NCERT Solutions for Class 12 Biology Chapter 6

Molecular Basis of Inheritance Class 12

Chapter 6 Molecular Basis of Inheritance Exercise Solutions

<< Previous Chapter 5 : Principles of Inheritance and Variation Next Chapter 7 : Evolution >>

Exercise : Solutions of Questions on Page Number : 125

Q1 :  

Group the following as nitrogenous bases and nucleosides:

Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine.


Answer :

Nitrogenous bases present in the list are adenine, thymine, uracil, and cytosine.

Nucleosides present in the list are cytidine and guanosine.

Answer needs Correction? Click Here

Q2 :  

If a double stranded DNA has 20 per cent of cytosine, calculate the per cent of adenine in the DNA.


Answer :

According to Chargaff's rule, the DNA molecule should have an equal ratio of pyrimidine (cytosine and thymine) and purine (adenine and guanine). It means that the number of adenine molecules is equal to thymine molecules and the number of guanine molecules is equal to cytosine molecules.

% A = % T and % G = % C

If dsDNA has 20% of cytosine, then according to the law, it would have 20% of guanine.

Thus, percentage of G + C content = 40%

The remaining 60% represents both A + T molecule. Since adenine and guanine are always present in equal numbers, the percentage of adenine molecule is 30%.

Answer needs Correction? Click Here

Q3 :  

If the sequence of one strand of DNA is written as follows:

5'-ATGCATGCATGCATGCATGCATGCATGC-3'

Write down the sequence of complementary strand in 5' → 3' direction


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q4 :  

If the sequence of the coding strand in a transcription unit is written as follows:

5'-ATGCATGCATGCATGCATGCATGCATGC-3'

Write down the sequence of mRNA.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q5 :  

Which property of DNA double helix led Watson and Crick to hypothesise semi-conservative mode of DNA replication? Explain.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q6 :  

Depending upon the chemical nature of the template (DNA or RNA) and the nature of nucleic acids synthesised from it (DNA or RNA), list the types of nucleic acid polymerases.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q7 :  

How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q8 :  

Differentiate between the followings:

(a) Repetitive DNA and Satellite DNA

(b) mRNA and tRNA

(c) Template strand and Coding strand


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q9 :  

List two essential roles of ribosome during translation.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q10 :  

In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q11 :  

Explain (in one or two lines) the function of the followings:

(a) Promoter

(b) tRNA

(c) Exons


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q12 :  

Why is the Human Genome project called a mega project?


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q13 :  

What is DNA fingerprinting? Mention its application.


Answer :

Please Register/Login to get access to all solutions Facebook Login
Q14 :  

Briefly describe the following:

(a) Transcription

(b) Polymorphism

(c) Translation

(d) Bioinformatics


Answer :

Please Register/Login to get access to all solutions Facebook Login
<< Previous Chapter 5 : Principles of Inheritance and Variation Next Chapter 7 : Evolution >>

Biology : CBSE NCERT Exercise Solutions for Class 12th for Molecular Basis of Inheritance will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

Popular Articles