Questions & Answers

‘DNA’ stands for
A. Denucleic acid
B. Detoxiribonucleic acid
C. Deoxyribonucleic acid
D. Deoxyrinonucleic acid

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Hint: DNA is a nucleic acid made up of two strands having a sugar phosphate backbone each. This sugar phosphate backbone holds the nucleotides perpendicular to the backbone. The sugar phosphate backbone is made up of alternating phosphate groups and a Deoxyribose sugar.

Complete answer:
-DNA stands for Deoxyribonucleic acid, as it is a nucleic acid made up of Deoxyribose sugar that lacks an –OH group at C2' position unlike a ribose sugar seen in RNA (Ribonucleic acid).
-The sugar is called Deoxyribose as it lacks an oxygen atom at the C2' position. The absence of this oxygen helps the enzymes distinguish DNA from RNA thus making possible the sequence specific recognition of DNA by enzymes and different proteins.
Figure 1: Nucleic acid structure

Additional information:
Apart from the sugar the DNA can be distinguished from RNA based on the nucleotides present, that is, DNA has four basic units called Adenine, Guanine, Cytosine, and Thymine. But in RNA the Thymine is replaced by Uracil, making it a distinguishing feature among DNA and RNA.

Nucleic acids are the large biomolecules that make up the hereditary material in an organism. It is basically made up of three substances: Sugar molecule (ribose or Deoxyribose), phosphoric acid, and a base (purines and pyrimidines). When a base binds to the sugar molecules it forms a nucleoside. This nucleoside then binds with phosphoric acid to form a nucleotide. Hence, a nucleic acid is known as a long chain polymer of nucleotides.