Selina Concise Class 10 Biology Solution Chapter No. 6- ‘Photosynthesis’ For ICSE Board Students.
Progress Check
1.)
(i) Answer: No
(ii) Answer:- Yes
(iii) Answer:-Yes
(iv) Answer:- Yes
(v) Answer:- Yes
(vi) Answer:- No
(vii) Answer:- No
Progress check
1) Solution:
Answer:-
6CO2 + 6H2O → C6H12O6 + 6O2 + 6H2O
Carbon water glucose oxygen water
Dioxide
2) Solution:
Answer:- the single substance in above equation is repeated in raw material also reproduced as an end product is Water.
3) Solution
Answer:- H2O is that the source of oxygen which is released during photosynthesis.
4) Solution:
Answer:- During the photolysis, the given bellow changes are occurred
- Water is split
- Light is split.
- Energy is stored.
- Energy is released.
5) Solution:
Answer:- Because these reactions are independent of Sun light energy, therefore this phase is known as dark reaction.
6) Solution:
Answer:- Polymerisation mean forming of long chains or polymer (complex compound) from monomers that’s simple molecules.
7) Solution:
Answer:- Because, this dark reaction doesn’t require sunlight, So it’s better to call the dark phase of photosynthesis as “light-independent phase.”
Progress Check
1) Solution:
i) Large surface area of the leaf.
Answer:–Large Surface area of the leaf the fall on the leaves allows more sunlight and thus maximum absorptionOf light which favours increase rate of photosynthesis.
ii) Thinness of the leaf.
Answer:- Thickness of the leaf, there would be rapid transport as the distance between the cells would be less thus facilitating increased photosynthesis rate.
iii) More numerous stomata.
Answer:- presence of more numerous stomata would allow rapid exchange of gases .i.e.oxygen is given out and carbon dioxide is taken in, thus rate of photosynthesis increases.
2) Solution:
Answer:- Carbohydrate, oxygen and water are three end products of photosynthesis.
3) Solution:
Answer:- No, if we keep on increasing carbon dioxide concentration in the air, the rate of photosynthesis will not keepOn increasing direct proportion., Because carbon dioxide increases that rate of photosynthesis increases but only if not limited by other factors like light and temperature. This increase is observed up to 1% of carbon dioxide concentration.
Progress Check
1) Solution:
Answer:- Because, not a particular factor (carbon dioxide, light, water) is important for the photosynthesis Reaction. So, it is important detach the leaves of a plant before performing an experiment on photosynthesis.
2) Solution:
Answer:- Because, in the presence of starch iodine gets trapped within starch carries to form a deep violet charge transfer starch -I2 complex. When all the starch is converted into simpler compounds, no complex will form, therefore no violet colour appear. So, decolourisation of violet colour is the observation with tell us that all starch has converted into simpler products.
3) Solution:
Answer:- Potassium Hydroxide is used to remove CO2 from inside a flask in certain experiment on photosynthesis.
4) Solution:
Answer:- Because plants can make their food by photosynthesis, So all food chains start with a plant.
5) Solution:
Answer:-The honey bee produces honey. In terms of the food chain, the honey bee are not a producers, they are consumers.
Exercise Solution
A. MULTIPLE CHOICE TYPE.
1) The production of starch , and not glucose, is often used as a measure of Photosynthesis in leaves because.
Answer:- b) Glucose formed in photosynthesis soon gets converted into starch.
Explanation: Chloroplast is small microscopic organelle contain leaves then utilize the glucose. So it presence can’t be detected but starch is stored in plants and it can be easily detected.
2) The number of water molecules required in the chemical reaction to produce one molecules of glucose during Photosynthesis is
Answer:- b) Twelve
There is 24 molecules of hydrogen and it spilled into 12 molecule of hydrogen in Sugar and 12 molecule of water in the photosynthesis process.
3) The rate of Photosynthesis is Not affected by
Answer:- b) humidity
Explanation: Humidity is almost negligible role in the photosynthesis.
4) Chlorophyll in a leaf is required for.
Answer:- c) trapping light energy.
Explanation: Chlorophyll absorbs light energy convert into chemical energy.
5) If the rate of respiration become more than the rate of Photosynthesis, plants will
Answer:- a) Continue to live, but will not be able to store food.
Explanation: Because the higher rate of respiration , leading to more rate of oxygen consumption.
6) Which one chemical reaction occurs during Photosynthesis?
Answer:-a) Carbon dioxide is reduced and Oxygen is Oxidized.
