Class 7 Science: Life Processes in Plants MCQs (NCERT)
105 practice questions on Life Processes in Plants, a chapter in the NCERT Class 7 Science textbook, with a dedicated set on Photosynthesis. Every question includes a written explanation. Pick a topic below, or try the samples first.
Moist germinating seeds are shut inside a sealed flask overnight. In the morning the air of the flask is passed through clear limewater, which turns milky. This shows that the seeds have
Agiven out carbon dioxide while respiring
Bused up all the carbon dioxide in the flask
Cgiven out oxygen while making food
Dstored starch inside the flask
Show answer and explanation
Correct answer: A - given out carbon dioxide while respiring
Limewater turns milky only where carbon dioxide is present, and the seeds in the dark flask could only have produced it by respiring. They made no food in the sealed dark flask, so they added carbon dioxide rather than using it up, and starch cannot be tested by limewater.
Q2
hard
A plant is first kept in the dark until its leaves hold no starch. A strip of black paper is then clipped over part of one leaf and the plant is left in sunlight for a whole day. When that leaf is tested with iodine, the result will be that
Athe covered part turns blue-black while the uncovered part does not
Bthe uncovered part turns blue-black while the covered part does not
Cno part of the leaf turns blue-black
Dthe whole leaf turns blue-black
Show answer and explanation
Correct answer: B - the uncovered part turns blue-black while the covered part does not
Only the part reached by sunlight could make food, so only that part stores starch and gives the blue-black colour. The covered strip stayed in the dark, so it stays pale, and since one part did receive light, neither the whole leaf nor none of it can give the colour.
Q3
medium
A leaf that has been making food turns blue-black when iodine solution is dropped on it. This colour shows the presence of
Achlorophyll
Boxygen
Ccarbon dioxide
Dstarch
Show answer and explanation
Correct answer: D - starch
The blue-black colour appears only where starch is present, so the test shows that food has been made and stored in the leaf. Oxygen and carbon dioxide are gases that iodine does not detect, and chlorophyll is deliberately removed before the test is carried out.
Q4
easy
A money plant is kept inside a dark cupboard and watered regularly. Over a few weeks it turns pale and weak. The factor missing here is
Asoil
Bair
Csunlight
Denough water
Show answer and explanation
Correct answer: C - sunlight
The plant is being watered and is sitting in soil with air all around it, so the only thing it lacks inside the cupboard is light. Without light a green plant cannot make food, and it slowly loses its colour and its strength.
Q5
easy
Water taken in by the roots reaches the leaves by passing through the
Aroot hairs alone
Bstem
Cfruits
Dflowers
Show answer and explanation
Correct answer: B - stem
The stem is the passage that joins the roots to the leaves and carries water upward through it. Root hairs are where water enters at the very beginning, and flowers and fruits are not on the path from the soil to the leaves.
Q6
easy
The food made in the leaves of a plant is carried
Aout of the plant and into the soil
Bonly to the flowers of the plant, to help make fruits and seeds
Cto all the other parts of the plant, including the roots
Donly upward to the topmost leaves that are still growing
Show answer and explanation
Correct answer: C - to all the other parts of the plant, including the roots
Every part of a plant needs food, and the food made in the leaves is carried to the stem, the roots, the flowers and the fruits alike. Sending it only to the flowers or only upward would starve the rest, and a plant does not pour its food into the soil.
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