Topic 6.2 (Module 32) DNA Replication

What is the purpose of DNA replication?

• The purpose of DNA replication is to ensure that each daughter cell receives an identical copy of the DNA.

• To create new proteins for the cell.

• To facilitate cell division without copying DNA.

• To repair damaged DNA strands.

Answer explanation

The purpose of DNA replication is to ensure that each daughter cell receives an identical copy of the DNA, which is crucial for maintaining genetic consistency during cell division.

What is the replication fork?

• The replication fork is a type of enzyme involved in DNA synthesis.

• The replication fork is the point where RNA is transcribed from DNA.

• The replication fork is a structure that only exists in prokaryotic cells.

• The replication fork is the Y-shaped region where the DNA is split into two strands for replication.

Answer explanation

The replication fork is the Y-shaped region where the DNA is split into two strands for replication. This structure is crucial for DNA synthesis, allowing the replication machinery to access the strands.

Match the following enzymes involved in DNA replication to their function.

• Relieves strain ahead of the replication fork

• Helicase

• Unwinds the DNA double helix

• Primase

• Joins Okazaki fragments

• Ligase

• Creates RNA primers for DNA synthesis

• Topoisomerase

• Synthesizes new DNA strands

• DNA Polymerase

What is the role of DNA polymerase during DNA replication?

• To unwind the double helix

• To add nucleotides to the 3' end of a growing DNA strand

• To join Okazaki fragments

• To synthesize RNA primers

Which strand is synthesized continuously during DNA replication?

• Leading strand

• Lagging strand

• Okazaki strand

• RNA primer strand

Why is the lagging strand synthesized discontinuously?

• Because it runs in the same direction as the replication fork

• Because DNA polymerase can synthesize in the 3' to 5' direction

• Because it runs in the opposite direction to the replication fork

• Because it does not require RNA primers

What are Okazaki fragments?

• Short segments of DNA on the leading strand

• Short segments of DNA on the lagging strand

• RNA primers used in DNA replication

• Enzymes that join DNA fragments

What enzyme is responsible for joining Okazaki fragments together?

• DNA polymerase

• Primase

• Helicase

• DNA ligase

Label the parts!

c

d

e

f

a

b

RNA primer

Helicase

Topoisomerase

Replication fork

Primase

single stranded binding protein

Which enzyme proofreads the DNA after replication to catch any mistakes?

• primase

• RNA polymerase

• DNA polymerase

• helicase

Answer explanation

DNA polymerase is the enzyme responsible for proofreading DNA during replication. It checks for errors and corrects them, ensuring the accuracy of the newly synthesized DNA strands.