Match each item in COLUMN I with one in COLUMN II and select your answer from the codes given:

COLUMN I	COLUMN II
SCIENTIST	CONTRIBUTION
Francis Crick	a. Breaking the genetic code
Nirenberg	b. Established Caenorhabditis elegans as a model genetics  study organism
Benzer	c. Central dogma of molecular biology
Brenner	d. Bacteriophase genetics

	A	B	C	D
1.	c	a	d	b
2.	c	a	b	d
3.	a	b	c	d
4.	a	c	d	b

Which enzyme polymerizes RNA with defined sequences in a template independent manner?

1. Peptidyl transferase

2. RNA polymerase

3. Reverse transcriptase

4. Polynucleotide phosphorylase

The process of RNA splicing shows the dominance of :

1. DNA world

2. RNA world

3. Protein world

4. Microbial world

In RNA splicing :

1. Exons are removed and introns are joined together

2. Introns are removed and exons are joined together

3. Cistrons are removed and introns are joined together

4. Introns are removed and Cistrons are joined together

The core RNA polymerase is capable of catalyzing which steps of transcription ?

1. Initiation only

2. Elongation only

3. Termination only

4. All of these

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. One 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?

\(1.\ {}^{35}S\)

\(2.\   {}^{15} N\)

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

\(4.\   N o n e\)