Question

Statement I: Histones are rich in arginine and lysine. Thus, they are positively charged proteins at physiological pH.
Statement II: Histones are the most evolutionary conserved proteins known.
Choose the most appropriate answer from the following options:

• A. Statement I is correct and Statement II is incorrect
• B. Statement II is correct and Statement I is incorrect
• C. Statement I and Statement II both are correct
• D. Statement I and Statement II both are incorrect

Hint:

Histones: rich in arginine and lysine (basic amino acids).
Positively charged at physiological pH.
Highly conserved across species.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Histones are the proteins that package DNA into nucleosomes.
They have specific properties that enable their function.

Step 2: Key Formula or Approach:
No specific formula.
Need to understand the properties of histones.

Step 3: Detailed Explanation:
Statement I: Histones are rich in basic amino acids like arginine and lysine.
These amino acids are positively charged at physiological pH.
This positive charge helps histones bind to negatively charged DNA.
Thus, Statement I is correct.
Statement II: Histones are among the most evolutionarily conserved proteins.
This is because their function in DNA packaging is critical.
Changes in histone structure would disrupt gene expression.
Thus, Statement II is also correct.
Therefore, both statements are correct.

Step 4: Final Answer:
Both Statement I and Statement II are correct.
Hence, the correct option is (C).