Question

DNA is genetic material composed of?

• A. Adenine, phosphate, and ribose
• B. Sugar, fat, and protein
• C. Deoxyribose, phosphate, and nitrogen bases
• D. Carbohydrates, protein, and nucleic acid

Hint:

Nucleotide = Deoxyribose sugar + Phosphate group + Nitrogenous base. This is the basic repeating building block of DNA.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Deoxyribonucleic acid (DNA) is a double-stranded polymer made of repeating monomeric units called nucleotides.

Step 2: Detailed Explanation:
Each nucleotide monomer of DNA is composed of three chemical parts:

• Pentose Sugar: Specifically, deoxyribose (a 5-carbon sugar lacking one oxygen atom compared to ribose).

• Phosphate Group: Links the sugars of adjacent nucleotides together via phosphodiester bonds, forming the structural backbone of the DNA.

• Nitrogenous Bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G), which project inward from the sugar-phosphate backbone and participate in complementary base pairing.
Let us evaluate the other options:
- Option (A) is incorrect because ribose sugar is found in RNA, not DNA.
- Option (B) is incorrect because DNA does not contain fats or proteins in its core chemical monomer.
- Option (D) describes general macromolecular classes rather than the precise chemical components of DNA.

Step 3: Final Answer
DNA is composed of deoxyribose sugar, a phosphate group, and nitrogenous bases.