Question

The basic unit of nucleic acid is

• A. pentose sugar
• B. nucleoid
• C. nucleoside
• D. nucleotide.

Answer 1

The Correct Option is D

The question asks us to identify the basic unit of nucleic acid from the given options. Let's go through the options one by one:

1. Pentose sugar: A pentose sugar is a part of the nucleic acid structure, specifically found in the backbone of DNA and RNA, such as ribose in RNA and deoxyribose in DNA. However, by itself, it is not the basic unit of nucleic acids.
2. Nucleoid: This term refers to the irregularly-shaped region within a prokaryote cell that contains all or most of the genetic material. It is not related to the individual components of nucleic acids.
3. Nucleoside: Nucleosides are composed of a nitrogenous base attached to a sugar (either ribose or deoxyribose). Although important, nucleosides do not contain the phosphate group that is essential to form nucleotides.
4. Nucleotide: Nucleotides are the actual basic units or building blocks of nucleic acids. They consist of three components: a nitrogenous base, a five-carbon sugar (pentose), and one or more phosphate groups. Nucleotides link together via phosphodiester bonds to form the long polymer strands of DNA and RNA.

Thus, the correct answer is nucleotide, as it is the basic unit that makes up the structure of nucleic acids, like DNA and RNA.