Question

Which of the following is a correct statement about the process of DNA replication?

• A.
  DNA synthesis takes place mainly by DNA–polymerase I in E. coli
• B. Gap filling after the removal of primer is done by DNA–polymerase III
• C. SSB proteins bind to the DNA strand in which the leading strand of replicating DNA is synthesized
• D.
  Direction of DNA synthesis in the lagging strand is 5’ 3’ direction

Answer 1

The correct option is A

DNA synthesis takes place mainly by DNA–polymerase I in E. coli
DNA is made up of a double helix of two complementary strands. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart.
DNA synthesis occur by the enzyme DNA polymerase, and gap is filled by the enzyme DNA ligase.
Direction of synthesis of leading strand is 5' to 3' and direction of synthesis of lagging strand is 3' to 5' direction.
Leading-strand replication occurs efficiently in the complete absence of SSB proteins.
So, the correct answer is 'DNA synthesis takes place mainly by DNA–polymerase I in E. coli'.