Which of the following biomolecules does have a phosphodiester bond?

(1) Fatty acids in a diglyceride

(2) Monosaccharides in a polysaccharide

(3) Amino acids in a polypeptide

(4) Nucleic acids in a nucleotide

The chitinous exoskeleton of arthopods is formed by the polymerisation of 

(1) keratin sulphate and chondroitin sulphate

(2) D-glucosamine

(3) N-acetyl glucosamine

(4) lipoglycans

Which one of the following statements is correct, with reference to enzymes?

(1) Apoenzyme = Holoenzyme + Coenzyme

(2) Holoenzyme = Apoenzyme + Coenzyme

(3) Coenzyme = Apoenzyme + Holoenzyme

(4) Holoenzyme = Coenzyme + Cofactor

Which of the following is not a polymeric substance?

(1) Nucleic acid               

(2) Proteins

(3) Polysaccharides           

(4) Lipids

A non-proteinaceous enzyme is

(1) lysozyme           

(2) ribozyme

(3) ligase               

(4) deoxyribonuclease

Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins?

(1) Hydrogen bonds

(2) Electrostatic interaction

(3) Hydrophobic interaction

(4) Ester bonds

Which of the following describes the graph correctly?

(1) Endothermic reaction with energy A in the presence of enzyme and B in the absence of enzyme

(2) Exothermic reaction with energy A in the presence of enzyme and B in the absence of enzyme

(3) Endothermic reaction with energy A in the absence of enzyme and B in the presence of enzyme

(4) Exothermic reaction with energy A in the absence of enzyme and B in the presence of enzyme

Which one of the following statements is wrong?

(1) Cellulose is a polysachharide

(2) Uracil is a pyrimidine

(3) Glycine is a sulphur containing amino acid

(4) Sucrose is a diasaccharide

A typical fat molecule is made up of

(1) One glycerol and three fatty acid molecules

(2) One glycerol and one fatty acid molecule

(3) Three glycerol and three fatty acid molecules

(4) Three glycerol molecules and one fatty acid molecule

Which one of the following statement is incorrect ?

1. A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor.

2. In competitive inhibition the inhibitor molecule is not chemically changed by the

enzyme.

3. The competative inhibitor does not affect the rate of breakdown of the enzyme-

substrate complex.

4. The presence of the competitive inhibitor decreases the k_m of the enzyme for the

substrate.