Photosynthesis ICSE Class-10 Concise Selina Biology Solutions Chapter-6. We Provide Step by Step Answer of Progress Check 1, 2, 3, 4 , MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type Questions and Structured / Applications / Skill Type Questions of Exercise-6 Photosynthesis ICSE Class-10 Concise . Visit official Website CISCE for detail information about ICSE Board Class-10.
Board | ICSE |
Publications | Selina Publishers PVT LTD |
Subject | Concise Biology |
Class | 10th |
writer | HS Vishnoi |
Chapter-6 | Photosynthesis |
Topics | Solutions of MCQs, Very Short ,Descriptive and Structural/Skill Questions and Progress Check 1, 2, 3, 4 |
Edition | 2021-2022 |
Photosynthesis ICSE Class-10 Concise Selina Biology Solutions Chapter-6
-: Select Topics :-
A. MULTIPLE CHOICE TYPE
B. VERY SHORT ANSWER TYPE
C. SHORT ANSWER TYPE
D. DESCRIPTIVE TYPE
E. STRUCTURED/APPLICATION/SKILL TYPE
A. MULTIPLE CHOICE TYPE Photosynthesis ICSE Class-10 Concise Selina Biology
Page 78
Question 1:
The production of starch, and not glucose, is often used as a measure of photosynthesis in leaves because
(a) starch is immediate product of photosynthesis
(b) glucose formed in photosynthesis soon gets converted into starch
(c) starch is soluble in water
(d) sugar cannot be used
Answer 1
(b) glucose formed in photosynthesis soon gets converted into starch
Question 2
The number of water molecules required in the chemical reactions to produce one molecule of glucose during photosynthesis is
(a) six
(b) twelve
(c) eighteen
(d) twenty-four
Answer 2
(b) twelve
Question 3
The rate of photosynthesis is not affected by
(a) light intensity
(b) humidity
(c) temperature
(d) CO2 concentration
Answer 3
(b) humidity
Question 4
Chlorophyll in a leaf is required for
(a) breaking down water into hydrogen and oxygen
(b) emitting green light
(c) trapping light energy
(d) storing starch in the leaves
Answer 4
(c) trapping light energy
Question 5
If the rate of respiration becomes more than the rate of photosynthesis, plants will:
(a) continue to live, but will not be able to store food
(b) be killed instantly
(c) grow more vigorously because more energy will be available
(d) stop growing and die gradually of starvation
Answer 5
(a) continue to live, but will not be able to store food
Question 6
Which one chemical reaction occurs during photosynthesis?
(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
Answer 6
(a) Carbon dioxide is reduced and water is oxidised
Question 7
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
Answer 7
(c) activate chlorophyll
Question 8
A plant is kept in a dark cupboard for 48 hours before conducting any experiment on photosynthesis in order to
(a) remove chlorophyll from leaves
(b) remove starch from the leaves
(c) ensure that no photosynthesis occurred
(d) ensure that the leaves are free from starch
Answer 8
(d) ensure that the leaves are free from starch
Question 9
During photosynthesis, the oxygen in glucose comes from
(a) CO2
(b) water
(c) both CO2and water
(d) oxygen via air
Answer 9
(a) CO2
B. VERY SHORT ANSWER TYPE Photosynthesis ICSE Class-10 Concise Selina Biology
Page 78-79
Question 1:
Name the following:
(a) The category of organisms that prepare their own food from basic raw materials.
(b) The kind of plastids found in the mesophyll cells of the leaf.
(c) The compound which stores energy in the cells.
(d) The first form of food substance produced during photosynthesis.
(e) The organisms that can be called “natural purifiers” of the air.
(e) The source of carbon dioxide for aquatic plants.
(f) The part of chloroplast where the dark reaction of photosynthesis takes place.
Answer 1
(a) Producers / Autotrophs
(b) Chloroplasts
(c) ATP (Adenosine triphosphate)
(d) Glucose
(e) Carbon dioxide dissolved in water
(f) Stroma
Question 2:
Given below are groups of terms. In each group, the first pair indicates the relationship between the two terms. Complete the second pair accordingly.
