Question

Pyruvate can be converted into many other molecules by various biosynthetic and metabolic pathways, which makes it a central hub in the regulation of cellular metabolism. Which of the following molecules is made from pyruvate?

A) oxaloacetate
B) ethanol
C) lactate
D) NADH

Answer 1

Pyruvate can be converted into either oxaloacetate, ethanol, or lactate, depending on cellular conditions. NADH is a byproduct of pyruvate's conversion into acetyl CoA, not a direct conversion product of pyruvate.

Step-by-step explanation:

The fate of pyruvate in cellular metabolism is a crucial aspect in understanding how energy is produced and managed within cells. Pyruvate stands at a crossroad, able to be converted into several different molecules depending on the cellular conditions. Here are a few pathways where pyruvate undergoes transformation:

• Oxaloacetate: Pyruvate can be converted into oxaloacetate, which is a central component of the citric acid cycle (Krebs cycle).
• Ethanol: Under anaerobic conditions, such as those in yeast cells, pyruvate can be converted into ethanol through alcoholic fermentation.
• Lactate: During intense exercise when oxygen is scarce, pyruvate is reduced to lactate in the muscle cells by the enzyme lactate dehydrogenase.

Although NADH is closely associated with the process where pyruvate is converted into acetyl CoA (by the pyruvate dehydrogenase complex), NADH itself is not made from pyruvate, but rather, is generated during this conversion as pyruvate is decarboxylated and oxidized.