Question

assume that in a 50 - base - pair dna fragment (total 100 bases in both strands) there are 10 cytosines. how many total adenines are there in the fragment? 50 80 10 40

Explanation:

Step1: Recall base - pairing rules

In DNA, cytosine (C) pairs with guanine (G), and adenine (A) pairs with thymine (T). So, the number of C = number of G, and the number of A= number of T.

Step2: Determine number of G

Given there are 10 cytosines. Since C = G, there are also 10 guanines.

Step3: Calculate sum of C and G

The sum of C and G is \(10 + 10=20\).

Step4: Calculate sum of A and T

The total number of bases in the DNA fragment is 100. So the sum of A and T is \(100-(10 + 10)=80\).

Step5: Determine number of A

Since A = T, the number of adenines is \(\frac{80}{2}=40\).

Answer:

40