(a) Chlorophyll : Magnesium : : Haemoglobin : ………….
(b) Light reaction : Granum : : Dark reaction : ……………
(c) Producers : Autotrophs : : Consumers : …………….
(d) Respiration : Carbon dioxide : : Photosynthesis : ………….
(e) Water and minerals : Xylem : : Prepared food : …………………
Answer :
(a) Chlorophyll : Magnesium : : Haemoglobin : oxygen
(b) Light reaction : Granum : : Dark reaction : Calvin
(c) Producers : Autotrophs : : Consumers : hetrotrophs
(d) Respiration : Carbon dioxide : : Photosynthesis : oxygen
(e) Water and minerals : Xylem : : Prepared food : pholem
C. SHORT ANSWER TYPE for ICSE Class-10 Chapter 6 Photosynthesis
Page 79
Question 1
Identify the false statements and rewrite them correctly by changing the first or last word only.
(a) Dark reaction of photosynthesis occurs during night time.
(b) Photosynthesis requires enzymes.
(c) Green plants are consumers.
(d) Photosynthesis results in loss of dry weight of the plants.
(e) Photosynthesis stops at a temperature of about 35oC.
(f) Photosynthesis occurs only in cells containing chloroplasts.
(g) Green plants perform photosynthesis.
(h) Algae are autotrophs.
Answer 1
(a) False
Correct Statement: Dark reaction of photosynthesis is independent of light and occurs simultaneously with light reaction.
(b) True
(c) False
Correct Statement: Green plants are producers.
(d) False
Correct Statement: Respiration results in loss of dry weight of the plants.
(e) False
Correct Statement: Photosynthesis stops at a temperature of above 40oC.
(f) True
(g) True
(h) True
Question 2
Fill in the blanks with the appropriate answer from the choices given in the brackets.
(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 …………. (CaCl2, iodine solution, Benedict solution)
(c) Stroma is ground substance in ……………. (cytoplasm, chloroplast, ribosomes)
(d) The dark reaction of photosynthesis is known as ………….. (Hill reaction, cyclic phosphorylation, Calvin cycle)
(e) In the flowering plants, food is transported in the form of ……………… (sucrose, glucose, starch)
Answer 2
(a) The site of light reaction in the cells of a leaf grana
(b) The chemical substance used to test the presence of starch in the cell of a leaf is iodine solution
(c) Stroma is ground substance in chloroplast.
(d) The dark reaction of photosynthesis is known as Calvin cycle
(e) In the flowering plants, food is transported in the form of sucrose
Question 3
Are the following statements true or false? Give reason in support of your answer.
(a) The rate of photosynthesis continues to rise as long as the intensity of light rises.
(b) The outside atmospheric temperature has no effect on the rate of photosynthesis.
(c) If you immerse a leaf intact on the plant in ice cold water, it will continue to photosynthesise in bright sunshine.
(d) Destarching of the leaves of a potted plant can occur only at night.
(e) If a plant is kept in bright light all the 24 hours for a few days, the dark reaction (biosynthetic phase) will fail to occur.
(f) Photosynthesis is considered as a process supporting all life on earth.
Answer 3
(a) False
Photosynthesis increases with the light intensity up to a certain limit only and then it gets stabilized.
(b) False
The atmospheric temperature is an important external factor affecting photosynthesis. The rate of photosynthesis increases up to the temperature 35oC after which the rate falls and the photosynthesis stops after 40oC.
(c) False
Ice 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.
(d) False
For destarching, the potted plant can kept in a dark room for 24-48 hours.
There is no start point or end point in the carbon cycle, the carbon is constantly circulated between the atmosphere and the living organisms.
(e) False
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 the dark reaction is independent of light and it occurs simultaneously with the light dependent reaction.
(f) True
Question 4
Given below are five terms. Rewrite the terms in the correct order so as to be in logical sequence with regard to photosynthesis: (i) water molecules, (ii) oxygen, (iii) grana, (iv) hydrogen and hydroxyl ions, (v) photons.
