Given below is the diagrammatic representation of one of the categories of small molecular weight organic compounds in the living tissues. Identify the category shown and the one blank component "X" in it.

   Category                                Component

1. Cholesterol                                Guanine
2. Amino acid                                 NH₂
3. l Nucleotide                               Adenine
4. Nucleoside                                 Uracil

Which one of the following is a non-reducing carbohydrate?

Select the option which is not correct with respect to enzyme action:
1. Substrate binds with enzyme at its active site.
2. Addition of a lot of succinate does not reverse the inhibition of succinic dehydrogenase by malonate.
3. A non-competitive inhibitor binds the enzyme at a site distinct from that which binds the substrate.
4. Malonate is a competitive inhibitor of succinic dehydrogenase.

Which one of the following statements is incorrect?
1. In competitive inhibition, the inhibitor molecule is not chemically changed by the enzyme.
2. The competitive inhibitor does not affect the rate of breakdown of the enzyme-substrate complex.
3. The presence of the competitive inhibitor decreases the Km of the enzyme for the substrate.
4. A competitive inhibitor reacts reversibly with the enzyme to form an enzyme-inhibitor complex.

In sea urchin DNA, which is double stranded, 17% of the bases were shown to be cytosine. The percentages of the other three bases expected to be present in this DNA are :
1. G 17%, A 16.5%,T32.5%
2. G 17%, A 33%,T 33%
3. G8.5%,A50%, T24.5%
4. G 34%,A 24.5%,T 24.5%

Which one of the following is not applicable to RNA?
1. 5’ phosphoryl and 3’ hydroxyl ends
2. Heterocyclic nitrogenous bases
3. Chargaff’s rule
4. Complementary base pairing

Which of the following biomolecules does have phosphodiester bond ?
1. Monosaccharides in a polysaccharide
2. Amino acids in a polypeptide
3. Nucleotides in a Nucleic acid
4. Fatty acids in a diglyceride

A typical fat molecule is made up of :
1. Three glycerol and three fatty acid molecules
2. Three glycerol molecules and one fatty acid molecule
3. One glycerol and three fatty acid molecules
4. One glycerol and one fatty acid molecule

Which one of the following statements is wrong?
1. Glycine is a sulphur containing amino acid.
2. Sucrose is a disaccharide.
3. Cellulose is a polysaccharide.
4. Uracil is a pyrimidine.

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