Question

Each round of the citric acid cycle begins when the four-carbon molecule oxaloacetate is converted to the six-carbon molecule citrate. As the cycle progresses, two carbons are eliminated to regenerate the oxaloacetate. The added carbon is supplied by _____ and the two eliminated carbons are released as _____.

A. CO₂; acetyl-CoA
B. ATP; acetyl-CoA
C. Acetyl-CoA; CO₂
D. CO₂; NADH
E. CO₂; pyruvate

Answer 1

C. Acetyl-CoA; CO₂

Step-by-step explanation:

Acetyl-CoA undergoes into the citric acid cycle and combines with oxaloacetate to produce citrate which is a 6 carbon molecule. Citrate then undergoes 2 steps and yields alpha- ketoglutarate and removal of carbon dioxide takes place. Alpha- ketoglutarate then undergoes reaction and yields succinyl CoA which is 4 carbon molecule and produces 1 molecule of carbon dioxide.

Hence, the correct option is C