Which of the following statements are incorrect?
(A) Amylose is a component of cellulose.
(B) Starch is a polymer of α-glucose.
(C) Proteins are polymers of β-amino acids.
(D) In fructose, the ring formed by the addition of the –OH at C5 to the >C=O group is six-membered.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (C) and (D) only
(A) Amylose is a component of cellulose. — False. Amylose is one of the two components of starch (with amylopectin), not of cellulose.
(B) Starch is a polymer of α-glucose. — True. Starch is built of α-glucose units.
(C) Proteins are polymers of β-amino acids. — False. Proteins are polymers of α-amino acids, in which the amino group is on the carbon next to the carboxyl group.
(D) In fructose, the ring formed by the addition of the –OH at C5 to the >C=O group is six-membered. — False. The keto group of fructose is at C2, so the ring closed by the C5 –OH holds C2, C3, C4, C5 and one oxygen: a five membered ring, the furanose ring.
NCERT (2026-27 edition):
10.1.4 Polysaccharides – “(i) Starch: Starch is the main storage polysaccharide of plants. … It is a polymer of α-glucose and consists of two components— Amylose and Amylopectin.”
10.2 Proteins – “… All proteins are polymers of α-amino acids.”
10.1.2.2 Fructose – “It also exists in two cyclic forms which are obtained by the addition of –OH at C5 to the (>C=O) group. The ring, thus formed is a five membered ring and is named as furanose with analogy to the compound furan.”