10th Class Biology 1st Lesson Nutrition - Food Supplying System Textbook Questions and Answers

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Question 1.Write differences between?
  • Autotrophic nutrition - Heterotrophic nutrition


Autotrophic nutrition Heterotrophic nutrition
1. Organism makes its own food 1. Organism can not makes its own food
2. Food is prepared from C02, water and sunlight 2) Food is prepared from other organism
3. Chlorophyll is required 3. Chlorophyll is Not required
4. It takes place during day time 4. It takes place throughout the day
5. Examples are all green plants and photosynthetic bacteria 5. All animals, Fungi and some bacteria
  • Ingestion - Digestion
  • Answer:

    Ingestion Digestion
    1. Taking in of food into the body through mouth is called ingestion 1. Breaking up of complex molecules of food into simple and small molecules is called digestion
    2. Ingestion does not change the chemical and mechanical structure of food 2. Digestion changes the chemical and mechanical structure of food
  • Light reaction - Dark reaction
  • (OR) Differentiate the reactions that take place in presence of light and the reactions which do not require light in photosynthesis.


    Light reaction Dark reaction
    1. It occurs in the grana of the chloroplast 1. It occurs in the stroma of the chloroplast
    2. It occurs only in the presence of light 2. It occurs in the presence or absence of light
    3. It occurs in the grana of the chloroplast 3. It occurs in the stroma of the chloroplast
    4. Light reaction absorbs oxygen and light energy 4. Dark reaction absorbs only CO2
    5. End products are O2, ATP and NADPH 5. End product is Glucose
    6. Photolysis of water occurs 6. Carbon fixation occurs
    7. First stage of photosynthesis 7. Second stage o: photosynthesis
  • Chlorophyll - Chloroplast
  • Answer:

    Chlorophyll Chloroplast
    1. Chlorophyll is the green coloured pigment present in the chloroplast 1. It is the green coloured plastid enclosed by membranes
    2. It contains one atom of magnesium 2. It consists of 3 membranes
    3. It harvests solar energy and convert into chemical energy 3. It is responsible for enzymatic reactions leading to the synthesis of glucose
    Question 2.Give reasons.
    a) Why photosynthesis is considered as the basic energy source for most of living world?
    (OR) Why can we say that photosynthesis is the basic energy source for the living world?


    • All living organisms constantly need energy to be alive
    • They get energy from the food they eat
    • The food directly or indirectly comes from the green plants through photosynthesis
    • Hence photosynthesis can be considered as the basic energy source for most of living world
    b) Why is it better to call the dark phase of photosynthesis as a light independent phase?


    • The term dark reaction or light independent does not mean that they occur when it is dark at night
    • It only means that the reactions are not depend on light
    • Hence we call the dark phase of photosynthesis as a light independent phase
    c) Why is it necessary to destarch a plant before performing any experiment on photosynthesis?


    • To get better results, it is necessary to destarch a plant before performing any experiment on photosynthesis
    • Because if starch is present it may interfere with the result of the experiment
    d) Why is it not possible to demonstrate respiration in green plants kept in sunlight?


    • We cannot demonstrate an experiment of respiration in green plants kept in sunlight
    • Because if sunlight is present, the C02 produced in respiration will be used in photosynthesis
    • So we must conduct an experiment on respiration in green plants in a dark room
    Question 3.Give examples?
    a) Digestive enzymes

    Answer: The digestive enzymes are

    • Salivary Amylase (Ptyalin)
    • Pepsin
    • Trypsin
    • Lipase
    • Peptidases
    • Sucrase
    • Amylase (Pancreatic juice)
    b) Organisms having heterotrophic nutrition is seen in organisms like?

    Answer: Heterotrophic nutrition is seen in organisms like

    • All animals and human beings
    • Some protozoans Ex: Amoeba
    • Some parasitic plants Ex: Cuscuta
    • Saprophytes Ex: Bread moulds, yeast, mushrooms, etc
    c) Vitamins?

