Chapter 9

Enzymes which catalyse the inter-conversion of optical, geometric or positional isomers belongs to the class of class (a) Isomerase (b) Transferase (c) Hydrolase (d) Ligase

Enzymes catalysing the linking together of two compounds, for example enzymes which catalyse the joining of \(\mathrm{C}-\mathrm{O}, \mathrm{C}-\mathrm{S}, \mathrm{C}-\mathrm{N}, \mathrm{P}-\mathrm{O}\), etc., bonds, belongs to the class of (a) Isomerases (b) Transferases (c) Hydrolases (d) Ligases

The suffix '-' added to substrate for naming the enzyme is (a) -ase (b) -in (c) - zyme (d) -ose

When Apoenzyme is separated from its metal component, its activity is (a) Decreased (b) Increased (c) Lost (d) Remains unaffected

Cofactors are (a) Prosthetic groups (b) Co-enzymes (c) Metallic ions (d) All of these

Which of the following combinations is correct? (a) Metal ions loosely attached with Apoenzyme-Activators. (b) Non-protein organic part attached tightly to the Apoenzyme-Prosthetic group. (c) Non-protein organic part attached loosely to the Apoenzyme-Coenzyme. (d) All of these

Which one of the following is not a cofactor? (a) Coenzyme (b) Metal ions (c) Prosthetic group (d) Apoenzyme

Haem is a prosthetic group of enzyme (a) Peroxidase (b) Catalase (c) Both (a) and (b) (d) None of these

\(\mathrm{Zn}\) is an activator of \(\quad\) enzyme. (a) Carbonic anhydrase (b) Carboxypeptidase (c) Carboxylases (d) All of these

Which of the following statement is correct? (1) Catalytic activity is lost when the co-factor is removed from the enzyme. (2) Coenzyme nicotinamide adenine dinucleotide (NAD) and NADP contains the vitamin niacin. (3) Biomacromolecules have a hierarchy of structures such as primary, secondary, tertiary and quaternary. (4) Enzymes lower the activation energy of reactions and enhance greatly the rate of the reactions. (5) Nucleic acids carry hereditary information and are passed on from parental generation to progeny. (a) 1 and 5 only (b) 2 and 3 only (c) 2 and 5 only (d) All of these

Assertion: Arachidonic acid is an unsaturated fatty acid. Reason: There are one or more double bonds which are present between the carbon atoms in unsaturated fatty acids.

Assertion: Coenzyme is a nonprotein group without which enzymes are inactive or incomplete. Reason: Coenzymes not only provide a point of attachment for the chemical group being transformed but also influence the properties of the group.

Assertion: Activity of an enzyme is \(\mathrm{pH}\) dependent. Reason: Change in \(\mathrm{pH}\), affects the solubility of the enzyme in water.

Assertion: Enzymes are proteins which catalyse the biochemical reactions. Reason: The enzymes itself is unchanged in the reaction, its presence allows the reaction to take place.

Assertion: Simple carbohydrates having free aldose or ketose group are called reducing sugars. Reason: They can reduce cupric ion to cuprous state.

Assertion: Protein amino acids possess an amino group attached to a carbon ( \(\alpha\) amino acid). Reason: Proline and hydroxyproline have NH (imino group) so they are imino acids.

Assertion: Protein is a heteropolymer. Reason: Protein is made up of amino acid.

Assertion: Watson-Crick model of DNA is the secondary structure of DNA. Reason: It contains covalent as well as hydrogen bond.

Assertion: The total number of amino acids involved in protein synthesis in plants is 20 . Reason: Only 20 amino acids have been discovered so far.

Assertion: In human body 'collagen' is the most abundant protein. Reason: Scleroproteins occurs in hard parts of animals body for providing support and protection.

Assertion: Living state is a non-equilibrium steady state to be able to perform work. Reason: System at equilibrium cannot perform work.

Assertion: ATP is energy currency of cell. Reason: ATP is formed in catabolic pathway.

Assertion: There are two hydrogen bond exist between A\&T. Reason: There are three hydrogen bond exist between G\&C.

Assertion: The distance between adjacent base pair in B- DNA is \(3.4 \mathrm{~A}^{\circ}\). Reason: One full turn of helical strand of B-DNA contain 10 bp and the length of this pitch is \(34 \mathrm{~A}^{\circ}\).

Assertion: Tertiary structure is necessary for the many biological activities of proteins. Reason: Tertiary structure in 3 -dimentional view of protein.

Assertion: DNA is called deoxyribonucleic acid. Reason: DNA is nucleic acid containing dcoxyribose sugar.

Assertion: Starch forms complex with \(\mathrm{I}_{2}\) Reason: Starch forms secondary helical structure.

Assertion: Cellulose is homo polymer. Reason: Cellulose formed of only one type of monosaccharide viz. glucose

Assertion: Co-factor play sepical role in the catalytic activity of enzyme. Reason: Catalytic activity is lost when co-factor is removed.

Assertion: DNA and RNA consists of nucleotides only Reason: Nucleotides are monomer of Nucleic acid

Assertion: Starch with \(\mathrm{I}_{2}\) gives blue colour because of starch \(\mathrm{I}_{2}\) complex. Reason: Starch Can hold \(\mathrm{I}_{2}\) in their helical portion

Assertion: Cellulose doesn'\operatorname{tg} i v e ~ c o l o u r ~ w i t h ~ \(\mathrm{I}_{2}\) Reason: Cellulose doesn't contain helix which can hold \(\mathrm{I}_{2}\)

Assertion: In polysaccharide chain the right end is reducing Reason: The right end contain free anomeric -OH group.

Assertion: Chitin is homopolymer. Reason: Chitin is made up of only one type of monomer i.e. N-acetylglucosamine.

Assertion: The first amino acid in primary structure protein is called as N-terminal amino acid. Reason: \(\mathrm{NH}_{2}\) group of first amino acid is free, not bound to form peptide bond.

Assertion: Oil containing PUFA are good for health. Reason: They reduce blood cholesterol level. Thus, decreases chance of heart diseases.

Assertion: A B-DNA structure proposed by Watson and Crick is secondary structure. Reason: B- DNA contains hydrogen bond in addition to covalent bond.

Assertion: Conversion of glucose to lactic acid in our skeletal muscle is catabolic pathways. Reason: In this metabolic pathway complex structure is degraded to simpler one.

Assertion: Enzymes isolated from thermophilic organisms are thermally stable. Reason: They retain their catalytic power even at higher temperature.

Assertion: Enzyme increases the rate of biochemical reactions. Reason: Enzymes lower down the energy of activation.