Question

A researcher measured the temperature at which two different samples of double-stranded DNA denature (separate into single strands) Sample 1 denatured at a significantly lower temperature

than sample 2 did. Based on the data, the researcher claims that the DNA in sample 2 is composed of a higher percentage of guanine and cytosine than the DNA in sample Ils
Which of the following best supports the researcher's claim?
Sube
The bonds between guanine and cytosine are covalent bonds, which require more energy to disrupt than those between adenine and thymine
B
Guanine cytosine pairs denature at a higher temperature because they have more hydrogen bonds between them than adenine-thymine pairs do
с
Aderine thyminepalis require less energy to separate because adenine and thymine are both single-ring bases
D
Guinine cytosine pas require more energy to separate because one is purine and one is a pyrimidine

Answer 1

the correct answer is D

Step-by-step explanation:

i have checked the answer in a flashcard

Answer 2

The correct option is b

Step-by-step explanation:

There are four nitrogenous bases that can be found in a DNA molecule; Adenine, Thymine, Guanine and Cytosine. The adenine on one strand can only bond (hydrogen bond) with the thymine on the complimentary strand (to form base pair) and vice versa while the guanine on one strand can only bond (hydrogen bond) with the cytosine on the complementary strand (to form base pairs) and vice versa.

There are three hydrogen bonds between Guanine and cytosine base pair while there are two hydrogen bonds between adenine and thymine base pair; hence, DNA samples with higher guanine-cytosine base pairs denature at a higher temperature than DNA samples with lower guanine-cytosine base pairs or with more adenine-thymine base pairs. This is because, it requires more energy to break the triple bonds between the guanine-cytosine base pairs than the double bonds of adenine-thymine base pairs.

From the description above, we can deduce that the correct option is b