Which of the Following DNA Strands Can Form a DNA

Question

Which of the following DNA strands can form a DNA duplex by pairing with itself at each position?
A)5′-AAGCCGAA-3′
B)5′-AAGCCGTT-3′
C)5′-AAGCGCAA-3′
D)5′-AAGCGCTT-3′

Accepted Answer

In order for a DNA strand to form a duplex by pairing with itself at each position, it must have complementary base pairs. A and T are complementary base pairs, as are C and G. Therefore, the strand must have equal numbers of A and T bases and C and G bases. Option D, 5′-AAGCGCTT-3′, has equal numbers of A, T, C, and G bases, making it the best choice for forming a DNA duplex with itself.