0
You visited us 0 times! Enjoying our articles? Unlock Full Access!
Question

The amount of guanine in a sample of DNA sequence is found to be 32%. Which of the following is true for the composition of DNA sample?
  1. It consists of 18% cytosine and 18% thymine.
  2. It consists of 18% adenine and 18% cytosine.
  3. It consists of 32% cytosine and 18% thymine.
  4. It consists of 32% adenine and 18% cytosine.
  5. It consists of 32% thymine and 18% adenine.

A
It consists of 32% cytosine and 18% thymine.
B
It consists of 32% thymine and 18% adenine.
C
It consists of 18% adenine and 18% cytosine.
D
It consists of 32% adenine and 18% cytosine.
E
It consists of 18% cytosine and 18% thymine.
Solution
Verified by Toppr

According to Chargaff’s rule, in all cellular DNAs, regardless of the species, number of adenosine residues is equal to number of thymidine residues which means that A = T; and the number of guanosine residues is equal to the number of cytidine residues; G = C. Hence that the sum of the purine residues equals the sum of the pyrimidine residues; i.e., A + G = T + C. Here [G] = 32% therefore, % of [C] is also 32%. Thus, [A] + [T] = 100 - 64 = 36 %. [A] = 18% and [T] = 18%.
Therefore, the correct answer is option C.

Was this answer helpful?
0
Similar Questions
Q1
While analysing the DNA of an organism, a total number of 5386 nucleotides were found, out of which the proportion of different bases were adenine = 18 %, guanine = 32 %, cytosine = 32 % and thymine = 18 %. Considering the Chargaff’s rule, it can be concluded that
View Solution
Q2
Two stretches of DNA, A and B are taken for a polymerase chain reaction. If DNA-A has more guanine-cytosine bases than adenine-thymine and DNA-B has more adenine-thymine bases than guanine-cytosine bases, which of the following statements is true regarding PCR of these two stretches of DNA?
View Solution
Q3

Statement 1: The four nitrogen bases in a DNA molecule are guanine, thymine adenine, cytosine.

Statement 2: Where adenine and thymine are purines and guanine and cytosine are pyrimidines.


View Solution
Q4
If adenine makes 30% of the DNA molecule, what will be the percentage of thymine, guanine and cytosine in it?
View Solution
Q5
Nitrogenous base present in DNA are
(a) Thymine
(b) Cytosine
(c) Adenine
(d) Guanine
View Solution