Which is wrong about viruses ?

Options

A. They have ability to synthesiz nucleic acids and proteins
B. Antibiotics have no effect on them
C. All are parasites
D. All of them have helical symmetry

Answer

To determine which statement about viruses is incorrect, let's analyze each option provided in the question:

1. **Viruses have the ability to synthesize nucleic acids and proteins.**
- This statement is **incorrect**. Viruses do not have the machinery to synthesize nucleic acids and proteins on their own. Instead, they rely on the host cell's machinery to replicate their genetic material and produce proteins.

2. **Antibiotics have no effect on them.**
- This statement is **correct**. Antibiotics are designed to target bacterial structures and functions, and they do not affect viruses, which lack cellular structures.

3. **All are parasites.**
- This statement is **correct**. Viruses are obligate intracellular parasites, meaning they can only replicate inside a host cell, deriving their resources from the host.

4. **All of them have helical symmetry.**
- This statement is **incorrect**. While some viruses do exhibit helical symmetry, not all viruses have this structure. Viruses can have various types of symmetry, including icosahedral and complex shapes.

Based on the analysis, the statement that is wrong about viruses is:

**Answer: "All of them have helical symmetry."**

### Step-by-Step Solution:
1. **Identify the statements about viruses.**
- Review each statement carefully to understand what they imply about viruses.

2. **Evaluate the first statement.**
- Check if viruses can synthesize nucleic acids and proteins. Conclude that they cannot do this independently.

3. **Evaluate the second statement.**
- Confirm that antibiotics do not work on viruses. This is true as antibiotics target bacterial cells.

4. **Evaluate the third statement.**
- Recognize that viruses are indeed parasites, as they rely on host cells for replication.

5. **Evaluate the fourth statement.**
- Investigate the symmetry of viruses. Acknowledge that while some have helical symmetry, others have different forms, making the statement misleading.

6. **Conclude which statement is incorrect.**
- Identify that the fourth statement is incorrect because it generalizes the symmetry of all viruses.