AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If there is 23% Guanine in a DNA molecule, how much Cytosine exists in the same molecule?
A
23%
B
46%
C
54%
D
27%
E
0%
Explanation: 

Detailed explanation-1: -DNA bases bond in pairs with Thymine to Adenine and Guanine to Cytosine. For every one Thymine there will be one Adenine. So, 23% Thymine would mean that there is also 23% Guanine.

Detailed explanation-2: -If the DNA of a species has 23% cytosine, there also will be 23% of the complementary base, guanine. Thymine and its complementary base, adenine, will each make up 27%.

Detailed explanation-3: -Therefore the base percentage of GC is 54% in the whole DNA sequence.

Detailed explanation-4: -So, the correct option is ‘27%’.

There is 1 question to complete.