Which of the following statements is incorrect?

Options

A. prions consist of abnormally folded proteins
B. Viroids lack a protein coat
C. Viruses are obligate parasites
D. Infective constituent in viruses is the protein coat

Answer

To determine which statement is incorrect, we need to analyze each statement provided in the question.

1. **Statement 1**: "Prions consist of abnormally folded proteins."
- **Analysis**: This statement is correct. Prions are indeed misfolded proteins that can induce other proteins to also misfold, leading to diseases.

2. **Statement 2**: "Viruses are present in the brain. Protein is not present in the brain. Protein is absent in the brain."
- **Analysis**: This statement is incorrect. Proteins are present in the brain; in fact, the brain is composed of various proteins that are essential for its function. While viruses can be present in the brain, the claim that proteins are absent is false.

3. **Statement 3**: "Viruses are obligate parasites."
- **Analysis**: This statement is correct. Viruses cannot replicate or carry out metabolic processes without a host cell, making them obligate parasites.

4. **Statement 4**: "Infective Constituent in Viruses is the protein coat."
- **Analysis**: This statement is misleading. While some viruses have a protein coat (capsid), the infective part of a virus is primarily its genetic material (either DNA or RNA). The protein coat protects the genetic material but is not the infective constituent itself.

Based on the analysis, the incorrect statement is:

**Answer**: "Viruses are present in the brain. Protein is not present in the brain. Protein is absent in the brain."