Multiple Choice
In aerobic metabolism of one molecule of glucose, which pathway produces the greatest total number of NADH molecules (including NADH produced by its associated reactions)?
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Review 3: Pyruvate & Fatty Acid Oxidation, Citric Acid Cycle, & Glycogen Metabolism
Citric Acid Cycle 1
Multiple Choice
In cellular respiration, what is the primary function of the Krebs (citric acid) cycle?
A
To synthesize acetyl-CoA from fatty acids and store energy primarily as glycogen
B
To use oxygen as the terminal electron acceptor and pump protons across the inner mitochondrial membrane
C
To oxidize acetyl-CoA to while producing reduced electron carriers ( and ) and a small amount of /
D
To generate most of the cell’s directly by substrate-level phosphorylation of glucose to pyruvate
Verified step by step guidance1
Understand that the Krebs cycle (also called the citric acid cycle) is a central metabolic pathway in cellular respiration that processes acetyl-CoA derived from carbohydrates, fats, and proteins.
Recognize that the primary role of the Krebs cycle is to oxidize acetyl-CoA, which means it breaks down acetyl-CoA molecules to release energy and produce carbon dioxide (CO\(\textsubscript{2}\)) as a waste product.
Identify that during this oxidation process, the Krebs cycle generates reduced electron carriers, specifically NADH and FADH\(\textsubscript{2}\), which are crucial for the next stage of cellular respiration (the electron transport chain).
Note that the Krebs cycle also produces a small amount of ATP (or GTP) directly through substrate-level phosphorylation, but this is not the main source of ATP in cellular respiration.
Distinguish the Krebs cycle's function from other processes: it does not synthesize acetyl-CoA from fatty acids, nor does it use oxygen directly as the terminal electron acceptor (this happens in the electron transport chain).
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