    Answer: Water soluble vitamins: B complex (B1) Thiamine, (B2) Riboflavin, (B3) Niacin, (B6) Pyridoxine, (B12) Cyanocobalamine, Folic acid, Pantothenic acid, Biotin, (C) Ascorbic Acid. Fat soluble: (A) Retinol, (D) Calciferol, (E) Tocoferol, (K) Phylloquinine.

    d) Nutritional deficiency diseases?
    Answer: Eg: Kwashiorkor, Marasmus etc.
    Question 4.Where do plants get each of the raw materials required for photosynthesis?


    Raw materials Sources
    External factors: 1. Carbondioxide Atmosphere
    2. Sunlight Sun
    Internal factors: 3. Water Ground water
    4. Chlorophyll and enzymes Present in leaf
    Question 5.Explain the necessary conditions for autotrophic nutrition and what are its by products?

    Answer: A. Necessary conditions

    • Autotrophic nutrition takes place through the process of photosynthesis
    • Carbon dioxide, water, chlorophyll pigment and sunlight are the necessary conditions required for autotrophic nutrition
    • The rate of photosynthesis depends on availability of sunlight
    • B. By products:
    • Photosynthesis is the main process for autotrophic nutrition
    • Carbohydrates and oxygen are the by products of photosynthesis
    Question 6.With the help of chemical equation explain the process of photosynthesis In detail with the help of a flow chart?

    Answer: Process of photosynthesis

    • The chemical equation representing the process of photosynthesis is
    • Question 7.Name the three end products of photosynthesis?

      Answer: Glucose, oxygen and water are the three end products of photosynthesis

      Question 8.What is the connecting substance between light reaction and dark reaction?

      Answer: The hydrogen of NADPH present in the stroma is the connecting substance between light reaction and dark reaction

      Question 9.Most leaves have the upper surface is more green and shiny than the lower ones. Why?
      (OR) In most of leaves the upper surface will be more green and shiny than the lower surface. Why?


      • The upper surface comprising of the palisade parenchyma
      • The lower surface comprising of the spongy parenchyma
      • Palisade parenchyma contains more number of chloroplasts than the spongy parenchyma
      • Thus the upper surface is more green and shiny than the lower ones
      Question 10.Explain the structure of chloroplast with a neatly labelled sketch?
      (OR) Explain the structure of a chloroplast with the help of a rough diagram.


    • This process takes place in duodenum and small intestine
    Question 15.What is the role of saliva in the digestion of food ?
    (OR) How does saliva digest food ?


    • Saliva is secreted by three pairs of salivary glands present in the mouth
    • Human saliva contains an enzyme called amylase (ptyalin).
    • It converts starch into maltose (a sugar)
    • The food is mixed thoroughly with saliva and becomes wet and slippery
    • Saliva helps in the smooth passage of food in the food pipe
    Question 16.What will happen to protein digestion as the medium of intestine is gradually rendered alkaline ?


    • The food coming from the stomach to intestine is acidic in nature
    • Bile and pancreatic juices render the internal condition of the intestine gradually to a basic or alkaline one
    • Protein digestion continues even if the medium of intestine is gradually changed to alkaline
    • In the alkaline medium pancreatic enzyme trypsin can act on the food and digests the proteins
    Question 17.What is the role of roughages in the alimentary tract?


    • Roughages are the fibres of either carbohydrates or proteins
    • Plenty of roughages in the diet avoid constipation
    • Roughages help in the easy movement of faeces in the large intestine
    • They help in the easy digestion of food and keep the alimentary canal clean and healthy
    Question 18.What is malnutrition? Explain some nutrition deficiency diseases?

    Answer: Malnutrition: Eating of food that does not have one or more than one nutrients in required amount is known as malnutrition. Malnutrition is of three types

    • Calorie malnutrition
    • Protein malnutrition
    • Protein calorie malnutrition
    • Nutrition deficiency diseases:
    • Kwashiorkor disease: This is due to protein deficiency in diet. Symptoms
    • Body parts becomes swollen due to accumulation of water in the intercellular spaces
    • Very poor muscle development
    • Swollen legs
    • Fluffy face
    • difficult to eat
    • diarrhoea
    • Dry skin
    • Marasmus: This is due to deficiency of both protein and calories. Generally this disease occurs when there is an immediate pregnancy or repeated child births
    • Symptoms:
    • Lean and weak
    • Swelling in joints of limbs
    • Less developed muscles
    • Dry skin
    • diarrhoea
    Question 19.How do non-green plants such as fungi and bacteria obtain their nourishment?


