Back bone in structure of DNA molecule is made up of -

Options

A. Pentose Sugar and phosphate
B. Hexose sugar and phosphate
C. Purine and pyrimidine
D. Sugar and phosphate

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Structure**: DNA (Deoxyribonucleic Acid) is a molecule that carries genetic information. It is composed of two long strands that form a double helix.

2. **Identifying Components of DNA**: The basic building blocks of DNA are called deoxyribonucleotides. Each deoxyribonucleotide consists of three components:
- A phosphate group
- A deoxyribose sugar (a type of pentose sugar)
- A nitrogenous base (which can be a purine or a pyrimidine)

3. **Backbone of DNA**: The backbone of the DNA molecule is formed by the sugar and phosphate groups. The sugar (deoxyribose) and phosphate groups are linked together by phosphodiester bonds, creating a strong and stable structure.

4. **Types of Sugars**: In the context of DNA, the sugar present is specifically deoxyribose, which is a pentose sugar (a five-carbon sugar). This distinguishes it from hexose sugars, which have six carbon atoms.

5. **Conclusion**: Therefore, the backbone of the DNA molecule is made up of pentose sugar (deoxyribose) and phosphate groups.

**Final Answer**: The backbone in the structure of a DNA molecule is made up of pentose sugar and phosphate.

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