Question 1

Which of the following is an amino acid containing sulfur?

Accepted Answer

Cysteine is a sulfur-containing amino acid. It contains a thiol group, which is crucial for forming disulfide bonds in proteins, helping to stabilize their tertiary structure. Other common sulfur-containing amino acids include methionine.

Question 2

The bond between two amino acids in a polypeptide chain is called:

Accepted Answer

A peptide bond is formed between the carboxyl group of one amino acid and the amino group of the next amino acid with the release of a water molecule (condensation reaction).

Question 3

Which of the following is a reducing sugar?

Accepted Answer

Glucose is a reducing sugar because it has a free aldehyde group that can reduce oxidizing agents like Tollens' or Benedict's reagent. Sucrose is a non-reducing sugar.

Question 4

Lipids are insoluble in water because lipids are:

Accepted Answer

Lipids are hydrophobic because they are composed mostly of non-polar hydrocarbon chains, which do not interact favorably with polar water molecules.

Question 5

The primary structure of a protein refers to:

Accepted Answer

The primary structure of a protein is the linear sequence of amino acids held together by peptide bonds in the polypeptide chain.

Biomolecules — NCERT Class 11 Biology Important Questions & Revision Notes