A sample of DNA has 10% Guanine. What is the percentage of Thymine in that sample?

2 Answers
Jun 21, 2018

#40%#

Explanation:

Guanine (G) in DNA is one-to-one coupled to cytosine (C), so that also makes up for 10%.

Then there's 80% left for the other one-to-one couple: Thymine (T) and adenine (A). So 40% T and 40% A.

Jun 21, 2018

#40%#

Explanation:

In #"DNA"#, adenine #("A")# always bonds with thymine #("T")#, while guanine #("G")# always bonds with cytosine #("C")#.

So, the percentages of #"A"# and #"T"# will be equal, while the percentages of #"G"# and #"C"# would also be equal.

In this sample, there exist #10%# of guanine, therefore there's also #10%# of cytosine. Therefore, thymine and adenine would make up a total of #100%-10%-10%=80%# of the #"DNA"#.

As they must exist in equal amounts, the percentage of thymine in this #"DNA"# sample will be #80%-:2=40%#.