Which amino acids are known to possess branched side chains?

• A. Ser, Gly, Pro
• B. Thr, Val, Ile
• C. Asp, Glu, His
• D. Cys, Met, Lys

Answer: (B)

The amino acids that possess branched side chains are valine (Val) and isoleucine (Ile), both of which have hydrocarbon branches in their side chains. Threonine (Thr) also contains a branched structure due to the presence of a hydroxyl group and an ethyl side chain, making it a branched-chain amino acid as well.

Branched-chain amino acids (BCAAs) are significant in biochemistry and nutrition, particularly in muscle metabolism, where they play a crucial role in protein synthesis and the regulation of energy production. Valine, isoleucine, and threonine are essential amino acids, meaning they must be obtained through diet because the human body cannot synthesize them.

In contrast, the other groups mentioned in the options do not contain amino acids with branched chains, highlighting the specific structure and importance of the amino acids in the correct answer.