DNA Replication

What is the first step in DNA replication?

To unwind the double helix by breaking the hydrogen bonds using the enzyme helicase.

What is the role of helicase in DNA replication?

Helicase unwinds the double helix into two strands.

What do the exposed DNA strands form during replication?

A Y-shaped replication fork.

Where does DNA replication begin?

At specific sites called origins of replication.

What is the function of DNA topoisomerases during replication?

They cut and rejoin the helix to prevent tangling.

Which enzyme adds nucleotides to the growing DNA strand?

DNA polymerase.

What is the orientation in which nucleotides can be added to a growing DNA strand?

In the 5′ to 3′ direction.

What is the role of RNA primase in DNA replication?

It adds a short strand of RNA nucleotides called an RNA primer.

What are Okazaki fragments?

Pieces of nucleotides that make up the lagging strand during DNA replication.

What enzyme links Okazaki fragments together?

DNA ligase.

What is the significance of telomeres?

They are the bits of unimportant DNA at the ends of a molecule.

What is meant by semiconservative replication?

Each new DNA molecule has half of the original molecule.

What are the main enzymes involved in DNA replication?

DNA helicase, DNA polymerase, DNA ligase, topoisomerase, and RNA primase.

What happens to the RNA primer after DNA replication?

It is degraded by enzymes and replaced with DNA.

How is the leading strand different from the lagging strand?

The leading strand is made continuously, while the lagging strand is made in pieces (Okazaki fragments).