Answer 4
Photons, grana, water molecules, hydrogen and hydroxyl ions, oxygen
Question 5
State any four differences between photosynthesis and respiration.
Answer 5
Photosynthesis | Respiration |
Carbon dioxide is used up and oxygen is released. | Oxygen is used up and carbon dioxide is released. |
Photosynthesis occurs in plants and some bacteria. | Respiration occurs in all living organisms. |
Photosynthesis results in gain of dry weight of the plants. | Respiration results in loss of dry weight of the plants. |
Glucose is produced which is utilized by the plants. | Glucose is broken down to obtain energy. |
The raw materials for the photosynthesis are water, carbon dioxide and sunlight. | The raw material for respiration is glucose. |
Question 6
Complete the following food chains by writing the names of appropriate organisms in the blanks:
(i) Grass → ………… Snake → ……………
(ii) ……….. → Mouse …………… → Peacock
Answer 6
Complete the following food chains by writing the names of appropriate organisms in the blanks:
(i) Grass → Rabbit. → Snake → Hawk
(ii) Grass/Corn → Mouse → Snake → Peacock
Question 7
How do non-green plants such as fungi and bacteria obtain their nourishment?
Answer 7
Non-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.
Question 8
All life owes its existence to chlorophyll. Give reason.
Answer 8
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) from the atmosphere, and water (H2O) 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.
Question 9
Complete the following by filling the blanks 1 to 5 with appropriate words/ terms/ phrases:
To test the leaf for starch, the leaf is boiled in water to …………… (1). It is next boiled in methylated spirit to ……………(2). The leaf is placed in warm water to soften it. It is then placed in a dish and ………….(3) solution in added. The region, which contains starch, turns ……………. (4) and the region, which dose not contain starch, turns ………………(5)
Answer 9
To test the leaf for starch, the leaf is boiled in water to kill the cells. It is next boiled in methylated spirit to remove chlorophyll. The leaf is placed in warm water to soften it. It is then placed in a dish and iodine solution in added. The region, which contains starch, turns blue-black and the region, which does not contain starch, turns brown.
Question 10
“Oxygen is a waste product of photosynthesis.” Comment.
Answer 10
Oxygen 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.
D. STRUCTURED / APPLICATION / SKILL TYPE for ICSE Class-10 Chapter 6 Photosynthesis Concise Selina Biology
Page 79-80
Question 1
Define the following Terms :
(a) Photosynthesis
(b) Thylakoids
(c) Chloroplast
(d) Photolysis of water
(e) Polymerisation
Answer 1
(a) Photosynthesis : photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.
(b) Thylakoids : Thylakoids are membrane-bound compartments inside chloroplasts and cyanobacteria. They are the site of the light-dependent reactions of photosynthesis.
(c) Chloroplast : Chloroplasts are organelles that conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in plant and algal cells.
(d) Photolysis of water : Photolysis is the splitting of water molecules in the presence of light into proton, electron and oxygen.
(e) Polymerisation : Any process in which relatively small molecules, called monomers, combine chemically to produce a very large chainlike or network molecule, called a polymer. The monomer molecules may be all alike, or they may represent two, three, or more different compounds.
Question 2
Photosynthesis in green plants is directly and indirectly dependent on so many plant structures. Explain briefly the role of the following structures in this process.
(a) Guard cells
(b) Cuticle
(c) Chlorophyll
(d) Stomata
(e) Xylem tissue in the leaf veins
(f) Phloem tissue in the leaf veins
Answer 2
(a) Guard cells: They regulate the opening and closing of stomata and thus regulate the entry of carbon dioxide through the stomata.
(b) Cuticle: Cuticle is transparent and water proof due to which light can penetrate this later easily.
(c) Chlorophyll : Chlorophyll is a pigment present in all green plants and a few other organisms. It is required for photosynthesis, which is the process by which light energy is converted into chemical energy
(d) Stomata: The main function of stoma is to let in carbon dioxide from the atmosphere for photosynthesis. Also most of the oxygen produced during photosynthesis diffuses out into the atmosphere through the stomata.
