Which of the following is an example of a sulphur-containing amino acid?

Cysteine

The answer is (3) cysteine.

Cysteine is an amino acid that contains a sulfur atom in its side chain. The sulfur atom is attached to the amino group of the amino acid. Cysteine is one of the two sulfur-containing amino acids, the other being methionine.

Lysine, serine, and tyrosine do not contain sulfur atoms in their side chains. Therefore, the only option that is a sulfur-containing amino acid is cysteine.

Here are some of the characteristics of cysteine:

• Cysteine is a non-essential amino acid, which means that it can be synthesized by the body.
• Cysteine is a sulfhydryl amino acid, which means that it has a sulfur atom in its side chain that can form disulfide bonds with other cysteine molecules.
• Cysteine is involved in a number of important biological processes, including protein folding, signal transduction, and antioxidant defense.