DNA Replication

According to the central dogma, which of the following represents the flow of genetic information in cells?

• protein to DNA to RNA

• DNA to RNA to protein

• RNA to DNA to protein

• DNA to protein to RNA

Which of the following is the enzyme that replaces the RNA nucleotides in a primer with DNA nucleotides?

• DNA polymerase III

• DNA polymerase I

• primase

• helicase

In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5’ to 3’ direction?

• DNA polymerase III

• DNA polymerase I

• primase

• helicase

A new DNA strand elongates only in the 5’ to 3’ direction because _____.

• DNA polymerase begins adding nucleotides at the 5’ end of the template

• The polarity of the DNA molecule prevents addition of nucleotides at the 3’ end

• Replication must progress toward the replication fork

• DNA polymerase can add nucleotides only to the free 3’ end

What is the function of topoisomerase?

• relieving strain in the DNA ahead of the replication fork

• elongating new DNA at a replication fork by adding nucleotides to the existing chain

• unwinding of the double helix

• stabilizing single-stranded DNA at the replication fork

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

• It synthesises RNA nucleotides to make a primer

• It joins Okazaki fragments together

• It unwinds the parental double helix

• It stabilizes the unwound parental DNA

The enzyme that carry out the above function is

• Primase

• Topoisomerase

• DNA Polymerase I

• DNA Polymerase III

Which of the following unwind the double helix strand of DNA during DNA replication?

• DNA helicase

• Topoisomerase

• DNA Polymerase I

• DNA Polymerase III

Which of the following relieves overwinding strain ahead of replication forks by breaking, swivelling, and re-joining DNA strands?

• DNA helicase

• Topoisomerase

• DNA Polymerase I

• DNA Polymerase III

Which of the following joined the Okazaki fragments together?

• DNA helicase

• Topoisomerase

• DNA ligase

• DNA Polymerase III