Question

An example of a sulphur containing amino acid is:
A.lysine
B.serine
C.cysteine
D.tyrosine

Answer 1

Hint: Amino acids are organic compounds that bind to form proteins. The building blocks of life are amino acids and proteins. Amino acids are left over after proteins are digested. Amino acids are used by the human body to produce proteins that help in the breakdown of food.

Complete answer:
A.Lysine: Lysine is a vital amino acid in human and animal feeding, and it is present in high quantities in beef, poultry, and dairy products, although it is found in small amounts in plant proteins. Lysine does not contain sulphur, and hence this is not the correct answer.

B.Serine: Serine differs from cysteine only due to oxygen which replaces the sulphur, and hence does not readily form dioxide bonds. Serine does not contain sulphur, and hence this is not the correct answer.

C.Cysteine: Cysteine is a non-essential amino acid, which means that the human body can produce it. Cysteine is one of the few sulphur-containing amino acids. This enables cysteine to form a unique bond with other amino acids and preserve the structure of proteins in the body. Hence this is the correct answer.

D.Tyrosine: Tyrosine is made in the body from phenylalanine, an amino acid. Dairy items, meats, fish, eggs, nuts, beans, peas, and wheat all contain tyrosine. Tyrosine does not contain sulphur, and hence this is not the correct answer.

An example of a sulphur containing amino acid is Cysteine. Therefore, the correct option is C) cysteine.

Note:
The four sulphur-containing amino acids are methionine, cysteine, homocysteine, and taurine, but only the first two are absorbed into proteins. Sulphur is of the same periodic table group as oxygen, but it is much less electronegative.