In what ways do DNA and RNA differ in terms of strand number, base composition, and type of pentose sugar?

Sourav PanNovember 8, 2024

Answered

DNA and RNA are both essential nucleic acids in biological systems, but they differ significantly in several key aspects: strand number, base composition, and type of pentose sugar.

Strand Number

• DNA: Typically exists as a double-stranded molecule, forming a double helix structure. This double-stranded configuration allows for complementary base pairing, which is crucial for its function in storing genetic information.
• RNA: Generally found as a single-stranded molecule. While RNA can occasionally form double-stranded regions through base pairing, it predominantly functions as a single strand.

Base Composition

• DNA: Contains four nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C). In DNA, adenine pairs with thymine (A-T) and guanine pairs with cytosine (G-C) through hydrogen bonds.
• RNA: Also composed of four nitrogenous bases but substitutes uracil (U) for thymine. Thus, the bases in RNA are adenine (A), uracil (U), guanine (G), and cytosine (C). In RNA, adenine pairs with uracil (A-U) and guanine pairs with cytosine (G-C).

Type of Pentose Sugar

• DNA: The sugar component is called deoxyribose, which lacks an oxygen atom at the 2′ carbon position compared to ribose. This absence is reflected in the name “deoxy”.
• RNA: Contains the sugar ribose, which has a hydroxyl group (-OH) attached to the 2′ carbon. This structural difference contributes to the reactivity and stability of RNA compared to DNA