Join thousands of students who trust us to help them ace their exams!
Multiple Choice
In the citric acid (Krebs) cycle, which molecule is released as the primary waste product for each turn of the cycle?
A
Carbon dioxide ()
B
Acetyl-CoA
C
Lactate
D
Urea
0 Comments
Verified step by step guidance
1
Understand the citric acid (Krebs) cycle as a central metabolic pathway that oxidizes acetyl-CoA to produce energy, releasing waste products in the process.
Recall that during each turn of the cycle, acetyl-CoA (a 2-carbon molecule) combines with oxaloacetate to form citrate, which undergoes a series of transformations.
Identify that as the cycle progresses, two carbon atoms are removed from the intermediates in the form of carbon dioxide (CO\_2), which is the primary waste product released.
Recognize that lactate and urea are not products of the citric acid cycle: lactate is produced during anaerobic glycolysis, and urea is produced in the urea cycle for nitrogen excretion.
Conclude that the molecule released as the primary waste product for each turn of the citric acid cycle is carbon dioxide (CO\_2).