Which amino acid is most likely to participate in hydrogen bonding with water?

• A. Serine
• B. Leucine
• C. Valine
• D. Phenylalanine

Answer: (A)

Verified step by step guidance

1. Understand the concept of hydrogen bonding: Hydrogen bonds occur when a hydrogen atom covalently bonded to an electronegative atom (like oxygen or nitrogen) interacts with another electronegative atom. Amino acids with polar side chains are more likely to form hydrogen bonds with water.
2. Analyze the side chains of the given amino acids: Serine has a hydroxyl (-OH) group, which is polar and capable of forming hydrogen bonds. Leucine, Valine, and Phenylalanine have nonpolar side chains, making them less likely to participate in hydrogen bonding with water.
3. Recall the properties of polar and nonpolar amino acids: Polar amino acids, such as Serine, interact well with water due to their ability to form hydrogen bonds. Nonpolar amino acids, like Leucine, Valine, and Phenylalanine, are hydrophobic and do not readily form hydrogen bonds with water.
4. Compare the amino acids: Serine's hydroxyl group makes it the most likely candidate for hydrogen bonding with water, while the other amino acids lack functional groups that can form hydrogen bonds.
5. Conclude that Serine is the correct answer based on its polar side chain and ability to form hydrogen bonds with water.