Difference between virus and viroid is

Options

A. absence of protein coat in viroid, but present in virus
B. presence of low molecular weight RNA in virus, but absent in viroid,
C. Both (a) and (b)
D. None of the above

Explanation

To understand the differences between viruses and viroids, we can break down the characteristics of each step by step:

### Step 1: Definition of Virus
- **Viruses** are microscopic infectious agents that can only replicate inside the living cells of an organism. They consist of genetic material (either DNA or RNA) surrounded by a protein coat known as a capsid.

### Step 2: Definition of Viroid
- **Viroids** are much simpler infectious agents. They are composed solely of a short strand of circular RNA and do not have a protein coat.

### Step 3: Genetic Material
- **Viruses** can contain either DNA or RNA as their genetic material.
- **Viroids** only contain RNA as their genetic material.

### Step 4: Protein Coat
- **Viruses** have a protein coat (capsid) that protects their genetic material.
- **Viroids** do not have a protein coat at all.

### Step 5: Examples
- An example of a virus is the Hepatitis B virus, which has a protein coat and can carry viroids.
- An example of a viroid is the Hepatitis D viroid, which is carried within the capsid of the Hepatitis B virus.

### Conclusion
The primary differences between viruses and viroids can be summarized as follows:
1. **Presence of Protein Coat**: Viruses have a protein coat, while viroids do not.
2. **Type of Genetic Material**: Viruses can have either DNA or RNA, whereas viroids only have RNA.

### Final Answer
The correct difference between a virus and a viroid is that **viruses have a protein coat, while viroids do not have any protein coat**.

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