Photosynthesis is a process through which green plants can make their own food. Conditions needed for photosynthesis include the presence of carbon dioxide, water, chlorophyll and sunlight. The process through which reserved starch are removed from plant by keeping the plant in a darkroom is called destarching.

Quantasomes are particles found in the chloroplast thylakoid membrane where photosynthesis occurs. They are considered as photosynthetic units which is equivalent to a packet containing 250-300 chlorophyll molecules, carotenoids, quinone compounds, phospholipids, etc.

Stroma is a protein colloidal complex that fits the interior of the chloroplast are regarded as the site of light reaction of photosynthesis units are located there. Granum are green coloured structures embedded in the stroma, each consists of many disc-shaped membranous sac called thylakoids.

Match the following: Column I Column II i) Autotrophs a) Is the place for light reaction of photosynthesis ii) Photolysis b) Is the place for dark reaction of photosynthesis iii) Bacteria and fungi c) Light reaction iv) Stomata closed d) During night v) By-products of photosynthesis e) Green plants vi) The grana f) Oxygen vii) The stroma g) Decomposers.

i)-(e) Plants are known as autotrophs because they are able to prepare their own food. ii)- (c) Photolysis of water is a first step in light reaction process through which water is broken down into oxygen, hydrogen ion (proton) and electrons. iii)-(g) Bacteria and fungi can decompose rotten material and increase soil fertility. iv)-(d) Photosynthesis cannot take place at night as photolysis of water would not take place. Stomata help in the exchange of gases like oxygen and carbon dioxide. It remains closed during night. v)-(f) By-products of photosynthesis are glucose and oxygen. vi)-(a) In grana, light reactions of photosynthesis takes place. Thylakoids are arranged in stacks like the piles of coins called grana (singular; granum). vii)-(b) In stroma, dark reaction of photosynthesis takes place. The stroma of the chloroplast contains enzymes required for the synthesis of carbohydrates and proteins. Column I Column II i) Autotrophs e) Green plants ii) Photolysis c) Light reaction iii) Bacteria and fungi g) Decomposers iv) Stomata closed d) During night v) By-products of photosynthesis f) Oxygen vi) The grana a) Is the place for light reaction of photosynthesis vii) The stroma b) Is the place for dark reaction of photosynthesis

E M B I B E

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 6

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10th ICSE

IMPORTANT

Earn 100

Two potted plants are destarched by keeping them in dark for 48 hrs and then set up as shown in the below diagrams A and B. The bell jars are made airtight by putting vaseline at the bottom. They are kept in bright sunlight for 8-10 hrs and tested for starch.

Why is KOH kept in jar A?

Important Questions on Photosynthesis

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 1

_____ (Plastids/ Leucoplasts/ Chromoplasts/ Chloroplasts) are regarded as complete photosynthetic units of plants.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 7

Define photophosphorylation.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 7

Define biosynthetic phase.

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10th ICSE

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ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 7

Define destarching.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 7

Define quantasome.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 7

Define thylakoid.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 9

Match the following:

Column I	Column II
i) Autotrophs	a) Is the place for light reaction of photosynthesis
ii) Photolysis	b) Is the place for dark reaction of photosynthesis
iii) Bacteria and fungi	c) Light reaction
iv) Stomata closed	d) During night
v) By-products of photosynthesis	e) Green plants
vi) The grana	f) Oxygen
vii) The stroma	g) Decomposers.

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10th ICSE

IMPORTANT

ICSE Self - Study in Biology>Chapter 5 - Photosynthesis>TEST YOURSELF>Q 10

Given below is the representation of a certain phenomenon in nature with four organisms (1)-(4).

$P l a n t \to g r a s s h o p p e r \to f r o g \to s n a k e \to ? (1) (2) (3) (4) (5)$