Photosynthesis In Higher Plants Question 69
Question: The graph below shows the result of experiment in which isotopes of oxygen were used to distinguish between oxygen absorbed by plants and oxygen given out. A mixture of the oxygen istopes $ ^{16}O_2 $ and $ ^{18}O_2 $ was supplied to a suspension of the unicellular alga Chlorella which had previously been exposed to $ ^{16}O_2 $ only. During the following hour changes in the concentration of these gases in the suspension were measured. The $ ^{18}O_2 $ concentration fell in light because it was:
Options:
A) Undergoing radioactive decay to from $ ^{16}O_2 $
B) Absorbed in respiration but was not being produced in photosynthesis.
C) Absorbed in respiration slower than it was being produced in photosynthesis.
D) Absorbed as C $ ^{18}O_2 $ in photosynthesis.
Show Answer
Answer:
Correct Answer: B
Solution:
[b] The oxygen produced in photosynthesis is produced from the splitting of a water molecule by light energy, and not directly from the oxygen taken in during respiration.
BETA
