Read the following five statements in context of a plasmid. (a) Its DNA is always double stranded. (b) Its DNA is naked and without histone proteins. (c) Its DNA can replicate independent of genomic DNA. (d) Both exons and introns are present in plasmid DNA. (e) Plasmid DNA can be either linear or circular. Which of the above given statements are incorrect?

Options

A. (a) and (e)
B. (c) and (e)
C. (a), (b) and (c)
D. (d) and (e)

Answer

To determine which statements about plasmids are incorrect, let's analyze each statement one by one:

1. **Statement (a): Its DNA is always double stranded.**
- Plasmids are indeed composed of double-stranded DNA. This statement is correct.

2. **Statement (b): Its DNA is naked and without histone proteins.**
- Plasmid DNA is not associated with histone proteins, which is characteristic of prokaryotic DNA. Therefore, this statement is also correct.

3. **Statement (c): Its DNA can replicate independent of genomic DNA.**
- Plasmids have the ability to replicate independently of the chromosomal DNA, which is a defining feature of plasmids. This statement is correct.

4. **Statement (d): Both exons and introns are present in plasmid DNA.**
- Plasmids do not contain introns; they typically consist of genes that are usually prokaryotic in nature, which do not have introns. This statement is incorrect.

5. **Statement (e): Plasmid DNA can be either linear or circular.**
- Plasmids are primarily known to be circular in structure. While there are some linear plasmids, the majority are circular, and the statement can be misleading. Therefore, this statement is also considered incorrect.

### Summary of Incorrect Statements:
- Statement (d) is incorrect because plasmids do not contain introns.
- Statement (e) is misleading because plasmids are predominantly circular, making it incorrect in the context of typical plasmid structure.

### Final Answer:
The incorrect statements are (d) and (e).