Ori sequence in plasmid refers to sequence

Options

A. for antibody resistance
B. from which replication will start in plasmid
C. for restriction site
D. (4) both (1) and (3)

Answer

### Step-by-Step Solution:

1. **Understanding Plasmids**:
- Plasmids are small, circular DNA molecules found in bacteria. They can replicate independently of chromosomal DNA.

2. **Defining Ori Sequence**:
- The Ori (origin of replication) sequence in a plasmid is the specific location where DNA replication begins. This is crucial for the plasmid to replicate itself within the bacterial cell.

3. **Function of Ori Sequence**:
- The Ori sequence allows the plasmid to initiate replication, which is essential for the plasmid to be passed on to daughter cells during cell division.

4. **Evaluating the Options**:
- The question presents options related to the Ori sequence, including whether it refers to a sequence for antibiotic resistance or a restriction site.
- The Ori sequence is specifically related to the initiation of replication, not directly to antibiotic resistance or restriction sites.

5. **Conclusion**:
- Based on the definition and function of the Ori sequence, the correct answer is that it refers to the sequence from which replication will start in the plasmid.

### Final Answer:
- The Ori sequence in a plasmid refers to the sequence from which replication will start.