Question

Two molecules of CO2 are produced after the completion of a single citric acid reaction cycle. Where does the required oxygen come from?

a) Water
b) Carbon dioxide
c) Oxygen gas
d) Glucose

Answer 1

The required oxygen in the citric acid cycle comes from the oxygen gas in the environment. Hence the correct answer is option C

Step-by-step explanation:

The required oxygen in the citric acid cycle comes from the oxygen gas in the environment. During the citric acid cycle, two carbon dioxide molecules are released on each turn of the cycle. These carbon dioxide molecules are formed as a result of the removal of carbon atoms from the glucose molecule. The carbon atoms are then combined with oxygen atoms to form carbon dioxide.

Hence the correct answer is option C