How does the reductive (reverse) TCA cycle participate in carbon fixation?
A) Some of the TCA reactions occur in reverse, assimilating small amounts of CO₂.
B) CO₂ assimilation uses up TCA intermediates for anabolic pathways.
C) Reverse TCA regenerates succinyl-CoA, which may enter gluconeogenesis.
D) A large amount of ATP is generated.
E) All reactions take place in a carboxysome.

Question

Quizplus · Accepted Answer

The reductive TCA cycle includes some reactions that occur in reverse and assimilate small amounts of CO₂, contributing to carbon fixation.

Answer: C 
 The reverse TCA cycle regenerates succinyl-CoA, which may enter gluconeogenesis, contributing to carbon fixation.

Therefore, the best choices are A and C.

How Does the Reductive (Reverse) TCA Cycle Participate in Carbon