2018 Collated Biomolecules & Enzymes MCQ QP+MS.pdf

2018 Biomolecules and Enzymes MCQ2018 / H2 / ACJC PRELIM / P1 Q41Proteins can be categorised as globular or fibrous, depending on their structure. How many of the following statements describes fibrous proteins only?1Monomers are linked by peptide bonds formed during translation2Long molecules which are insoluble in water3Helical molecules consisting of non-repeating sequences of amino acids4Contains hydrogen bonds between polypeptidesA0B1C2D32018 / H2 / ACJC PRELIM / P1 Q52Malic acid is produced by a series of enzyme-catalysed reactions. The addition of malonic acid results in an accumulation of succinic acid, a near absence of both fumaric acid and malic acid, and has no effect on the concentration of oxoglutaric acid.Further addition of fumaric acid results in the formation of malic acid.What does this information indicate about malonic acid?AIt is an inhibitor of enzyme 1.BIt catalyses the formation of succinic acid.CIt is an inhibitor of enzyme 2.DIt reacts with fumaric acid.

2018 / H2 / AJC PRELIM / P1 Q23Which diagram shows the linking of two monomers together to form cellulose? 2018 / H2 / AJC PRELIM / P1 Q34The diagram shows the structure of a lipid molecule. Which statements are not correct?1The fatty acid occupying the central (second) position of the lipid molecule has a molecular formula of C16H32O2, while the fatty acid occupying the other two positions has a molecular formula of C18H34O2.2More ATP can be obtained from the lipid molecule than equal mass of glycogen.

3The molecule is able to dissolve in an aqueous medium due to the presence of polar bonds.4The molecule increases fluidity of membranes as it contains a kink.A1 and 4B2 and 3 C3 and 4D1, 3 and 4 2018 / H2 / AJC PRELIM / P1 Q55Human hair is made up from bundles of a fibrous protein called keratin, which is similar to collagen.The diagram shows the folded structure of keratin polypeptide chain, which forms the basic unit of hair fibre structure. When hair is wet, it can lengthen temporarily due to the breaking of bonds in the folded keratin polypeptide chain. When it dries, the hair gradually returns to its original length.What are broken to produce this length of the keratin chain structure?Apeptide bondsBdisulfide bondsChydrophobic interactionsDhydrogen bonds

2018 / H2 / AJC PRELIM / P1 Q66The diagram shows the effect of increasing substrate concentration on the rate of an enzyme-catalysed reaction at different concentrations of an inhibitor of the enzyme. Which statements correctly explain the results of this investigation?1The inhibitor is a competitive inhibitor. 2The inhibitor is a non-competitive inhibitor. 3Adding 0.1% inhibitor lowers the effective enzyme concentration by altering enzyme tertiary structure, therefore the maximal rate of reaction cannot be restored at high substrate concentration.4Increasing inhibitor concentration results in the inhibitor being able to compete effectively with the substrate molecules to form more enzyme – inhibitor complexes, t