    • Bacteria and fungi are non-green plants. So they cannot prepare their own food materials
    • They are saprophytes which feed on dead and decaying plant and animal bodies
    • The fungi and bacteria breakdown the complex organic molecules present in dead and decaying matter by releasing chemical substances into simple substances out¬side the body
    • These simpler substances are then absorbed by fungi and bacteria as their food
    Question 20.If we keep on increasing CO2 concentration in the air, what will be the rate of photosynthesis?


    • If the CO2 concentration in the air increases, the rate of photosynthesis also increases
    • If the CO2 concentration raises above 5% then the rate of photosynthesis reduces
    • At certain CO2 concentration the rate of photosynthesis is constant
    • Here a rise in CO2 levels has no affect on the rate of photosynthesis as the other factors such as light intensity become limited
    Question 21.What happens to plant if the rate of respiration becomes more than the rate of photosynthesis ?


    • Respiration is a catabolic (destructive) process and photosynthesis is an anabolic (constructive) process
    • If the rate of respiration becomes more than the rate of photosynthesis, the amount of food oxidised will be more than the food produced
    • This affects the growth and development of plants and may even results in the death of the plant
    Question 22.Why do you think that carbohydrates are not digested in the stomach?
    (OR) Where are carbohydrates digested in alimentary canal?


    • For the digestion of carbohydrates enzyme ptyalin or amylase are required
    • The gastric juice produced by stomach do not contain the enzyme ptyalin or amylase, it contains only pepsin which digests proteins
    • Hence carbohydrates are not digested in the stomach
    • Carbohydrates are partially digested in the mouth and completely in small intestine
    Question 23.What process do you follow in your laboratory to study the presence of starch in leaves?
    (OR) (Activity - 1) How do you test the presence of starch in leaves ? (OR) Mention the materials required and explain the experiment to prove the presence of starch in leaves. What inference do you draw from this experiment?

    Answer: Aim: To study the presence of starch in leaves. Apparatus: Beaker, test tube, bunsen burner, tripod stand, asbestos gauze, ethanol, leaf, petridish, iodine solution

    • Select a leaf of a potted plant with soft thin leaves
    • Boil the leaf in methylated spirit over a water bath till it becomes pale white due to the removal of chlorophyll.
    • Observe the leaf
      • Arrange the apparatus as shown in the figure
      • Place some water plant hydrilla in a beaker containing pond water, and cover these by a short stemmed funnel
      • Invert a test - tube full of water over the stem of the funnel
      • Ensure that the level of water in the beaker is above the level of stem of the inverted funnel
      • Place the apparatus in the sun for at least 2 or 3 hours
      • After sometime it is observed that gas bubbles come from the hydrilla plant. These bubbles are collected at the end of the test tube pushing the water into the beaker
      • After sufficient gas is collected test - tube is taken out of the beaker carefully by closing it with thumb
      Observation: Test the gas in the test - tube by inserting a glowing incense stick which would burst into flames. This shows the presence of oxygen. Result: This shows that oxygen is produced during photosynthesis. Precautions:
      • Funnel should be smaller than the beaker
      • Necessary care is to be taken while removing the test tube from the stem of the funnel
      Question 25.Collect information from your primary health centre of malnutrition child at various ages and make a table your own and display in the classroom?

      Question 26.If there were no green plants, all life on the earth would come to an end ! Comment?
      (OR) The survival of organisms would become difficult, if there are no green plants on the earth. How do you support?


      • Plants play the most important part in the cycle of nature
      • Without plants there could be no life on earth
      • Plants are the only organisms that can make their own food and all other living beings directly or indirectly depend on plants for their food
      • Moreover plants release oxygen into the atmosphere through photosynthesis
      • Oxygen is essential for the organisms to respire
      • Hence without green plants, all life on the earth would come to an end
      Question 27.Draw a neat labelled diagram of chloroplast found in leaf, and its role in photosynthesis?


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