AP BIOLOGY

LABORATORY REVIEW

MOLECULAR BIOLOGY

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which are necessary to make DNA replication semi-conservative?I. Separation of the strands by RNA polymeraseII. Complementary base pairingIII. Use of a pre-existing strand as a template
A
I and II only
B
I and III only
C
II and III only
D
I, II and III
Explanation: 

Detailed explanation-1: -For semiconservative replication to occur, the DNA double-helix needs to be separated so the new template strand can be bound to the complementary base pairs. Topoisomerase is the enzyme that aids in the unzipping and recombination of the double-helix.

Detailed explanation-2: -Replication is initiated by a virus-encoded protein (called T antigen) that binds to the origin and also acts as a helicase. A single-stranded DNA-binding protein is required to stabilize the unwound template, and the DNA polymerase -primase complex then initiates DNA synthesis.

Detailed explanation-3: -DNA replication is semi-conservative because each helix that is created contains one strand from the helix from which it was copied. The replication of one helix results in two daughter helices each of which contains one of the original parental helical strands.

There is 1 question to complete.