AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If you have 40 adenine in a DNA molecule, how many thymine can you expect?
A
20
B
30
C
40
D
50
Explanation: 

Detailed explanation-1: -And 20 of them are thymine. If 20 bases are thymine, then 20 bases must be adenine. So that makes 40 bases between adenine and thymine. 100 minus 40 is 60.

Detailed explanation-2: -According to Chargaff’s rule, Concentration of adenine=concentration of thymine. therefore if [A]=40% then the [T] will also be 40%.

Detailed explanation-3: -Answer: There would be 20% Cytosine.

Detailed explanation-4: -Therefore, Guanine would be 20% and total of G+C = 40% and hence A+T would be 60% that is 30% each. Hence, option C is correct answer.

Detailed explanation-5: -Answer and Explanation: A double-stranded DNA molecule with 20% thymine would contain 30% guanine.

There is 1 question to complete.