

Solution C.5.<\/strong><\/span>
\nPhotons, grana, water molecules, hydrogen and hydroxyl ions, oxygen<\/p>\n

Solution C.6.<\/strong><\/span><\/p>\n\n\n\n\n\n\n\n\n
Photosynthesis<\/strong><\/td>\nRespiration<\/strong><\/td>\n<\/tr>\n
Carbon dioxide is used up and oxygen is released.<\/td>\nOxygen is used up and carbon dioxide is released.<\/td>\n<\/tr>\n
Photosynthesis occurs in plants and some bacteria.<\/td>\nRespiration occurs in all living organisms.<\/td>\n<\/tr>\n
Photosynthesis results in gain of dry weight of the plants.<\/td>\nRespiration results in loss of dry weight of the plants.<\/td>\n<\/tr>\n
Glucose is produced which is utilized by the plants.<\/td>\nGlucose is broken down to obtain energy.<\/td>\n<\/tr>\n
The raw materials for the photosynthesis are water, carbon dioxide and sunlight.<\/td>\nThe raw material for respiration is glucose.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(Any 4)<\/p>\n

Solution C.7.<\/strong><\/span>
\nOxygen is released during photosynthesis. 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. However, in a sense, even this oxygen is not a waste because all organisms require it for their existence including the plants.<\/p>\n

Solution C.8.<\/strong><\/span>
\nThe presence of starch is regarded as evidence of photosynthesis. Hence before starting an experiment on photosynthesis, the plant should be placed in the dark for 24-48 hours to destarch the leaves. During this period, all the starch from the leaves will be sent to the storage organs and the leaves will not show the presence of starch. So the various experiments on photosynthesis can be carried out effectively.<\/p>\n

Solution C.9.<\/strong><\/span>
\nDestarching means removal of starch. Destarching is carried out so that all the starch from the leaves will be sent to the storage organs. Hence all the leaves will not show the presence of starch and photosynthesis can be studied. Destarching ensures that any starch present after the experiment has been formed under experimental conditions.<\/p>\n

Solution C.10.
\n<\/strong><\/span>If a green plant is kept in bright light, it tends to use up all the CO2<\/sub>\u00a0produced during respiration, for photosynthesis. Thus, the release of CO2<\/sub>cannot be demonstrated. Hence, it is difficult to demonstrate respiration as these two processes occur simultaneously.<\/p>\n

Solution C.11.<\/strong><\/span>
\nThe chloroplasts are concentrated in the upper layers of the leaf which helps cells to trap the sunlight quickly. Also the epidermis is covered by a waxy, waterproof layer of cuticle. This layer is thicker on the upper surface than the lower one. Hence most leaves have the upper surface more green and shiny than the lower one.<\/p>\n

Solution C.12.<\/strong><\/span><\/p>\n

    \n
  • Place hydrilla plant (a water plant) in a beaker containing pond water and cover it by a short-stemmed funnel. (Make sure the level of water in the beaker is above the level of the stem of the funnel)<\/li>\n
  • Invert a test tube full of water over the stem of the funnel.<\/li>\n
  • Place the set up in the sun light for a few hours.<\/li>\n<\/ul>\n

    Observation:<\/strong>
    \nBubbles appear in the stem which rise and are collected in the test tube. When sufficient gas gets collected, a glowing splinter will be introduced in the test tube, which will burst into flames.<\/p>\n

    Inference:<\/strong>
    \nThe splinter glows due the presence of oxygen in the test tube which proves that the gas collected in the test is released by hydrilla during photosynthesis.
    \n\"Selina<\/p>\n

    Solution C.13.<\/strong><\/span><\/p>\n

    (i)\u00a0Light Reaction:\u00a0<\/strong>
    \nThe light reaction occurs in two main steps:<\/p>\n

