Histone is a basic protein due to the presence of :

Options

A. Alanine & glycine
B. Methionine & serine
C. Tryptophan & tyrosine
D. Lysine & Arginine

Answer

**Step-by-Step Solution:**

1. **Understanding Histones**: Histones are proteins that play a crucial role in the packaging of DNA in eukaryotic cells. They help in condensing DNA into a compact structure known as chromatin.

2. **Composition of Histones**: Histones are composed of a specific set of proteins, primarily including H1, H2A, H2B, H3, and H4. These proteins come together to form a structure known as the histone octamer, which consists of eight histone proteins.

3. **Basic Nature of Histones**: Histones are classified as basic proteins. This classification is primarily due to their high content of basic amino acids, specifically lysine and arginine. These amino acids have positively charged side chains at physiological pH, which contributes to the basic nature of histones.

4. **Function of Basic Amino Acids**: The presence of lysine and arginine allows histones to interact strongly with the negatively charged DNA. This interaction is essential for the wrapping and spooling of DNA around histones, facilitating the formation of nucleosomes and ultimately compacting the DNA.

5. **Conclusion**: Therefore, histones are termed basic proteins because of their high content of lysine and arginine, which are responsible for their positive charge and their ability to bind tightly to negatively charged DNA.

**Final Answer**: Histone is a basic protein due to the presence of lysine and arginine.

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