Which of the following statement is correct regarding the process of replication in E.coli?

The correct answer is: The DNA dependent DNA polymerase catalyses polymerization in 5’ → 3’ direction

Step-by-step Explanation:

1. Understanding DNA Replication: Replication in Escherichia coli (a bacterium) is the process by which a cell duplicates its DNA before cell division. This process is highly accurate and is catalyzed by a group of enzymes.

2. Role of DNA-dependent DNA Polymerase: The main enzyme responsible for synthesizing new DNA strands in E. coli is DNA-dependent DNA polymerase. This enzyme uses a single-stranded DNA template to catalyze the polymerization of deoxyribonucleotides, creating a complementary new DNA strand.

3. Direction of Polymerization: DNA polymerases can only add free nucleotides to the 3'-OH group of an existing nucleotide strand. Consequently, the synthesis of a new DNA strand (polymerization) can only proceed in the 5’ → 3’ direction. The template strand is read in the 3’ → 5’ direction.

4. Evaluating the Options:
• "The DNA dependent DNA polymerase catalyses polymerization in one direction that is 3’ → 5’" is incorrect because polymerization occurs in the 5’ → 3’ direction.
• "The DNA dependent RNA polymerase..." is incorrect because replication is carried out primarily by DNA-dependent DNA polymerase, not RNA polymerase (which is mainly involved in transcription).
• "The DNA dependent DNA polymerase catalyses polymerization in 5’ → 3’ as well as 3’ → 5’ direction" is incorrect because DNA polymerase is strictly unidirectional and cannot catalyze polymerization in the 3’ → 5’ direction.
• "The DNA dependent DNA polymerase catalyses polymerization in 5’ → 3’ direction" is correct and reflects the biochemical constraint of the enzyme.