Question

Which option correctly lists all three components of a single DNA nucleotide?

• A. Phosphate, two nitrogen bases and a deoxyribose sugar
• B. Deoxyribose sugar, a nitrogen base and a phosphate
• C. Deoxyribose sugar, two phosphates and a nitrogen base
• D. Deoxyribose sugar, phosphate and an amino acid

Hint:

Remember: Nucleotide = Sugar + Base + Phosphate. Nucleoside = Sugar + Base (no phosphate).

Answer 1

The Correct Option is B

Step 1: Understand the structure of a nucleotide.
A nucleotide is the basic structural unit of DNA. Each nucleotide is composed of three essential components which together form the building block of the DNA molecule.
Step 2: Identify the three components.
A DNA nucleotide consists of:

• A deoxyribose sugar
• A nitrogenous base (such as adenine, thymine, cytosine, or guanine)
• A phosphate group

Step 3: Analyze the options.

• (A) Incorrect. A nucleotide contains only one nitrogen base, not two.
• (B) Correct. It correctly lists sugar, base, and phosphate.
• (C) Incorrect. A nucleotide has only one phosphate group in its basic unit.
• (D) Incorrect. Amino acids are components of proteins, not nucleotides.

Step 4: Conclusion.
Thus, the correct components of a DNA nucleotide are deoxyribose sugar, nitrogen base, and phosphate group.
Final Answer:} Deoxyribose sugar, a nitrogen base and a phosphate.