Question

Of the following four 15-bp double-stranded DNA sequences, which will be most stable at higher temperatures? In other words, which will most likely remain in a double-stranded form? (Note: only one strand is shown here)
1. CATCCTAGCGACTAT
2. CTATACGACATAGCC
3. AAATGCATACATCTT
4. CCCGCATCGCCATCG​

Answer 1

Answer:

Explanation:

1. CATCCTAGCGACTAT

2. CTATACGACATAGCC

3. AAATGCATACATCTT

4. CCCGCATCGCCATCG

Answer 2

4. CCCGCATCGCCATCG will be most stable at higher temperatures.

• The stability of double-stranded DNA depends upon the number of hydrogen bonds. As per the known fact, adenine and thymine are joined together via two hydrogen bonds.
• And, guanine and cytosine are joined together via three hydrogen bonds.
• Thus, the presence of more number of guanine and cytosine in the strand confers higher stability.