after the dna strands are separated, which of the following is the next step of DNA replication in the S phase of the cell cycle?
Action of helicase
formantion of RNa primer
breaking go hydrogen bonds
joining of nucleotides
i think either B or D
The correct next step of DNA replication in the S phase of the cell cycle after the DNA strands are separated is the formation of an RNA primer. The RNA primer is needed to initiate the synthesis of a new DNA strand. This primer is then used by DNA polymerase to add nucleotides and extend the new DNA strand. So the correct answer is formation of RNA primer (option B).
To determine the correct next step of DNA replication in the S phase of the cell cycle, let's analyze each option:
A. Action of helicase: Helicase is responsible for unwinding the double-stranded DNA, separating the two strands. While helicase is involved in DNA replication, it is not the immediate next step after the strands are separated.
B. Formation of RNA primer: This step is correct. After the DNA strands are separated, the enzyme called primase creates a short RNA primer, which serves as the starting point for the synthesis of new DNA strands.
C. Breaking of hydrogen bonds: Hydrogen bonds hold the two strands of DNA together, and they must be broken for replication to occur. However, the question is asking for the next step after the strands are separated, so breaking hydrogen bonds is not the immediate next step.
D. Joining of nucleotides: This step occurs after the formation of the RNA primer. During DNA replication, nucleotides are added to the growing DNA strand, and an enzyme called DNA polymerase joins them together. However, this step occurs after the RNA primer is formed.
Based on the above analysis, the correct answer is option B: formation of RNA primer.