Which statement about alanine is true?

• A. It is nonessential and can be synthesized by the body.
• B. It is essential and must be obtained in the diet.
• C. It is a carbohydrate.
• D. It is the primary energy source during rest.

Answer: (A)

Alanine is a nonessential amino acid, meaning the body can synthesize it and does not require it from the diet. It can be made from pyruvate through transamination, so the body has the means to produce it as needed. In metabolism, alanine participates in the glucose-alanine cycle: muscles release alanine during glycolysis, and the liver converts it back to glucose to help maintain blood sugar. That’s why the statement that alanine is nonessential and can be synthesized is true.

It isn’t a carbohydrate—amino acids are the building blocks of proteins, not sugars. It isn’t the primary energy source during rest—fatty acids and glucose are the main fuels then. And it isn’t essential and must be obtained from the diet, since the body can make alanine.