The unequivocal proof that DNA is the genetic material was provided by :

(1) Avery, Macleod and McCarty

(2) Hershey and Chase

(3) Meselson and Stahl

(4) Watson and Crick

Which of the following is not a feature of the double helix model of DNA ?

(1) The two chains have anti-parallel polarity

(2) A purine always comes opposite to a pyrimidine

(3) The pitch of the DNA is 3.4 nm

(4) The two chains are coiled in a left handed fashion

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

Identify the incorrectly matched pair:

The amino acid acceptor arm of the tRNA is at its:

(1) DHU loop

(2) TψC loop

(3) 5' end

(4) 3' end

Which of the following codons has a dual role in the genetic code?

(1) AUG

(2) GUG

(3) CUG

(4) UUG

What is the major difference between the lagging and leading strands during DNA replication ?

1. On the leading strand, DNA synthesis occurs from 5' to 3', while DNA synthesis occurs from 3' to 5' on the lagging strand.

2. DNA polymerase is able to continuously add new nucleotides on the leading strand while it must keep 'starting over' on the lagging strand.

3. The lagging strand requires only a single primer while the leading strand requires many.

4. Helicase opens the leading stran at a faster rate than the lagging strand.

The inducer of lac operon is :

1. Beta galactosidase

2. Galactose

3. Lactose

4. Glucose

regulatory domains of most activators interact with

1. the transcription factor complex

2. RNA polymerase

3. repressors

4. the DNA binding domain