List the amino acids with side chains that are capable of hydrogen bonding. Draw an example of two of these amino acids hydrogen bonding to one another. For each one, draw a hydrogen bond to water in a separate sketch. Refer to Section 8.2 for help with drawing hydrogen bonds.

Verified step by step guidance

1. Identify amino acids with side chains capable of hydrogen bonding. These typically include amino acids with polar side chains such as serine, threonine, tyrosine, asparagine, glutamine, and histidine.
2. Choose two amino acids from the list identified in the previous step. For example, serine and threonine.
3. Draw the structure of the first amino acid (e.g., serine) and highlight its side chain. Indicate the hydrogen bond donor and acceptor atoms in the side chain.
4. Draw the structure of the second amino acid (e.g., threonine) and highlight its side chain. Indicate the hydrogen bond donor and acceptor atoms in the side chain.
5. Illustrate the hydrogen bond between the side chains of the two amino acids. Then, separately, draw each amino acid interacting with a water molecule, showing the hydrogen bond between the amino acid side chain and water.

Key Concepts

Amino Acids and Side Chains

Amino acids are organic compounds that serve as the building blocks of proteins. Each amino acid has a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group). The properties of the side chains determine the amino acid's characteristics, including its ability to participate in hydrogen bonding, which is crucial for protein structure and function.

Hydrogen Bonding

Hydrogen bonding is a type of weak chemical bond that occurs when a hydrogen atom covalently bonded to an electronegative atom, such as oxygen or nitrogen, experiences an attraction to another electronegative atom. This interaction is significant in biological systems, as it stabilizes the structures of proteins and nucleic acids, and facilitates interactions with water molecules, influencing solubility and reactivity.

Hydrophilic and Hydrophobic Interactions

Hydrophilic interactions refer to the affinity of molecules or side chains that can form hydrogen bonds with water, making them soluble in aqueous environments. In contrast, hydrophobic interactions involve nonpolar side chains that do not interact favorably with water. Understanding these interactions is essential for predicting how amino acids behave in proteins and how they interact with their environment, including water.