Question

There is always a 1 to 1 correspondence between the number guanines (G) and the number of cytosines (C) in a DNA molecule. The same is true of the relationship between adenine (A) and thymine (T). Of course Professor Floop knows this. He analyzed a strand of DNA and determined the amounts of C and G it contained. If the molecule was 22% G, what was the percentage of A, assuming that DNA only contains G, C, A, and T

Answer 1

Answer:

the strand contains 28% of adenine.

Step-by-step explanation:

We have only four components, and we only know one of them:

$\left[\begin{array}{cc}C&?\\G&22\%\\A&?\\T&?\end{array}\right]$

Cytosine has a relation 1 to 1 with G, therefore the strand must contain the same amount of C as it posses G:

$\left[\begin{array}{cc}C&22\%\\G&22\%\\A&?\\T&?\end{array}\right]$

Therefore:

$A + T = 100\% - (C+G)$

This is because the strain only contains those 4 components.

since A and T have also a 1 to 1 relation, we can state that A = T in quantity.

So:

$A + A = 100\% - (C+G)$

$2A = 100\% - (22\%+22\%)$

$A = \frac{100\%-44\%}{2}$

$A = \frac{56%}{2}$

$A = 28\%$