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

1. The total amount of purine nucleotides and pyrimidine nucleotides is not always equal

2. There are two strands which run parallel in 5'$\to$3' direction

3. The proportion of adenine in relation to thymine varies with the organism

4. There are two strands which run antiparallel one in 5'$\to$3' direction and other in 3'$\to$5' direction 

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

1. 3.4$°$

2. 34$°$

3. 3.6$°$

4. 36$°$

The bond between the phosphate and hydroxyl group of sugar  is an

(1)ether bond

(2)ester bond

(3)glycosidic bond

(4)amide bond

How many phosphodiester bonds are present in 5’ATTTTTGG 3’ sequence of nucleotides

(1)7

(2)9

(3)8

(4)6

The DNA exists as _________helix which runs ________

(1)double, parallel

(2)double, antiparallel

(3)single, perpendicular

(4)single, parallel

The backbone of the DNA is formed by

(1)sugar, phosphate, sugar chain

(2)sugar, phosphate, nitrogenous base chain

(3)Phosphate, sugar, phosphate chain

(4)Both A and B

Which of the following is the pitch of B-DNA

(1)34Angstrom

(2)34 nanometre

(3)34 picometre

(4)34 femtometre

The nitrogenous bases of the two  strands of DNA are joined by 

1. Phosphodiester bond

2. Hydrogen bond

3. Glycosidic bond

4. Peotide bond