Nucleoside is made up of
**Question:** Nucleoside is made up of
A. sugar
B. base
C. both sugar and base
D. phosphate group
**Correct Answer:** C. both sugar and base
**Core Concept:** Nucleosides are the building blocks of nucleic acids, including DNA and RNA. These nucleosides consist of a sugar molecule (deoxyribose or ribose) attached to a nitrogenous base (adenine, guanine, cytosine, or uracil).
**Why the Correct Answer is Right:** Nucleosides contain two essential components: a sugar and a base. Deoxyribose is the sugar component in DNA, while ribose is the sugar component in RNA. The bases in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T), while the bases in RNA are adenine (A), guanine (G), cytosine (C), and uracil (U).
**Why Each Wrong Option is Incorrect:** Option A (sugar) is partially correct, as nucleosides do have sugars, but the full nucleoside consists of both sugar and base. Option B (base) is also partially correct, as nucleosides contain nitrogenous bases, but the full nucleoside requires both sugar and base. Option D (phosphate group) is incorrect because nucleotides, not nucleosides, have a phosphate group. Nucleotides are formed by joining one sugar-base pair (deoxyribose-adenine, ribose-adenine, etc.) with a phosphate group.
**Clinical Pearl:** Understanding nucleosides and nucleotides is crucial for understanding molecular biology, particularly for the synthesis of DNA and RNA. Nucleosides and nucleotides play a vital role in genetic information storage, replication, and translation processes in cells.