Which of the following statement is wrong?

Question

Accepted Answer

Option 2 states that "The pH of histones is less than 7." This statement is incorrect, and here's why:

1. **Explanation for Option 2:**
   - Histones are basic proteins, which means they have a higher pH, typically greater than 7. This basic nature is due to the presence of amino acids like lysine and arginine, which have positively charged side chains at physiological pH. These positive charges allow histones to interact with the negatively charged phosphate groups of DNA, facilitating the packaging of DNA into chromatin. Therefore, the statement that the pH of histones is less than 7 is incorrect because histones are not acidic; they are basic.

2. **Explanation for why other options are correct:**

- **Option 1: "Histones are rich in lysine and arginine."**
     - This statement is correct. Histones are indeed rich in the amino acids lysine and arginine. These amino acids contribute to the basic nature of histones, allowing them to bind effectively to the negatively charged DNA.

- **Option 3: "An octamer of histones is present in nucleosome."**
     - This statement is correct. The nucleosome, which is the fundamental unit of chromatin, consists of an octamer of histones. This octamer is made up of two copies each of histones H2A, H2B, H3, and H4, around which DNA is wrapped.

- **Option 4: "Five types of histones are involved in DNA packaging."**
     - This statement is correct. There are five main types of histones involved in DNA packaging: H1, H2A, H2B, H3, and H4. Histone H1 is involved in the higher-order structure of chromatin, while the others form the core of the nucleosome.

In conclusion, Option 2 is the correct answer because it inaccurately describes the pH nature of histones, which are basic rather than acidic. The other options accurately describe the characteristics and roles of histones in DNA packaging.