Arrange the various proteins involved DNA replication in the correct sequence they are used.
(i) single strand binding proteins
(ii) Topoisomerase
(iii) Phosphorylase
(iv) DNA ligase
(v) Helicase

Options

A. `(iii)rarr (v)rarr (i)rarr (ii) rarr(iv)`
B. `(i)rarr (ii)rarr (v)rarr (iii) rarr(iv)`
C. `(v)rarr (i)rarr (iv)rarr (ii) rarr(iii)`
D. `(v)rarr (ii)rarr (i)rarr (iii) rarr(iv)`

Answer

To arrange the various proteins involved in DNA replication in the correct sequence, we will analyze the function of each protein mentioned in the question.

1. **Phosphorylase**: This enzyme is responsible for adding phosphate groups to nucleotides, which is an essential step in the formation of DNA strands. However, it is not directly involved in the initial steps of DNA replication.

2. **Helicase**: This enzyme unwinds the double-stranded DNA, separating it into two single strands. This is a crucial step that allows the replication machinery to access the DNA template.

3. **Single Strand Binding Proteins (SSBPs)**: Once the DNA is unwound by helicase, SSBPs bind to the single-stranded DNA to prevent it from re-annealing or forming secondary structures. This ensures that the template strands remain accessible for replication.

4. **Topoisomerase**: As the DNA unwinds, it can become overwound ahead of the replication fork. Topoisomerase alleviates this tension by cutting the DNA, allowing it to unwind, and then rejoining it.

5. **DNA Ligase**: After the new DNA strands are synthesized, there may be gaps or Okazaki fragments on the lagging strand. DNA ligase is responsible for joining these fragments together to form a continuous DNA strand.

Now, putting this information together, the correct sequence of proteins involved in DNA replication is:

1. **Helicase** (unwinds the DNA)
2. **Single Strand Binding Proteins** (stabilize the unwound DNA)
3. **Topoisomerase** (relieves tension in the DNA)
4. **DNA Ligase** (joins Okazaki fragments)

**Final Sequence**:
1. Helicase
2. Single Strand Binding Proteins
3. Topoisomerase
4. DNA Ligase

**Note**: Phosphorylase is not directly involved in the sequence of actions during DNA replication, so it is not included in the final sequence.