The base sequence in one of the strands of DNA is TAGCATGAT.
(i) Give the base sequence of the complementary strand.
(ii) How are these base pairs held together in a DNA molecule?
(iii) Explain the base complementarity rule. Give the name of the scientist who framed this rule?

Explanation

(i) ATCGTACTA
{ii) Base pairs are held together by weak hydrogen bonds, adenine pairs with thymine by two H-bonds and guanine pairs with cytosine forming three H-bonds.
(iii) According to base complementarity rule formed by Erwin Cbargaff for a double-stranded DNA, the ratios berween adenine-thymine and guanine-cytosine are constant and equal to one.