(e) Xylem Tissue in the Leaf Veins: Water is essential for photosynthesis to occur. Water is taken up by the roots from the soil, sent up through the stem and finally brought to the leaves (site of photosynthesis) through the xylem tissue. The water is then distributed in the mesophyll tissue.
(f) Phloem Tissue in the Leaf Veins: The prepared food is transported from leaves to all parts of the plant by the phloem tissue. The glucose is converted into insoluble starch and later into soluble sugar i.e. sucrose, which is transported in solution through the phloem in the veins of the leaf and down through the phloem of the stem.
Question 3
Give reasons/explain
(a) It is necessary to place a plant in the dark before starting an experiment on photosynthesis.
(b) It is not possible to demonstrate respiration in a green plant kept in sunlight.
(c) Most leaves have the upper surface more green and shiny than the lower surface.
(d) During the starch test the leaf is-
(1) boiled in water.
(2) boiled in methylated spirit.
Answer :
(a) It is necessary to place the plant in a dark room for the experiment of photosynthesis because as we all know that photosynthesis take place in the presence of Sunlight so if you want to test the process of photosynthesis for any experiment related to photosynthesis then it is necessary to place the plant in a dark room where the sunlight cannot reach
(b) Yes it is not possible to to demonstrate respiration in green plants kept in sunlight because if they are in sunlight then they will do their all process in the presence of Sunlight and we cannot find any difference between them if they are in sunlight
(c) More sleep have their upper surface more green than the lower surface because they are much closer to the rays of Sun light it and the lower surface are not as much closer as to the upper surface that is why the upper surface is more Shiny and Greeny than the lower surface
(d) If we want to test the starch in the leaf then we should boil it in a water because if we boil it then they will lose all their colour and green pigment and turn their colour into black and in this way we can easily find out or perform the reaction of the experiment of starch
Question 4:
Distinguish between the following pairs on the basis of words indicated in the brackets ().
(a) Light reaction and Dark reaction (end products)
(b) Producers and Consumers (organisms)
(c) Grass and Grasshopper (mode of nutrition)
(d) Stoma and Stroma (structure)
Answer
(a) light rxn-- thylakoids – ATP + NaDph
dark rxn-- stroma– ATP only
(b)
producers- phytoplankton
consumer- zooplankton
(c)
grass-autotrophic
grasshopper-heterotrophic
(d)
Stoma – outside a leaf
stroma – inside a leaf
Question 5
How would you demonstrate that green plants release oxygen when exposed to light ?
Answer
(a) Place some water plants (Elodea or Hydrilla) in a beaker containing pond water and cover them by a short-stemmed funnel.
(b) 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 the stem of the inverted funnel).
(c) Place the apparatus in the sun for a few hours. Bubbles of the gas will collect in the test-tube.
(d) Test the gas in the test-tube. A glowing splinter bursts into a flame which shows the presence of oxygen.
Question 6
Describe the main chemical changes which occur during photosynthesis in.
(i) Light reaction
(ii) Dark reaction
Answer
(i) Light reaction:
(ii) Dark reaction.
Two main steps:
(a) Activation of chlorophyll : When the plant is exposed to sunlight, light energy is absorbed in the form of photons by the chlorophyll which then becomes active.
(b) Splitting of water : The energy absorbed is used up to split the water molecule into hydrogen, hydrogen ions and oxygen. This is photolysis of water.
Photolysis of water
The above equation is explained as :
1. Hydrogen ion obtained is picked up by NADP to form NADPH.
2. Oxygen is released as molecular oxygen.
3. The electrons are used to convert ADP to ATP using inorganic phosphate group.
Both light and dark reaction occur simultaneously. The light reaction is dependent on the presence of light energy, but the dark reaction is independent of light. These are the two main phases of photosynthesis in green plants.
E. STRUCTURED/APPLICATION/SKILL TYPE
Photosynthesis ICSE Class-10 Concise Selina Biology
Page 80-81
Question 1
Given below is a schematic diagram to illustrate some aspects of photosynthesis.
