Question

1. If a strand of DNA has 15% C, what percent will be T?

2. If a strand of DNA has 46% A, what percent will be C?
3. If a strand of DNA has 14% G, what percent will be A?
4. If a strand of DNA has 30% C, what percent will be G?
5. If a strand of DNA has 25% A, what percent will be T?
6. If a strand of DNA has 24% G, what percent will be A?

Answer 1

Answer: 1) 35% 2) 4% 3) 36% 4) 30% 5) 25% 6) 26%

Step-by-step explanation:

According to charagaff's Rule, Purines are equal to Pyrimidines.

A+G=C+T

And in double-stranded DNA Adenine forms a double bond with Thymine and Guanine forms a triple bond with Cytosine.

1) So for the first part, C= 15% and G will be equal C So G=15%

100-30 =70%

Adenine and Thymine are present in same amount.

So the percentage of thymime will be 70/2=35%

2)A= 46% and G will be equal C So T=46%

100-92 =8%

G and C are present in the same amount.

So the percentage of C will be 8/2=4%

3) G= 14% and G will be equal C So G=14%

100-30 =70%

Adenine and Thymine are present in same amount.

So the percentage of adenine will be 72/2=36%

4) C= 30% and G will be equal C So G=30%

5) A= 25% and T will be equal A So T=25%

6)G= 24% and c will be equal G So C=24%

100-48 =52%

Adenine and Thymine are present in same amount.

So percentage of adenine will be 52/2=26%

Key points : Purines are Adenine and Guanine

Pyrimidines are Thymine and Cytosine.

Answer 2

Since DNA base pairs always follow Chargaff's rule, which states that the amount of adenine (A) equals the amount of thymine (T), and the amount of cytosine (C) equals the amount of guanine (G), we can determine the percent of T in a strand of DNA that has 15% C by subtracting the percent of C from 50% (which is the combined percent of A and T). Therefore, the percent of T in this strand of DNA would be 50% - 15% = 35%.
Similarly, we can determine the percent of C in a strand of DNA that has 46% A by subtracting the percent of A from 50%. Therefore, the percent of C in this strand of DNA would be 50% - 46% = 4%.
If a strand of DNA has 14% G, we can determine the percent of A by subtracting the combined percent of G and C from 100%. Therefore, the percent of A in this strand of DNA would be 100% - 14% - (the percent of C, which we don't know) = 36%.
If a strand of DNA has 30% C, we can determine the percent of G by subtracting the percent of C from 50%. Therefore, the percent of G in this strand of DNA would be 50% - 30% = 20%.
Since DNA base pairs always follow Chargaff's rule, which states that the amount of adenine (A) equals the amount of thymine (T), we can determine the percent of T in a strand of DNA that has 25% A by subtracting the percent of A from 50%. Therefore, the percent of T in this strand of DNA would be 50% - 25% = 25%.
If a strand of DNA has 24% G, we can determine the percent of A by subtracting the percent of G from 26% (which is the combined percent of A and T in this case, since the percent of G and C adds up to 74%). Therefore, the percent of A in this strand of DNA would be 26% - 24% = 2%. Note that the percent of T would also be 2%, since A and T always occur in equal amounts in DNA base pairs.