Question 1

Which of the following is a polysaccharide used for energy storage in plants?

Accepted Answer

Starch is the primary energy storage polysaccharide in plants, composed of amylose and amylopectin.

Question 2

In a polypeptide chain, amino acids are linked together by which type of chemical bond?

Accepted Answer

Peptide bonds form between the carboxyl group of one amino acid and the amino group of another through condensation.

Question 3

Which polymer is synthesized from glucose monomers and serves as the structural component in plant cell walls?

Accepted Answer

Cellulose is a linear polymer of glucose units linked by β-1,4-glycosidic bonds, providing structural rigidity to plant cell walls.

Question 4

DNA and RNA differ in their pentose sugar. DNA contains deoxyribose while RNA contains which sugar?

Accepted Answer

RNA contains ribose sugar, which has a hydroxyl (-OH) group on the 2' carbon, whereas DNA's deoxyribose lacks this group.

Question 5

The general formula for a carbohydrate is Cn(H2O)m. Which of the following is an example of a monosaccharide?

Accepted Answer

Glucose (C6H12O6) is a monosaccharide with six carbon atoms, while sucrose, lactose, and maltose are disaccharides.

Question 6

Which of the following is a disaccharide composed of glucose and fructose?

Accepted Answer

Sucrose is a disaccharide formed by condensation of one glucose and one fructose molecule, while maltose contains two glucose units and lactose contains glucose and galactose.

Question 7

The linkage between amino acids in proteins is called:

Accepted Answer

Peptide bonds form between the carboxyl group of one amino acid and the amino group of another through condensation, while glycosidic bonds link sugars in carbohydrates.

Question 8

Which polymer is formed by the condensation polymerization of ethylene glycol and adipic acid?

Accepted Answer

Polyester forms when a diol (ethylene glycol) reacts with a dicarboxylic acid (adipic acid), whereas nylon-6,6 forms from hexamethylenediamine and adipic acid.

Question 9

The primary structure of a protein is determined by the:

Accepted Answer

Primary structure refers only to the linear sequence of amino acids linked by peptide bonds; higher structures involve folding and bonding patterns.

Question 10

Which of the following carbohydrates is a polymer used structurally in plant cell walls?

Accepted Answer

Cellulose is a structural polysaccharide in plant cell walls, while starch and glycogen are storage polymers, and maltose is a simple disaccharide.

Question 11

In the formation of a triglyceride, how many ester bonds are formed when one glycerol molecule reacts with three fatty acid molecules?

Accepted Answer

Each of the three hydroxyl groups (-OH) on glycerol reacts with the carboxyl group of a fatty acid to form one ester bond, yielding three ester bonds total.

Question 12

Which statement about nucleotides is correct?

Accepted Answer

Nucleotides have three components: a nitrogenous base, a pentose sugar (ribose or deoxyribose), and a phosphate group; they are monomers of nucleic acids.

Question 13

The monomer unit of polystyrene is:

Accepted Answer

Polystyrene is formed by addition polymerization of styrene (vinylbenzene), where the C=C double bond opens to form long chains.

Question 14

A polypeptide chain contains 120 amino acid residues. How many peptide bonds are present in this polypeptide?

Accepted Answer

The number of peptide bonds in a polypeptide is always one less than the number of amino acid residues (n − 1 bonds for n residues).

Question 15

Which of the following biomolecules is a homopolymer composed of glucose units linked by α(1→4) glycosidic bonds with α(1→6) branching points?

Accepted Answer

Glycogen is a branched homopolysaccharide with α(1→4) linear linkages and frequent α(1→6) branch points, making it highly branched compared to starch.

Question 16

A nucleic acid sample contains 30% adenine. According to Chargaff's rules, what is the percentage of thymine in double-stranded DNA?

Accepted Answer

Chargaff's rule states that in double-stranded DNA, the amount of adenine equals thymine (A = T), so if adenine is 30%, thymine is also 30%.

NDA Biomolecules & Polymers

Biomolecules & Polymers — Practice Questions