DNA Replication Review

Why does DNA replicate?

• To create a duplicate copy in case the original gets damaged

• New cells will have a copy of the DNA

• To create a new copy to replace the damaged original

What does DNA stand for?

• Deoxyribonucleic acid

• Denitrogenous acid

• Deribonucleic acid

• Diribonucleic acid

Cytosine bonds with ____

• Adenine

• Thymine

• Guanine

• Uracil

Which enzyme is responsible for 'gluing' Okazaki fragments together?

• DNA polymerase

• Primase

• Ligase

• Helicase

Answer explanation

Ligase 'glues' the Okazaki fragments together.

The enzyme that attaches the complimentary base pairs to the original strand of DNA is called...

• helicase

• DNA polymerase

• replicase

• synthase

Answer explanation

DNA Polymerase is the builder!

Why do we get Okazaki fragments?

• Because DNA polymerase can only be built in a 5' - 3' direction

• Because DNA polymerase can only be built in a 3' - 5' direction

• Because is it more efficient to build DNA in fragments

• Because the enzyme primase is limited

Answer explanation

So as the DNA polymerase can only build in the 5' - 3' direction, the lagging strand can only build fragments at a time and not a continuous strand.

What which enzyme is represented by B?

• Ligase

• Primase

• DNA Polymerase

• Helicase

Answer explanation

B is DNA polymerase because it is building the DNA on both strands.

What which enzyme is represented by A?

• Ligase

• Primase

• DNA Polymerase

• Helicase

Answer explanation

A is helicase because it is breaking the hydrogen bonds and 'unzipping' the DNA.

Which is the LAGGING strand D or E?

• D

• E

Answer explanation

The lagging strand builds in a 5' - 3' direction AWAY from the replication fork.

Which is the LEADING strand D or C?

• D

• C

Answer explanation

The leading strand builds in a 5' - 3' direction TOWARDS the replication fork.