# NEET BIOLOGY

## CELL STRUCTURES AND FUNCTION

### BIO MOLECULES

 Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If a cell has 20% Adenine in it, what % of Cytosine must it have?
 A 10% B 20% C 30% D 80%
Explanation:

Detailed explanation-1: -Since adenine is 20%, then thymine is 20% as well. The total of both is 40%. From 100 remains 60% which is divided equally between guanine and cytosine, so each is 30%.

Detailed explanation-2: -Answer: There would be 20% Cytosine. Adenine (30%) = Thymine (30%) Guanine (20%) = Cytosine (20%)

Detailed explanation-3: -If you have 20% of adenine than you have 20% of thymine, because the amount of adenine and thymine is equal. 20% plus 20% is 40% of adennine and thymine. From 100% DNA bases subtract 40% and you will get 60%.

Detailed explanation-4: -Since cytosine and guanine are always present in equal numbers, the percentage of guanine molecule is 30%.

Detailed explanation-5: -Hence, the sum of the purine residues equals the sum of the pyrimidine residues; i.e. A + G = T + C. Here, [A] = 30%, therefore, % of [T] is also 30%. Thus, [G]+[C] = 100-60 = 40%.

There is 1 question to complete.