Proteins that help to open up DNA helix in front of the replication fork in prokaryotes are

Options

A. topoisomerases
B. unwindases (helicases)
C. polymerase 1
D. exonucleases and endocuclease

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Structure**: DNA is a double helical structure composed of two strands that are held together by hydrogen bonds between complementary nucleotides.

2. **DNA Replication Process**: During DNA replication, the two strands of the DNA helix need to be separated to allow for the synthesis of new complementary strands. This process is essential for cell division and the production of identical daughter cells.

3. **Role of Proteins in DNA Unwinding**: To initiate the separation of the DNA strands, specific proteins are required to break the hydrogen bonds between the nucleotides. This unwinding of the DNA helix is crucial for the replication process.

4. **Identifying the Key Protein**: The primary protein responsible for unwinding the DNA helix at the replication fork in prokaryotes is called helicase. Helicase binds to the DNA and moves along the strand, breaking the hydrogen bonds and separating the two strands.

5. **Additional Proteins**: While helicase is the main protein that opens up the DNA helix, other proteins such as topoisomerase also play a role in relieving the tension that builds up ahead of the replication fork due to supercoiling.

6. **Conclusion**: The protein that helps to open up the DNA helix in front of the replication fork in prokaryotes is helicase, also known as unwindase.

**Final Answer**: The proteins that help to open up the DNA helix in front of the replication fork in prokaryotes are helicases (or unwindase).

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