Besides being catabolized further, what else can the pyruvate produced by glycolysis become?
AThe lipid cholesterol
BThe nucleotide adenine
CThe amino acid alanine
DThe sugar galactose
Answer & Solution
Correct answer: C. The amino acid alanine
1. The last step of glycolysis is catalysed by pyruvate kinase.
2. The pyruvate produced can proceed to be catabolized or be converted into the amino acid alanine.
3. If no more energy is needed and alanine is in adequate supply, the enzyme is inhibited.
4. So the fate of pyruvate feeds back onto the enzyme that made it.
5. Cholesterol synthesis starts from acetyl groups rather than from pyruvate directly.
6. Galactose is a dietary sugar that feeds into glycolysis, so it enters the pathway rather than leaving it.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.7 Regulation of Cellular Respiration_
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