Question

Pick out the wrong statement.
A) Proteins are linear chains of amino acids linked by peptide bonds
B) Cellulose is a homopolymer
C) Inulin is a polymer of glucose
D) RuBisCO is the most abundant protein in the whole biosphere
E) Chitin is a heteropolymer

Answer 1

Hint:All the compounds given in the question are polymers. The analysis of the monomeric units of each of these polymers will lead to the answer. The option where the polymeric nature of the compound is not mentioned, study about the compound itself to decide the correctness of the statement.

Complete answer:
Let us look at each option one by one.
Proteins are formed from the three dimensional spatial arrangement of peptides which are a linear chain of amino acid molecules. Therefore, the statement ‘proteins are linear chains of amino acids linked by peptide bonds’ is correct.

Cellulose is a macromolecule composed of β linked D-glucose monomeric units. Hence, cellulose is indeed a homopolymer. Therefore, this statement is correct.

Inulin is a heteropolymer made of β (2,1) linked glucosyl and repetitive fructosyl units. Hence, Inulin is not a polymer of just glucose. Therefore, this statement is wrong.

RuBisCO (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is an enzyme found in almost all photosynthetic plants around the globe and is responsible for the vast majority of the $CO_2$ fixation. Hence, it is considered as the most abundant protein in the whole biosphere. Therefore, this statement is correct.

Chitin is a homopolysaccharide made of repeated units of N-acetylglucosamine, a derivative of glucose. Hence, chitin is not a heteropolymer. Therefore, this statement is wrong.

Thus, the correct answers for this question are (C) Inulin is a polymer of glucose and (E) Chitin is a heteropolymer.

Note:In the functional sense, proteins are not exactly long chains of amino acids. Proteins are formed when multiple peptides which are amino acid chains spatially aggregate together to form a functionally active structure.