One turn of the helix in a B-form DNA is approximately

1. 0.34 nm

2. 3.4 nm

3. 2 nm

4. 20 nm

If DNA percentage of thymine is 20. What is the percentage of guanine?                         [2002]

1. 20%

2. 40%

3. 30%

4. 60%

Which is wrong about nucleic acids?                                 [1993]

1. DNA is single stranded in some viruses

2. RNA is double stranded occasionally

3. Length of one helix is 45 Å in B-DNA

4. One turn of Z-DNA has 12 bases

In the DNA molecule

Two free ribonucleotide units are interlinked with

1. Peptide bond

2. Covalent bond

3. Hydrogen bond

4. Phosphodiester bond

All of the following are nucleosides, except:

At each step of its ascent, the DNA strand turns:

1. 3.4$°$

2. 34$°$

3. 3.6$°$

4. 36$°$

Which of the following biomolecules does have a phosphodiester bond?

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       Guanin

2. Amino acid       NH₂

3. Nucleotide        Adenine

4. Nucleoside       Uracil

Which one of the following structural formulae of two organic compounds is correctly

identified with its related function?

1. A - triglyceride major - a source of energy

2. A - Lecithin - a component of cell membrane 

3. B - Adenine - forms nucleotides of the nucleic acids

4. Both 2. and 3.