Which statement about nonessential amino acids is correct?

• A. They must be obtained from the diet
• B. They can be made by the body
• C. They are required in larger amounts than essential amino acids
• D. They cannot be synthesized

Answer: (B)

Nonessential amino acids are those the body can synthesize. Because metabolic pathways allow the body to create these amino acids from other molecules, they do not need to be supplied in the diet under normal conditions. That's why the statement that they can be made by the body is correct.

In practice, the body builds many of these amino acids through transamination reactions, using intermediates from energy metabolism (for example, pyruvate can be converted to alanine, and alpha-ketoglutarate to glutamate). Some nonessential amino acids can become conditionally essential in certain situations (like illness or rapid growth) when the body's synthesis cannot meet needs, but under typical conditions they are made endogenously.

The other statements are not correct because nonessential amino acids do not have to come from the diet, they can be synthesized; and the idea that they are required in larger amounts than essential amino acids isn’t the defining distinction or a general rule.