Question

The length of DNA having 23 base pair is

• A. $ 78\,\overset{\text{o}}{\mathop{\text{A}}}\, $
• B. $ 78.4\,\overset{\text{o}}{\mathop{\text{A}}}\, $
• C. $ 74.8\,\overset{\text{o}}{\mathop{\text{A}}}\, $
• D. $ 78.2\,\overset{\text{o}}{\mathop{\text{A}}}\, $

Answer 1

Answer: (D)

DNA is helically coiled macromolecule made up of two antiparallel polydeoxyribonucleotide chains held together by hydrogen bonds. One turn of spiral has a distance of $ 34{\AA}. $ It contains 10 nudeotides in each chain so that the distance between adjacent nucleorides is $ 3.4{\AA}. $ Hence, the length of DNA having 23 base pairs is $ 3.4\times 23=78.2{\AA}. $