[Campbell Biology P.231] Based on Figure 9.18, which of the following statements about the c... | Practice Question

Based on Figure 9.18, which of the following statements about the catabolism of macromolecules is correct?

  • A: Proteins directly enter the citric acid cycle without prior modification.
  • B: Fats are primarily broken down into glycerol and fatty acids, both of which enter glycolysis.
  • C: Carbohydrates are first converted to sugars, which then enter glycolysis as glucose.
  • D: All breakdown products directly enter oxidative phosphorylation.

Explanation

Figure 9.18 illustrates that carbohydrates are broken down into sugars, which then primarily enter glycolysis as glucose. Proteins are converted to amino acids and then to intermediates of glycolysis or the citric acid cycle after deamination. Fats are broken into glycerol which enters glycolysis and fatty acids which enter as acetyl CoA into the citric acid cycle . The entire process funnels through glycolysis and the citric acid cycle before oxidative phosphorylation.