CameraIcon

SearchIcon

MyQuestionIcon

280

You visited us 280 times! Enjoying our articles? Unlock Full Access!

Experiments conducted to prove the formation of starch in plants

Both the plan...

Question

Both the plants 'A' and 'B' were kept in sunlight after watering. The part of the leaf of plant 'B' which was inserted in the glass bottle containing KOH(Potassium hydroxide) did not turn blue in the iodine test/ starch test, indicating the absence of starch. The part of the leaf outside the bottle turns blue in the said test. Photosynthesis didn't occur in that part of the leaf due to the non-availability of _________.

A

Sunlight

No worries! We‘ve got your back. Try BYJU‘S free classes today!

B

Chlorophyll

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C

C O_{2}

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

D

Water

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is C $C O_{2}$
Here, this experiment was done to check the importance of carbon dioxide in photosynthesis. The carbon dioxide is reduced to formed carbohydrate i.e starch.
The part of the leaf tested negative because the KOH absorbs the CO₂ present in the surrounding and as a result, there is no photosynthesis.
So, the correct option is 'CO₂'

Suggest Corrections

thumbs-up

0

Similar questions

Q. A portion of destarched leaf of a potted plant was covered with a black strip of paper. The plant was then exposed to sunlight for six hours and then tested for starch. It was observed that:
(1) both covered and uncovered parts of leaf turned blue-black
(2) both covered and uncovered parts of leaf turned yellow-brown
(3) only the uncovered part of leaf turned blue-black
(4) only the covered part of leaf turned blue-black

Q. In the experiment to show that sunlight is necessary for photosynthesis:
(a) What is done to destarch the green leaves of the potted plant initially?
(b) What is done to a part of destarched leaf so that photosynthesis may not take place in that part of the leaf (before keeping the potted plant in sunlight)?
(c) How is chlorophyll removed from the green leaf before further testing?
(d) Which reagent is used to test the presence/absence of starch in the parts of experimental leaf?

Q. The non-green part of a variegated leaf, after the starch test, exhibits colour due to the absence of

Q. In an experiment, a destarched, long and narrow green leaf (still attached to a potted plant) is introduced into a wide-mouthed glass bottle through an airtight cork. The glass bottle contains some potassium hydroxide solution in its lower part (but the leaf remains above this solution). The whole set-up is placed in sunlight for 2-3 days. The leaf is then taken out. After removing chlorophyll, the leaf is treated with iodine solution. No blue-black colour is produced in the leaf.
(a) Which substance could not be synthesised in the green leaf?
(b) What is the function of potassium hydroxide solution inside the glass bottle?
(c) Which condition necessary for photosynthesis is not fulfilled in this experiment?

Why is the leaf boiled in water and alcohol before testing for the presence of starch?

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

BIOLOGY

Watch in App

explore_more_icon

Explore more

Experiments conducted to prove the formation of starch in plants

Standard VIII Biology

Join BYJU'S Learning Program

CrossIcon