In most prokaryotes the transcription unit is :

1. Mono-cistronic

2. Poly-cistronic

3. Multi-cistronic

4. Uni-cistronic

What defines the position and presence of coding and a template strand in the transcription unit ?

1. Structural gene

2. Ori

3. Terminator

4. Promoter

Which of the following is true for both transcription and DNA replication?

1. Principle of complementarity governs the processes

2. Only of the two strands act as template

3. Only a segment of both strands is involved 

4. Adenine base pairs with thymine

The DNA dependent DNA polymerases catalyze:

1. Only in 3'-5' direction

2. Only in 5'-3' direction

3. In both directions

4. In neither directions

Which non-radioactive isotope was used by Meselson and Stahl to label DNA in their experiment?

\(1.\ {}^{35}S\)

\(2.\   {}^{15} N\)

\(3.{}^{32} P\)

\(4.\   N o n e\)

Histones are :

1. Positively charged and basic proteins

2. Negatively charged and basic proteins

3. Positively charged and acidic proteins

4. Found in bacteria

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

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

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

1. AUG

2. GUG

3. CUG

4. UUG

The inducer of lac operon is :

1. Beta galactosidase

2. Galactose

3. Lactose

4. Glucose