Consider the following tripeptide:

a. Circle the N-terminal amino acid, and give its name. Draw a square around the C-terminal amino acid, and give its name.

Verified step by step guidance

1. Step 1: Understand the structure of a tripeptide. A tripeptide consists of three amino acids linked by peptide bonds. The N-terminal amino acid is the one with a free amino group (-NH2), while the C-terminal amino acid is the one with a free carboxyl group (-COOH).
2. Step 2: Examine the provided image of the tripeptide. Identify the amino acid at the N-terminal (leftmost side of the structure) by locating the free amino group (-NH2). Circle this amino acid and note its name based on its side chain and structure.
3. Step 3: Identify the amino acid at the C-terminal (rightmost side of the structure) by locating the free carboxyl group (-COOH). Draw a square around this amino acid and note its name based on its side chain and structure.
4. Step 4: For the middle amino acid, observe its structure and confirm that it is connected to the N-terminal and C-terminal amino acids via peptide bonds. This amino acid does not have free amino or carboxyl groups.
5. Step 5: Review the names of the N-terminal and C-terminal amino acids you identified, ensuring they match the structural features and side chains visible in the image.

Key Concepts

N-terminal and C-terminal

The N-terminal refers to the end of a peptide or protein that has a free amino group (-NH2), while the C-terminal is the end with a free carboxyl group (-COOH). In a tripeptide, the N-terminal amino acid is the first in the sequence, and the C-terminal is the last. Identifying these ends is crucial for understanding the structure and function of peptides.

Amino Acids

Amino acids are the building blocks of proteins and peptides, consisting of a central carbon atom, an amino group, a carboxyl group, a hydrogen atom, and a variable side chain (R group). Each amino acid has a unique side chain that determines its properties and role in protein structure. Recognizing the specific amino acids at the N- and C-termini is essential for understanding the peptide's characteristics.

Peptide Structure

Peptides are short chains of amino acids linked by peptide bonds, formed through a dehydration reaction between the amino group of one amino acid and the carboxyl group of another. The sequence and arrangement of amino acids in a peptide dictate its three-dimensional structure and biological function. Understanding peptide structure is vital for analyzing how the N- and C-terminal amino acids influence the overall properties of the tripeptide.