Question

Which do you suppose is likely to contain more G-C pairings in the genome versus more A-T pairings. A) An organism living in your throat (37 C) B) An organsim living in hot springs (55 C) Choose one and explain why.

Answer 1

The stability of the DNA is one of the most important thing for living organisms. DNA is double helical structure and composed with four nitrogen bases those are A, T, G and C. A binds to T with two hydrogen bonds and G binds to C with three hydrogen bonds or vice versa.

The energy requried to break two hydrogen bonds (between A and T) is less when compared with the energy which is requried to break three hydrogen bonds (between G and C).

So, the organisms which can grow at 37C is contains more AT content and less GC content. Where as the organisms living in the hot spring contain more GC than AT (because the DNA with maximum GC content requires more energy for denaturation when compared with AT.)

So, the answers are

A) An organism living in your throat (37 C) - likely to contain more A-T pairings

B) An organsim living in hot springs (55 C)  - likely to contain more G-C pairings