Question

As DNA replication continues and the replication bubble expands, the parental double helix is unwound and separated into its two component strands. This unwinding and separating of the DNA requires three different types of proteins: helicase, topoisomerase, and single-strand binding proteins. Sort the phrases into the appropriate bins depending on which protein they describe.

a. Bind at replication fork
b. bind after replication fork
c. prevent H-bond between bases
d. Break covalent bond in DNA banckbone

Answer 1

A. Helicases

B. Single strand binding proteins

C. Single strand binding protein

D. Topoisomerases

Step-by-step explanation:

The helicases bind on the replication fork aiding in the unwounding of the DNA helix to allow for replication. The single strange binding proteins attach/bind to the separated single stranded DNA after the replication fork to prevent re-annealing of the single stranded DNA preventing Hydrogen bond formation that reanneals these two strands together. The topoisomerases are found just ahead of the replication fork preventing overwounding/ positive supercoils of the DNA. They do this by introducing breaks into the phosphate backbone of the DNA allowing them rotate forming negative supercoils and attaching the breaks once the DNA strand is relaxed.