The nucleic acids DNA and RNA are made of repeating units called?
The correct answer and explanation is:
Correct Answer:
Nucleotides
Explanation (300 words):
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are both essential biomolecules that carry genetic information in living organisms. These nucleic acids are made up of repeating units called nucleotides, which serve as the building blocks of DNA and RNA strands.
A nucleotide has three main components:
- A phosphate group
- A five-carbon sugar
- Deoxyribose in DNA
- Ribose in RNA
- A nitrogenous base, which can be one of the following:
- Adenine (A)
- Thymine (T) – found only in DNA
- Uracil (U) – found only in RNA
- Cytosine (C)
- Guanine (G)
In DNA, nucleotides are arranged in two long strands that form a double helix. The nitrogenous bases on opposite strands pair specifically—adenine with thymine, and cytosine with guanine—through hydrogen bonds. In RNA, which is usually single-stranded, uracil replaces thymine and pairs with adenine.
The sequence of nucleotides in DNA carries the genetic code, which provides the instructions for building proteins. During transcription, a segment of DNA is copied into RNA, which can then be translated into a protein by the ribosomes.
The structure of nucleotides is critical to their function. The phosphate and sugar form the backbone of the nucleic acid strand, while the nitrogenous bases project inward and carry the actual genetic information through their specific sequences and base-pairing rules.
In summary, nucleotides are the fundamental units that make up the long chains of DNA and RNA. Understanding nucleotides helps explain how genetic information is stored, copied, and used in all living organisms.