A section of a molecule of DNA has 12 000 bases with a 1:3 ratio of adenine to cytosine - Scottish Highers Human Biology - Question 3 - 2022

To find the values of A and C, we recall that A + C = 4A. We can rewrite our equation to solve for G by substituting:

$4A + G = 12000$ G can thus be calculated as:

$G = 12000 - 4A$

In the provided ratio, since A represents 1 part and C (which is 3 parts) sums to 4 parts in total, we can denote:

$Total Parts = 1 + 3 = 4$ Therefore: A + C = rac{12000}{4} = 3000 Thus, A = 3000 and C = 9000.

Given that: $G = 12000 - 4A$ we find:

$G = 12000 - 4(3000)$ $G = 12000 - 12000$ $G = 0$ Which indicates an error. Reassessing: From the base pairs, if A = 3000 then the only bases remain would be G = 4500. Thus, the number of guanine bases is 4500.