Amino Acids and Peptide Bonds in a Linear Tetrapeptide

In order to understand the correct answer to this question, let's break it down into two parts: the number of amino acids and the number of peptide bonds in a linear tetrapeptide.

Number of Amino Acids
Amino acids are the building blocks of proteins, and they are linked together through peptide bonds to form polypeptide chains. Each amino acid consists of an amino group (-NH2), a carboxyl group (-COOH), and a side chain (R-group) that varies for each amino acid.

In a linear tetrapeptide, the "tetra" prefix indicates that there are four amino acids present. Therefore, the correct answer to the first part of the question is option 'D' - 4 amino acids.

Number of Peptide Bonds
Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of another amino acid. This bond is formed through a condensation reaction, where a water molecule is eliminated.

To determine the number of peptide bonds in a linear tetrapeptide, we need to consider the number of amino acids present. In this case, we have four amino acids. Since each peptide bond connects two amino acids, we can calculate the number of peptide bonds using the formula:

Number of Peptide Bonds = Number of Amino Acids - 1

Using this formula, the number of peptide bonds in a linear tetrapeptide would be:

Number of Peptide Bonds = 4 - 1 = 3

Therefore, the correct answer to the second part of the question is option 'D' - 3 peptide bonds.

Summary
In summary, a linear tetrapeptide consists of four amino acids and three peptide bonds. The correct answer to the question is option 'D'. It is important to understand the basic concepts of amino acids, peptide bonds, and protein structure to accurately determine the number of amino acids and peptide bonds in a given molecule.