Explanation: During photosynthesis, carbon dioxide reduced to carbohydrates and water is oxidized into oxygen molecules.
7) The specific function of light energy in the process of Photosynthesis is to.
Answer:- c) Activate chlorophyll.
Explanation: Photons of light excited chlorophyll, which emit high energy electron that used in formation of ATP.
8) Plant is kept in a dark cupboard for about 48 hours before conducting any experiment on Photosynthesis in order to
Answer:- d) Ensure that the leaves are free from starch.
Explanation: Plant is kept in dark cupboard for 48 hours then the photosynthesis process will stop due to this, stored starch used up to making leaf starch less.
9) During Photosynthesis, the oxygen in glucose comes from.
Answer:- a) CO2
Explanation: When plants makes the glucose molecule, it gets the carbon and oxygen atoms from carbon dioxide by the air through stomatal opening.
B. VERY SHORT ANSWER TYPE
1) Solution:
a)
Answer:- Producer or autotrophs are prepare their own food from basic raw material.
b)
Answer:- Chloroplast plastid is found in the mesophyll cells of the leaf.
c)
Answer:- Adenosine Triphosphate(ATP) stores energy in the cells.
d)
Answer:- Glucose is the first form substance produced during Photosynthesis.
e)
Answer:- The source of CO2 for aquatic Plants is CO2 dissolved in water.
f)
Answer:- Stroma is the part of chloroplasts where dark reaction of photosynthesis take place.
2)
a) Chlorophyll: Magnesium ::Hemoglobin : _______________
Answer:-
Chlorophyll:Magnesium ::Hemoglobin:Iron.
b) Light reaction :Granum::Dark reaction:______________________
Answer:-
Light reaction:Granum::Dark reaction:Stroma.
c) producers :Autotrophs ::
Consumers:___________________
Answer:-
producer: Autotrophs :: consumers: Heterotrophs
d) Respiration: Carbon dioxide::Prepared food:_______________
Answer:-
Respiration: Carbon dioxide ::prepared food: Oxygen.
e) Water and minerals: xylem Prepared food:_________
Answer:-
Water and minerals: xylem::prepared Food: phloem.
C. SHORT ANSWER TYPE
1) Solution:
a)
Answer:-False
Dark reaction of photosynthesis occurs during the day.
b)
Answer:- True
c)
Answer:–False
The Green plants are Producer.
d)
Answer:- False
Respiration result in loss of dry weight of the plants.
e)
Answer:- False
Photosynthesis stops at a temperature of about 40°C.
f)
Answer:–True
g)
Answer:- True
h)
Answer:–True
2) Solution:
a) Answer:- The site of light reaction in the cells of a leaf is grana.
b) Answer:- The chemical substance used to test the presence of starch in the cell of a leaf is iodine solution.
c) Answer:- Stroma is the groundSubstance in Chloroplast.
d) Answer:- The dark reaction of photosynthesis is also known as Calvin cycle.
e) Answer:-In the flowering plants, food is Transported in the form of Sucrose.
3) Solution:
a)
Answer:- False
The rate of photosynthesis increases with light intensity.
b)
Answer:– False
Rate of photosynthesis is increases with the rise in temperature. The increase occurs upto the optimum temperature 35°c after it falls and stops above 40°c.
c)
Answer:- False
Ice cold water will hamper the process of photosynthesis within the immersed leaf, whether or not there’s sufficient sunshine.
d)
Answer:- False
Destarching of the leaves of a potted plant can occur at day too.
e)
Answer:- False
If a plant kept in bright light all the 24 hours for some days, the dark reaction will continue because dark reaction independent of sunshine and thus, it’ll occurs simultaneously with might dependent reaction.
f)
Answer:- True.
4) Solution:
Answer:-
Correct order:-
Photons→ grana→ water molecule→ oxygen→ hydrogen and hydroxyl ions
5) Solution:
Answer:-
Photosynthesis |
Respiration |
These is the process of formation of food for growth of plant
|
These is the process of respiration occurs in all living things |
It is dependent over the light | It is independent over the light
|
In These process release of carbon dioxide release and used also.
|
In these Process carbon dioxide is released and oxygen is used. |
These process has two stages –
Dark reaction and light reaction |
These process has two stages –exhalation and inhalation |
6)
i) Grass →________ →snake →_____
ii) _____ →Mouse ______ → Peacock
Answer:-
i) Grass-→ Rat→ snake→ Hawk.
ii) Corn→Mouse→Snake→ peacock.
