Question

how would you predict that blocking the oxidation of pyruvate would affect the levels of oxaloacetate and citrate in the citric acid cycle (see the figure)?

both oxaloacetate and citrate will decrease.

there will be no change in the levels of oxaloacetate and citrate.

oxaloacetate will accumulate, and citrate will decrease.

both oxaloacetate and citrate will accumulate.

oxaloacetate will decrease, and citrate will accumulate.

Explanation:

Step1: Understand the citric acid cycle

Pyruvate oxidation produces acetyl - CoA. Acetyl - CoA combines with oxaloacetate to form citrate.

Step2: Analyze the effect of blocking pyruvate oxidation

If pyruvate oxidation is blocked, there is no acetyl - CoA production. Since acetyl - CoA is needed to form citrate from oxaloacetate, citrate production will decrease. Without being used to form citrate, oxaloacetate will accumulate.

Answer:

Oxaloacetate will accumulate, and citrate will decrease.