What is the function of single-strand binding proteins during replication?

What is the function of single-strand binding proteins during replication?

• A. They unwind the double helix.
• B. They stabilize exposed single-stranded DNA to prevent secondary structures and keep it accessible for polymerases.
• C. They seal nicks in the backbone.
• D. They synthesize primers.

Answer: (B)

During DNA replication, the DNA strands are unwound to expose single-stranded templates. Single-strand binding proteins quickly bind to these exposed templates to stabilize them, preventing the strands from snapping back together and from forming secondary structures like hairpins. This stabilization keeps the single-stranded DNA accessible for DNA polymerases to copy the sequence accurately. They also help protect the vulnerable ssDNA from nucleases until synthesis is finished. This function is distinct from helicase, which unwinds the helix; primase, which lays down primers to start synthesis; and ligase, which seals nicks in the backbone.

During DNA replication, the DNA strands are unwound to expose single-stranded templates. Single-strand binding proteins quickly bind to these exposed templates to stabilize them, preventing the strands from snapping back together and from forming secondary structures like hairpins. This stabilization keeps the single-stranded DNA accessible for DNA polymerases to copy the sequence accurately. They also help protect the vulnerable ssDNA from nucleases until synthesis is finished. This function is distinct from helicase, which unwinds the helix; primase, which lays down primers to start synthesis; and ligase, which seals nicks in the backbone.