Question

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

• A. The DNA dependent DNA polymeras catalyses polymerization in one direction that is 3'\(→\)5'.
• B. The DNA dependent RNA polymeras catalyses polymerization in one direction that is 5'\(→\)3'.
• C. The DNA dependent DNA polymeras catalyses polymerization in 5'\(→\)3' as well as 3'\(→\)5' direction.
• D. The DNA dependent DNA polymeras catalyses polymerization in 5'\(→\)3' direction.

Answer 1

The Correct Option is D

Let's analyze each statement:

Option 1: The DNA-dependent DNA polymerase catalyses polymerization in one direction, that is, 3'→5'.

This is incorrect. DNA polymerase always adds nucleotides to the 3' end of the growing DNA strand, meaning it synthesizes in the 5'→3' direction, not 3'→5'.

Option 2: DNA-dependent RNA polymerase catalyses polymerization in one direction, that is 5'→3'.

This is incorrect. DNA-dependent RNA polymerase is involved in transcription (RNA synthesis), not DNA replication. DNA-dependent DNA polymerase is used for DNA replication. Also, while RNA polymerase works 5'->3', this is talking about DNA replication, not RNA transcription.

Option 3: The DNA-dependent DNA polymerase catalyses polymerization in 5'→3' as well as 3'→5' direction.

This is incorrect. DNA polymerase can only synthesize DNA in the 5'→3' direction. It cannot add nucleotides to the 5' end of a growing strand.

Option 4: The DNA-dependent DNA polymerase catalyses polymerization in the 5'→3' direction.

This is correct. DNA-dependent DNA polymerase is the enzyme responsible for DNA replication in E. coli. It adds nucleotides to the 3' end of the growing DNA strand, synthesizing in the 5'→3' direction.

Therefore, the correct statement is that DNA-dependent DNA polymerase catalyzes polymerization in the 5'→3' direction.