Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Prion disease considered to be infectious Reason R : The misfolded protein induce misfolding of normal proteins In the light of the above statements, choose the correct answer from the options given below

• A. Both A and R are true and R is the correct explanation of A
• B. Both A and R are true but R is NOT the correct explanation of A
• C. A is true but R is false
• D. A is false but R is true

Hint:

Prions:
• Infectious proteins
• No DNA or RNA
• Cause protein misfolding

Answer 1

The Correct Option is A

Concept: Prions are infectious protein particles that do not contain nucleic acids. They are abnormal misfolded proteins capable of converting normal proteins into abnormal forms. This property makes prion diseases infectious and progressive.

Step 1: Understand Assertion A carefully. Assertion states: \[ \text{Prion disease considered to be infectious} \] This statement is correct because:
• Prions can spread from one protein molecule to another.
• They can transmit disease between cells and organisms. Examples:
• Mad cow disease
• Creutzfeldt-Jakob disease
• Scrapie Thus Assertion A is true.

Step 2: Understand Reason R carefully. Reason states: \[ \text{Misfolded proteins induce misfolding of normal proteins} \] This is scientifically correct. Prions act by:
• Altering normal protein conformation
• Converting healthy proteins into pathogenic misfolded proteins This chain reaction causes:
• Accumulation of abnormal proteins
• Degeneration of nervous tissue Hence Reason R is true.

Step 3: Check whether Reason explains Assertion. Reason directly explains why prion diseases are infectious. Because:
• Misfolded proteins themselves spread abnormal folding. Thus infectious nature of prions depends on: \[ \boxed{ \text{Protein-induced protein misfolding} } \] Therefore Reason correctly explains Assertion.

Step 4: Select correct option. Both statements are true and Reason correctly explains Assertion. Thus correct answer is: \[ \boxed{(1)} \] Final Conclusion: Prions are infectious because abnormal proteins convert normal proteins into misfolded pathogenic forms. Hence: \[ \boxed{ \text{Both A and R are true and R correctly explains A} } \]