Which statement about the Krebs cycle is accurate?

Which statement about the Krebs cycle is accurate?

• A. It is the first stage of cellular respiration in which glucose is split
• B. Produces molecules that carry energy to the second part of cellular respiration
• C. Occurs in the cytoplasm and uses oxygen to produce lactic acid
• D. Uses sunlight to convert carbon dioxide into glucose

Answer: (B)

The Krebs cycle channels energy from acetyl-CoA into carrier molecules that feed the next stage of cellular respiration. As it runs, it produces NADH and FADH2, high-energy carriers that hand off electrons to the electron transport chain, where most ATP is made. This connection to the second part of respiration is what makes the statement accurate: the cycle’s output includes molecules that carry energy forward to drive further ATP production. It isn’t the first stage of respiration—that initial glucose-splitting process occurs in the cytoplasm (glycolysis). The Krebs cycle itself takes place in the mitochondrial matrix and does not generate lactic acid; lactic acid formation happens during fermentation when oxygen is limited. And it doesn’t involve sunlight or photosynthesis, which are about converting light energy into chemical energy to make glucose.

The Krebs cycle channels energy from acetyl-CoA into carrier molecules that feed the next stage of cellular respiration. As it runs, it produces NADH and FADH2, high-energy carriers that hand off electrons to the electron transport chain, where most ATP is made. This connection to the second part of respiration is what makes the statement accurate: the cycle’s output includes molecules that carry energy forward to drive further ATP production.

It isn’t the first stage of respiration—that initial glucose-splitting process occurs in the cytoplasm (glycolysis). The Krebs cycle itself takes place in the mitochondrial matrix and does not generate lactic acid; lactic acid formation happens during fermentation when oxygen is limited. And it doesn’t involve sunlight or photosynthesis, which are about converting light energy into chemical energy to make glucose.