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× y HW1.pdf gy question l Chegg...- S | https: ses/11369 11451 11506.201810/Hw1.pdf Hw1.pdf 3 4 8. The figure shown below is about the effect of salt and GC content on Tm of DNA double helix. Answer whether each of following statement is true (T or false (F) based on information that can be inferred from results in the figure. If the answer is F, please justify your answer (15 pt) 80 A. Increasing heat can denature DNA molecules. 60 Low salt B. The higher the content of A:T base pairs, the higher the melting temperature (Tm) High salt 60 70 80 90 100 C. Increasing salt concentration of the solution make it difficult to denature the double-stranded DNA 12:43 PM 2/3/2013Explanation / Answer
The melting temperature also depends on the salt concentration: in low salt, a given DNA will melt at a lower temperature than in a higher salt concentration. This is because DNA is a polyanionic molecule. The salt "shields" the negative charges on each phosphate. When the charges are NOT shielded, the electrostatic repulsion makes it energetically more favorable to separate the strands.
A.True
B.False. A:T base pairs contains only two hydrogen bonds thus it doesn't much effect on melting temperature.
C.True.
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