Question

Bacteria and other microbes can be used to clean up" an oil spill by breaking down oil into carbon dioxide and water. Two samples isolated from the Deepwater Horizon leak in the Gulf of Mexico were labeled A and B. The DNA of each was isolated and the percent thymine measured in each sample. Sample A contains 21.7% thymine and sample B contains 28.9% thymine. Assume the organisms contain normal double-stranded DNA and predict the composition of the other bases. percent adenine in sample A: %A percent guanine in sample A: percent cytosine in sample A: percent adenine in sample B: percent guunine in sample B:

Answer 1

Answer :

In DNA , adenine (A) binds with thymine (T) and Guanine (G) binds with cytosine (C) .

Amount of Adenine (A) = Thymine (T)

And , Amount of Guanine (G) = Cytosine (C)

Also, A + T + G + C = 100

Sample A :

Thymine (T) = 21.7 % = Adenine (A) = 21.7 %

G = C , G+C = 2G

Since , A + T + G + C = 100

=> 21.7 + 21.7 + 2G = 100

G = 100-21.7 -21.7 / 2 = 56.6/2 = 28.3 %

So, Guanine (G) = Cytosine (C) = 28.3 %

Sample.B ,

Thymine (T) = 28.9 % = A

So, Adenine (A) = 28.9 %

Also, G = C , G+C = 2G

A + T + G + C = 100

28.9 + 28.9 + 2G = 100

G = 100 - 28.9 - 28.9 / 2 = 42.2 /2 = 21.1

Guanine (G) = 21.1 % = Cytosine (C)

So, Cytosine (C) = 21.1 %

Amount of GC pair is high in sample A , so sample A will have the higher temperature to denature.