(a) Fill up the gaps, in blank spaces (1-4), by writing the names of the correct items.
(b) What phenomenon do the thick arrows A and B indicate?
Answer 1
(a)
1 – Sunlight
2 – Oxygen
3 – Glucose
4 – Xylem
(b) A – Transpiration
B – Translocation
Question 2
Given below is the representation of a certain phenomenon in nature. With four organisms 1-4.
(a) Name the phenomenon represented.
(b) Name any one organism that could be shown at No .5
(c) Name the biological process which was the starting point of the whole chain.
(d) Name one natural element which all the organisms 2-4 and even 5 are getting from No. 1 for their survival.
Answer 2
(a) Food chain
(b) Hawk, eagle
(c) Photosynthesis
(d) Carbon
Question 3
A potted with variegated leave was taken in order to prove a facrtor necessary for the photosynthesis. The potted plant was kept in the dark of 24 hours and the n placed in bright sunlight for a few hours. Observe the diafram and answer the question :
(a) What aspect of photosynthesis is being tested in the above diagram?
(b) Represent the process of photosynthesis in the form of a balanced equation.
(c) Why was the plant kept in the dark before beginning the experiment?
(d) What will be the result of the starch test performed on Leaf ‘A’ shown in the diagram ? Give an example of a plant with variegated leaves
(e) Draw a neat labelled diagram of a chloroplast.
Answer 3
(a) To show that chlorophyll is necessary for photosynthesis.
(b)
(c) To destarch the leaves.
(d) It will not turn blue. Example of plants with variegated leaves is Oxalis species.
(e) Chloroplast:
Question 4
Given belong is the diagram of an experimental set-up:
(a) What is the objective of this experiment?
(b) Will it work satisfactorily? Given reason.
(c) What alteration (s) will you make in it for obtaining expected result?
(d) Would you take any step before starting the experiment? Describe this step and explain its necessity.
Answer 4
(a) To demonstrate the importance of carbon dioxide in photosynthesis
(b) No, the experiment will not work satisfactorily, as the beaker contains lime water and not potassium hydroxide to absorb CO2.
(c) Place potassium hydroxide in the beaker instead of lime water
(d) Before starting the experiment, it is necessary to destarch the leaves of the plant by keeping the plant in complete darkness for 48 hours. This is because if the plant is not destarched, then the experiment will give false results because starch stored previously may be detected in the leaf placed in the beaker even if no starch is produced during the experiment.
Question 5
Draw a neat diagram of the stomatal apparatus found in the epidermis of leaves and label the Stoma, Guard cells, Chloroplast, Epidermal cells, Cell wall and Nucleus.
Answer 5
Question 6
The diagram below shows two test-tubes A and B. Test-tube A contains a green water plant. Test-tube B contains both a green water plant and a snail. Both test-tubes are kept in sunlight. Answer the questions that follow:
(a) Name the physiological process that releases the bubbles of oxygen.
(b) Explain the physiological process as mentioned above in (a).
(c) What is the purpose of keeping a snail in test-tube B?
(d) Why does test-tube B have more bubbles of oxygen?
(e) Give an example of a water plant that can be used in the above experiment.
(f) Write the overall chemical equation for the above process.
Answer 6
(a) Photosynthesis releases bubbles of oxygen.
(b) Photosynthesis is a physiological process by which plant cells containing chlorophyll produce food in the form of carbohydrates by using carbon dioxide, water and light energy. Oxygen is released as a by-product.
(c) Carbon dioxide released by the snail during respiration is used by the plant for photosynthesis. This increases the rate of photosynthesis in the plant placed in test tube B. This also suggests that both respiration and photosynthesis are complementary processes to maintain the concentration of oxygen and carbon dioxide in the atmosphere.
(d) A plant and a snail are kept in test tube B. The plant in test tube B has more concentration of CO2 available because the snail releases CO2 during respiration. This increases the rate of photosynthesis in the plant placed in test tube B which leads to the release of more amount of oxygen.
(e) Hydrilla
(f) Chemical equation for photosynthesis:
–: End of Photosynthesis ICSE Class-10 :–
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