Question

3. Specifically describe what would occur in DNA replication if the following components were missing, be thoughtful and do not simply state that DNA replication would not occur. Differentiate between prokaryotic and eukaryotic replication when appropriate.

DNA ligase-

DNA polymerase-

Primer-

Primase-

Topoisomerase-

Helicase-

SSBP-

Sliding clamp/PCNA-

Telomerase-

Answer 1

DNA ligase: Okazaki fragments on the lagging strand cannot be joined together to form a continuous strand.

DNA polymerase: Polymerization of nucleotides to produce a DNA strand in 5'-3' direction does not occur.

Primer: Initiation of replication does not occur as DNA polymerase requires a free 3'-OH group for chain extension.

Primase: RNA primer cannot be synthesized to strat strand extension in the 5'-3' direction.

Topoisomerase: helicase cannot unwind the helix as supercoiling would lead to the breaking of DNA strands.

Helicase: DNA double helix cannot be unwound.

SSBP: The unwound DNA duplex would rewind to form the duplex again.

Sliding clamp/PCNA- Processivity of the polymerase would be reduced.

Telomerase: Chromosomal ends would be deleted in the new strand.