# AP BIOLOGY

## THE MOLECULAR BASIS OF INHERITANCE

### DNA MAKES RNA MAKES PROTEIN

 Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
A strand of DNA is composed of 40% Adenine bases. What percent of bases must be Guanine?
 A 40% B 20% C 10% D 80%
Explanation:

Detailed explanation-1: -According to Chargaff’s rule, Concentration of adenine=concentration of thymine. therefore if [A]=40% then the [T] will also be 40%.

Detailed explanation-2: -It guanine is 40% then cytosine will also be 40%. Similarly, Aenine pairs with thymihne, if guanine is 40%, the remaining 60% will be Adenine. So Theymine will also be 60%.

Detailed explanation-3: -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-4: -In the DNA structure, adenine base always pairs with thymine and cytosine always pairs with guanine. If 10% of the bases in a DNA are adenine, 10% of this DNA molecule must be thymine. The remaining 80% will be made up of 40% cytosine and 40% guanine since the bases pair with each other leaving a ratio of 1:4.

There is 1 question to complete.