Photosynthesis In Higher Plants Question 22

Question: Assertion : The atmospheric concentration of $ CO_2 $ at which photosynthesis just compensates for respiration is referred to as $ CO_2 $ compensation point. Reason : The $ CO_2 $ compensation point is reached when the amount of $ CO_2 $ uptake is less than that generated through respiration because the level of $ CO_2 $ in the atmosphere is more than that required for achieving $ CO_2 $ compensation point.

Options:

A) If both the assertion and the reason are true and the reason is a correct explanation of the assertion

B) If both the assertion and reason are true but the reason is not a correct explanation of the assertion

C) If the assertion is true but the reason is false

D) If both the assertion and reason are false

Show Answer

Answer:

Correct Answer: C

Solution:

At very low $ CO_2 $ concentration photosynthesis is strongly limited by the low $ CO_2 $ while respiratory rates are unaffected.

As a result there is a negative balance between $ CO_2 $ fixed by photosynthesis and $ CO_2 $ produced by respiration and a net efflux of $ CO_2 $ compensation point.

By increasing the atmospheric concentration of $ CO_2 $ at which photosynthesis just compensate for respiration is referred to as $ CO_2 $ compensation point.