What are the subunits (monomers) of nucleic acids such as dna and rna?
The Correct Answer and Explanation is:
The monomers (subunits) of nucleic acids like DNA and RNA are nucleotides. Nucleotides are the basic building blocks that form the long chains of DNA and RNA molecules. Each nucleotide consists of three components:
- A phosphate group: This group is composed of a phosphorus atom bonded to four oxygen atoms and is responsible for linking adjacent nucleotides in the nucleic acid strand through phosphodiester bonds.
- A sugar molecule: The sugar is either deoxyribose in DNA or ribose in RNA. The difference between deoxyribose and ribose is that deoxyribose lacks one oxygen atom compared to ribose. This difference is crucial because it distinguishes DNA from RNA and contributes to their different structural and functional properties.
- A nitrogenous base: This is a nitrogen-containing molecule that can be one of the following:
- Adenine (A),
- Thymine (T) (in DNA only),
- Cytosine (C),
- Guanine (G),
- Uracil (U) (in RNA only).
In DNA, the bases adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G). In RNA, thymine is replaced by uracil (U), so adenine pairs with uracil, and cytosine pairs with guanine.
Function and Structure of Nucleic Acids:
Nucleotides link together through their phosphate groups and sugar molecules to form the sugar-phosphate backbone of a nucleic acid strand. The nitrogenous bases protrude from this backbone and form complementary base pairs, which are crucial for the structure of the double helix in DNA. In RNA, the single-stranded structure is responsible for its role in protein synthesis, among other functions.
DNA stores genetic information in its sequence of nucleotides, while RNA plays a central role in translating this genetic information into proteins. The unique sequence of nucleotides in both DNA and RNA determines the biological information they carry.