Question:

If the total amount of adenine and thymine in a double-stranded DNA is $60\%$, the amount of guanine in this DNA will be

  • 0.15
  • 0.2
  • 0.3
  • 0.4
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

Purine and pyrimidine nitrogenous base are found in DNA. Among purines, adenine pairs only with the pyrimidine thymine. Similarly guanine pairs with the cytosine.
The fact that total amount of purine will be equal to total amount of pyrimidine was first enunciated by Chargaff in 1950.
From this law Adenine = Thymine = $60/2 = 30\%$
Guanine = Cytosine = $40/2 = 20\%$
Was this answer helpful?
0
0

Concepts Used:

The Molecular Basis of Inheritance

DNA Replication:

DNA synthesis is commenced at particular points within the DNA strand referred to as ‘origins’, which are certain coding regions. There are numerous origin sites, and when replication of DNA starts, these sites are mentioned as replication forks. Within the replication, the complex is the enzyme DNA Helicase, so that they can be utilized as a template for replication. DNA Primase is another enzyme that's essential in DNA replication.

RNA:

Ribonucleic acid (RNA) is an essential biological macromolecule that exists all together in biological cells. It is principally involved in the synthesis of proteins, that carry the messenger instructions from DNA, which itself contains the genetic instructions needed for the event and maintenance of life. In some viruses, RNA, in spite of DNA, carries genetic information.

Genetic Code:

Genetic code is the term we use in the manner that the four bases of DNA--the A, C, G, and Ts--are strung together in a way that the ribosome, the cellular machinery, can read them and switch them into a protein. In the ordering, every three nucleotides during a row count as a triplet and code for one amino alkanoic acid.

Read More: Molecular Basis of Inheritance