Question

The sequence of bases on a single stranded DNA is 3'- CAATGCCCGCCTTGGCATTA-5' Calculate the proportiin of four nucleotides A,T,C,G in the double stranded DNA formed after annealing (means for complementry sequences of single stranded DNA or RNA to pair by hydrogen bond to form double stranded polynucleotide?
A) A= 25%,T=20%,C=20%,G=35% (B) A=25%,T=25%, C= 25% , G=25% (C) A 22.5%,
T=22.5% , C= 27.5%, G= 27.5%
(PLEASE SOLVE THIS QUESTION ITS RIGHT ANS IS C BUT HOW PLEASE TELL ME THE REASON)​

Answer 1

See total no. Of A+T = 9 C+G=11

Total 20

Percentage can be calculated withiut looking over fof the second strand

So now 9/20 ×100 =45% that is total A+T

And we know A=T for a double stranded DNA so 45 /2 22.5 % for A and T...simmillarly for G and C