What is the first step in eukaryotic DNA replication?

• A. Binding of DNA polymerase to the DNA strand
• B. Joining of Okazaki fragments by ligase
• C. Synthesis of RNA primers by primase
• D. Unwinding of the DNA helix by helicase

Answer: (D)

Verified step by step guidance

1. Understand that DNA replication is a complex process involving multiple steps and enzymes.
2. Recognize that the first step in eukaryotic DNA replication is the unwinding of the DNA double helix.
3. Identify the enzyme responsible for this unwinding process, which is helicase.
4. Helicase breaks the hydrogen bonds between the base pairs, separating the two strands of DNA to create a replication fork.
5. This unwinding is essential to allow other enzymes, such as primase and DNA polymerase, to access the single-stranded DNA for replication.