Question

A DNA nucleotide chain has AGCTTCGA sequence. The nucleotide sequence of other chain would be

• A. TAGCATAT
• B. GATCCTAG
• C. GCTAAGCT
• D. TCGAAGCT

Answer 1

The correct option is D TCGAAGCT

Part 1: Introduction to complementary base pairing
In DNA, the nitrogenous bases of one strand form complementary bases with the nitrogenous bases of the opposite strand. Adenine pairs with thymine and guanine pairs with cytosine.
This implies that if the $5^{\prime }-3^{\prime }$ strand has a nucleotide bearing adenine (A) at a particular position, then the opposite $3^{\prime }-5^{\prime }$ strand will have a nucleotide bearing thymine (T) at the same position and vice versa.
If the $5^{\prime }-3^{\prime }$ strand has a nucleotide bearing cytosine (C) at a particular position, then the opposite $3^{\prime }-5^{\prime }$ strand will have a nucleotide bearing guanine (G) at the same position and vice versa.

Part 2: Nucleotide sequence of other chain
If the nucleotide sequence on one strand is AGCTTCGA, then the complementary nucleotide sequence on the other strand will be TCGAAGCT.

Final answer
(a) TCGAAGCT