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Dna Bases proportion

Hello

I have a question from a past paper:

DNA from a chromosome is analysed and 20 % of its bases are found to be cytosine.Which percentage of uracil molecules will be found in mRNA transcribed from this DNA?

20 B 30 C 40 D 60

I know that one can find out the percentage of guanine molecules ( = 20 % ) But how in the word can I find the % of Uracil molecules.

Thanks.

By the way the answer is B 30 % in the marking scheme.

Reply 1

Number6

Total % = 100
C = 20 therefore G = 20 (they only bind with each other)
C + G + A + T(or U) = 100
20 + 20 + A + T(or U) = 100
A = T(or U)
See what to do next?

Reply 2

Hashmi

Number6

Total % = 100
C = 20 therefore G = 20 (they only bind with each other)
C + G + A + T(or U) = 100
20 + 20 + A + T(or U) = 100
A = T(or U)
See what to do next?