Which of the following components is not present in a nucleotide?

• A. Amino acid
• B. $\text{Pentose sugar}$
• C. $\text{Phosphate group}$
• D. $\text{Nitrogenous base}$

Answer: (A)

Verified step by step guidance

1. Understand the structure of a nucleotide: A nucleotide is composed of three main components: a pentose sugar, a phosphate group, and a nitrogenous base.
2. Identify the role of each component: The pentose sugar forms the backbone of the nucleotide, the phosphate group links nucleotides together, and the nitrogenous base is involved in base pairing.
3. Recognize that amino acids are the building blocks of proteins, not nucleotides.
4. Compare the given options with the components of a nucleotide: Pentose sugar, phosphate group, and nitrogenous base are all components of a nucleotide.
5. Conclude that the component not present in a nucleotide is the amino acid, as it is not part of the nucleotide structure.