Question

The sequence of nitrogenous bases in one strand of DNA are $3^{\prime }TACGCGACG{5}^{\prime }$. The complementary DNA strand should have

• A. $5^{\prime }AUGCGCTGC{3}^{\prime }$
• B. $3^{\prime }ATGCGCTGC{5}^{\prime }$
• C. $5^{\prime }UACGCGACG{3}^{\prime }$
• D. $5^{\prime }ATGCGCTGC{3}^{\prime }$

Answer 1

Answer: (D)

$5^{\prime }ATGCGCTGC{3}^{\prime }$

• The two-strand of DNA is antiparallel to each other.
• The four nitrogenous bases which form the backbone of the DNA pairs with the complementary base pairs like adenine pairs with thymine while the cytosine pairs with guanine.
• So if the coding on the template strand is 3′TAC GCG ACG 5′ then its complementary strand will have 5′ATG CGC TGC 3′5′ATG CGC TGC 3′.

So, the correct answer is option D.