According to Erwin Chargaff, for a double stranded DNA

(1) The ratios between Adenine and Thymine, and, Guanine and Cytosine are constant and equals one. 

(2) The ratios between Adenine and Thymine, and, Guanine and Cytosine are constant but is not equal to one. 

(3) The ratios between Adenine and Guanine, and,Thymine, and Cytosine are constant and equals one. 

(4) The ratios between Adenine and Guanine, and, Thymine and, Cytosine are constant but is not equal to one. 

To form a nucleoside, a nitrogenous base is linked to a pentose sugar:

1. Through a P-Glycosidic linkage at carbon atom number 1

2. Through a P-Glycosidic linkage at carbon atom number 5

3. Through a N-Glycosidic linkage at carbon atom number 1

4. Through a N-Glycosidic linkage at carbon atom number 5

Genetic information in a DNA molecule is coded in the:

1. Sequence of nucleotides

2. Base pairings 

3. Proportion of each base present

4. The turning pattern of the helix

DNA fragments are

1. positively charged

2. negatively charged

3. neutral

4. either positively or negatively charged depending on their size

Which one of the following is not applicable to RNA ?

1. Complementary base pairing

2. 5' phosphoryl and 3' hydroxyl ends

3. Heterocyclic nitrogenous bases

4. Chargaff's rule

Identify the correct order of organisation of genetic material from largest to smallest.

(1) Chromosome, gene, genome, nucleotide

(2) Genome, chromosome, nucleotide, gene

(3) Genome, chromosome, gene, nucleotide

(4) Chromosome, genome, nucleotide, gene

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/34%, A/24.5%, T/24.5%

2. G/17%, A/16.5%, T/32.5%

3. G/17%, A/33%, T/33%

4. G/8.5%, A/50%, T/24.5%

In a 3.2 Kbp long piece of DNA, 820 adenine bases were found. What would be the number of cytosine bases?

(1) 780

(2) 1560

(3) 740

(4) 1480

Suppose, evolution on earth had occurred in such a way that there are 96 amino acids instead of 20. DNA has 12 different types of bases and DNA synthesis occurs in the same way as today. The minimum number of bases per DNA codon would be

1. 12

2. 8

3. 2

4. 3

If the total amount of adenine and thymine in a double-stranded DNA is 45%, the amount of guanine in this DNA will be

1. 22.5%

2. 27.5%

3. 45%

4. 55%