7) Solution:
Answer:-
Non- green plants such as fungi and bacteria took their nourishment from Dead and decaying organic matter in their environment. This matter comes from dead animals and plants which in their own turn were depends upon photosynthesis.
8) Solution:
Answer:-
Cell organelles called chloroplasts. Chloroplasts are minute oval bodies bounded by a double- membrane, and their interior contains closely packed flattened sacs arranged in piles living in an exceedingly colourless ground substance called the stroma, there is also 40-50 chloroplasts in an exceedingly cell. The pigment chlorophyll is contained within the walls of thylakoids. It’s a highly complex substance composed of carbon, hydrogen, oxygen, nitrogen and magnesium chloroplasts are mainly contained within the mesophyll cells located between the upper epidermis and lower epidermis of leaves. There are alis found within the guard cells to stomata and within the outer layers of green stems.
9) Solution:
Answer:-
To test the leaf for starch, the leaf is boiled in water To kill the cells . ItIs next boiled in methylated spirit to removechlorophyll. The leaf is placed in warm water to soften it. It is then placed in a dish and iodine solution is added. The region which contains starch turns blue–black colour and the region, which does not contain starch turns brown colour.
10) Solution:
Answer:-
Oxygen support all life on the planet. No living being can Live without oxygen. Photosynthesis is that the only organic process which releases oxygen into the atmosphere. Photo-respiration Is some of the oxygen utilized in respiration in leaf cell but the main portion of of the it not required and it diffuses out into the atmosphere through the stomata. All organisms required it for his or her existence including plants. And thus oxygen isn’t waste of photosynthesis.
D. DESCRIPTIVE TYPE
1) Solution:
a) Photosynthesis
Answer:- Photosynthesis is the process in which the transformation of light Energy into chemical energy by green parts of the plants.
b) Thylakoids
Answer:- Thylakoids is a membrane-bound compartment inside chloroplast and Cyanobacteria.
c) Chloroplast
Answer:- Chloroplast are organelles that have a double membrane and stacks of disc-like shapes containing chlorophyll.
d) Photolysis of water
Answer:- The process of decomposition of water into hydrogen and oxygen by light energy observed by chlorophyll is called Photolysis. The oxygen produced by the photolysis of water is released into air as a by product.
e) polymerisation
Answer:- polymerisation is the process in which small molecules called as monomer that combine chemically to produce a very large chain like molecules, called as polymer.
2.) Solution:
Answer:-
a) Guard cells:-
In the guard cells, opening and shutting of stomata within the leaves by the method of photosynthesis. The indirectly control the movement of carbonic acid gas through the stomata.
b) Cuticle:- The cuticle allows light to penetrate very easily, waterproof and transparent.
c) Chlorophyll:-
Chlorophyll is green pigment found in plants. It’s contained in microscopic cell organelles called chloroplasts.
d) Stomata:-
The stomata is regulated by the movement of dioxide from the atmosphere into the cells.
e) Xylem tissues within the leaf veins :-
The process of photosynthesis water is extremely essential, the xylem tissues controls the movement of water preoccupied by root of the plant and direct it up to the leaves.
f) Phloem tissues within the leaf veins:-
The food prepared by photosynthesis is transported the phloem tissues from the leaves to the opposite parts of the plant.
3) Solution:
a) Answer:-
The plant kept within the dark room before starting the experiment, it’s unable to perform photosynthesis and derives it’s energy solely from the left over starch within the plants.
b) Answer:- It is impossible to demonstrate respiration in a very green plants kept in sunlight, because during the day time, plants are undergoing Photosynthesis. As we all know oxygen is consumed during respiration in plants. So it can’t be demonstrated at the day time, as plants do respiration at midnight.
c) Answer:-
Because great amount of chloroplasts is present within the upper layers of the leaf which helps in photosynthesis. The side of Leaves thick cuticle is roofed So it makes side of leaves more shiny than lower surface.
d) Answer:-
1) Boiled in water:-
The alcohol boil the leaf. Check the starch to eradicate chlorophyll, the green pigment present in leaves. During the starch test, brown to blue colour changes of leaf and when put a iodine on the leaf and reacts iodine.
2) Boiled in methylated spirit:-
Boiled in methylated spirit to remove all the starch present in the leaves of the plant . The leaf kept in boiling water to kill the cell. Boiled in methylated spirit to remove chlorophyll.
