Figure 7.1
-In the citric acid cycle (see Figure 7.1),beginning with one molecule of isocitrate and ending with fumarate,how many ATP molecules can be made through substrate-level phosphorylation?
A)1
B)2
C)11
D)12
E)24

Question

Figure 7.1
-In the citric acid cycle (see Figure 7.1),beginning with one molecule of isocitrate and ending with fumarate,how many ATP molecules can be made through substrate-level phosphorylation?
A)1 
B)2 
C)11 
D)12 
E)24

Quizplus · Accepted Answer

In the citric acid cycle, starting from isocitrate and ending with fumarate, no ATP is directly produced through substrate-level phosphorylation. However, the conversion of succinyl-CoA to succinate (which is just after the production of fumarate in the cycle) is associated with the generation of GTP, which can be readily converted to ATP. Therefore, considering the specific start and end points given in the question, the answer is 0, but since that option is not available, the closest correct answer reflecting direct ATP production through substrate-level phosphorylation in the cycle would be 1 (A), assuming the question implies the entire cycle's completion or a slight misinterpretation of the cycle's steps.

Figure 7.1 -In the Citric Acid Cycle (See Figure 7.1),beginning with One