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

• A. They synthesize the RNA primer needed for DNA polymerase.
• B. They unwind the DNA double helix.
• C. They join Okazaki fragments on the lagging strand.
• D. They prevent the re-annealing of the DNA strands.

Answer: (D)

Verified step by step guidance

1. During DNA replication, the double-stranded DNA needs to be separated into single strands to serve as templates for the synthesis of new DNA strands.
2. Once the DNA double helix is unwound by helicase, the single-stranded DNA is prone to re-annealing or forming secondary structures, which can interfere with replication.
3. Single-strand binding proteins (SSBs) bind to the separated single strands of DNA to stabilize them and prevent them from re-annealing or forming secondary structures.
4. By binding to the single-stranded DNA, SSBs ensure that the strands remain open and accessible for the DNA polymerase to synthesize new complementary strands.
5. This stabilization is crucial for efficient and accurate DNA replication, allowing the replication machinery to function properly without interruptions.