4) Solution:
a)
Answer:-
Lightreaction | Darkreaction |
Light reaction is the Trapping of energy of sunlight. | Dark reaction consist of the process of transfer of hydrogen molecules from NADPH. |
Light energy is used for the splitting of molecules of water into hydrogen, oxygen and hence it forms the ATP. | Dark reaction is used to form the C6H12O6 by using ATP, Carbon dioxide, and hydrogen. |
b)
Answer:-
Producers | Consumers |
Producers are those which make their own food. | Consumers used the food which is made by producers. |
These are known As Autotrophs | These are known As Heterotrophs |
These contains all green plants. | These contains all the animals which eats plants or another animals. |
c)
Answer:-
Grass | Grasshopper |
Grass is a type of plant. | Grasshopper is an animal. |
These is producer | It is a consumer |
It is Autotrophs | It is Heterotrophs |
It produces it’s Own food By photosynthesis
Hence the mode of Nutrition is Self nutrition. |
It does not made its own food it is dependent over the Producer for food. Such as grass. |
5) Solution:
Answer:-
i) A beaker containing pond water in some water plants (Hydrilla or Elodea) and short -steamed funnel by covered them.
ii) The stem of funnel invert a test-tube stuffed with water (The level of water within the beaker is above the amount of the stem of the inverted funnel).
iii) The few hours place the apparatus within the sun. The test-tube collect bubbles of the gas.
6) Solution:
Answer:-
i) Light reaction:-
The two main steps occurs in light reaction.
Step 1:- Chlorophyll of activation.
The absorbing photons activated becomes the exposure to light energy the chlorophyll.
Step-2 :- Splitting of water.
The two components (Hydrogen and oxygen) the absorbed energy is used in splitting the water molecule and electron releasing.
Step-3 :- ADP(Adenosid diphosphate) is added with phosphate group P1 (inorganic phosphate) , the electrons are used in converting ADP into energy rich compound ATP (Adenosine Triphosphate).
ii) Dark reaction:-
Do not require light energy this phase of the reaction and simultaneously occurs with light energy.
E. STRUCTURE /APPLICATION /SKILL TYPE
1) Given below is a schematic diagram to illustrate some aspects of Photosynthesis ..
a)
Answer:-
1]Sunlight
2]Oxygen
3]Glucose
4]Water.
b)
Answer:- A indicating Transpiration
Phenomenon and B indicating Ascent Of Sap phenomenon.
2)
a)
Answer:- Food chain is phenomenon represented.
b)
Answer:- Hawk could be shown at No.5.
c)
Answer:- the biological process which was at the starting point of the whole chain is photosynthesis.
d)
Answer:- the element which all organisms 2-4 and even 5 are getting from No. 1 for their survival is oxygen.
3)
a)
Answer:- In the above diagram, aspect of photosynthesis is being tested.
b)
Answer:- Because, the process of photosynthesis does not occurs in dark and stored starch used up. So, the plant placed in the dark before beginning the experiment.
c)
Answer:- these is the balanced chemical equation of photosynthesis –
6CO2+6H2O→C6H12O6+6O2+6H2O
Carbon water glucose oxygen water
Dioxide
d)
Answer:- when the leaves kept in dark, and tested the starch with iodine, then generally produce blue-black colour but in this experiment it will not turn blue-black colour. In the dark, plant can’t able to prepare its food. And Therefore, leaf A not gives accurate result with starch test .
e)
4)
a) Answer:- To describe the important ofCarbon dioxide in photosynthesis , this is objective of this experiment.
b) Answer:- This experiment will not satisfactorily, because of presence of lime water in this experiment and lime water does not absorb Carbon dioxide and carbon dioxide is important in photosynthesis process.
c) Answer:- For obtaining expected result, insert Potassium hydroxide in it by replacing the lime water.
d) Answer:– Yes, we take some steps before starting the experiment. Firstly, we take a plant and placed 24 -48 hours in the dark and during this period, leaves will be distarch and also Starch will be removed from the leaves as well as it stored in storage organs. And therefore, the leaves not show the presence of starch .
5)
6) Solution:
a) Answer:- The name of the physiological process that releases the bubbles of oxygen is photosynthesis.
b) Answer:- Photosynthesis is the physiological process as mentioned above in (a) . And in this process, all green plants which synthesis food from carbon dioxide as well as water in the presence of chlorophyll and light energy.
c) Answer:- Snail releases carbon dioxide during respiration and due to this rate of photosynthesis increases by increasing the concentration of carbon dioxide. This is purpose of keeping a snail in test -tube ‘B’.
d) Answer:- Because in test-tube ‘B’ Snail is kept and so concentration of carbon dioxide is more which leading to release more amount of oxygen.
e) Answer:- Hydrilla or Elodea is example of a water plant that can be used in the above experiment.