      \n
    1. Activation of chlorophyll – On exposure to light energy, chlorophyll becomes activated by absorbing photons.<\/li>\n
    2. Splitting of water – The absorbed energy is used in splitting the water molecule into hydrogen and oxygen, releasing energy. This reaction is known as photolysis of water.<\/li>\n<\/ol>\n

      \"Selina
      \nThe fate of H+<\/sup>, e–<\/sup>\u00a0and (O) component are as follows:
      \nThe hydrogen ions (H+<\/sup>) obtained from above are picked up by a compound NADP (Nicotinamide adenine dinucleotide phosphate) to form NADPH.
      \n\"Selina
      \nThe oxygen (O) component is given out as molecular oxygen (O2<\/sub>).
      \n2O\u00a0\u2192\u00a0O2
      \n<\/sub>The electrons (e–<\/sup>) are used in converting ADP into energy rich ATP by adding one inorganic phosphate group Pi<\/sub>.
      \nADP + Pi<\/sub>\u00a0\u2192 ATP
      \nThis process is called photophosphorylation.<\/p>\n

      (ii)\u00a0Dark reaction:<\/strong>\u00a0The reactions in this phase does not require light energy and occur simultaneously with the light reaction. The time gap between the light and dark reaction is less than one thousandth of a second. In the dark reaction, ATP and NADPH molecules (produced during light reaction) are used to produce glucose (C6<\/sub>H12<\/sub>O6<\/sub>) from carbon dioxide. Fixation and reduction of carbon dioxide occurs in the stroma of the chloroplast through a series of reactions. The glucose produced is either immediately used up by the cells or stored in the form of starch.
      \n\"Selina<\/p>\n

      Solution C.14.<\/strong><\/span>
      \nComplete the following food chains by writing the names of appropriate organisms in the blanks:
      \n(i) Grass \u2192 Rabbit. \u2192 Snake \u2192 Hawk
      \n(ii) Grass\/Corn \u2192 Mouse \u2192 Snake \u2192 Peacock<\/p>\n

      Solution C.15.<\/strong><\/span>
      \nNon-green plants such as fungi and bacteria obtain their nourishment from decaying organic matter in their environment. This matter comes from dead animals and plants. Fungi and bacteria break down the organic matter to obtain the nourishment and they release carbon dioxide back in the atmosphere.<\/p>\n

      Solution C.16.
      \n<\/strong><\/span>Chlorophyll is the foundation site for the photosynthesis in green plants. The initiation of photosynthesis takes place when the chlorophyll molecule traps the light energy. The light energy is then converted into chemical energy in the form of glucose using carbon dioxide (CO2<\/sub>) from the atmosphere, and water (H2<\/sub>O) from the soil. All other organisms, directly or indirectly depend on this food for their survival. The starting point of any food chain is always a plant. If green plants were to suddenly disappear, then so would virtually all life on Earth. Thus, we can say that all life owes its existence to chlorophyll.<\/p>\n

      Solution C.17.
      \n<\/strong><\/span>To test the leaf for starch, the leaf is boiled in water\u00a0to kill the cells<\/u><\/b>. It is next boiled in methylated spirit to\u00a0remove chlorophyll<\/u><\/b>. The leaf is placed in warm water to soften it. It is then placed in a dish and\u00a0iodine<\/u><\/b>\u00a0solution in added. The region, which contains starch, turns\u00a0blue-black\u00a0<\/u><\/b>and the region, which does not contain starch, turns\u00a0brown.<\/u><\/b><\/p>\n

      Solution D.1.<\/strong><\/span><\/p>\n

      a. The student wanted to show that sunlight is necessary for photosynthesis. \/ The role of sunlight in photosynthesis is being investigated.<\/p>\n

      b. Yes. The other uncovered leave of the potted plant act as a control.<\/p>\n

      c. Destarching ensures that any starch present after the experiment has been formed under experimental conditions. Therefore, the plant was kept in the dark before the experiment.<\/p>\n

      d.<\/p>\n