Daily Practice Problems
Class 12 Biology
Molecular Basis of Inheritance
daily practice problem

Question 1:

Give the scientific terms for the following:

1. The amino acid coded by the initiation codon in eukaryotes.

2. The region in the transcription unit where the RNA polymerase binds.

3. Intervening sequences which are removed from the mature RNA as they do not code for any protein.

4. A relatively new branch of biology which includes use of high speed computational devices for data storage, retrieval and analysis.

5. A type of satellite DNA used as probes in DNA fingerprinting.


Question 2:

State the contribution of the following scientists:

1. G. Gamow

2. H.G. Khorana

3. Messelson and Stahl

4. Alec Jafferys

5. Hershey and Chase


Question 3:

Expand the following abbreviations:

1. DNA

2. hnRNA

3. UTR

4. HGP



Question 4:

State the role of the following enzymes in DNA replication:

1. DNA polymerase

2. DNA ligase

3. Helicase

4. Primase


Question 5:

Briefly list down the steps involved in the process of DNA fingerprinting.


Question 6:

Define the following terms:

1. Transcription

2. Translation

3. Ori site

4. Exons

5. Splicing


Question 7:

State whether the following statements are true or false.

1. Human genome has 6 billion base pairs.

2. Histone proteins are negatively charged.

3. Chromosome 1 was the first chromosome to be sequenced under Human Genome Project.

4. S - strain of Streptococcus pneumoniae used by Griffith for his experiment was virulent.

5. New strand of DNA is always synthesised in 5’  -->    3’ direction.


Question 8:

With the help of a diagram depict the gene regulation in prokaryotes by Lac operon.


Question 9:

Enlist the various salient observations drawn from the Human Genome Project about the human genome.


Question 10:

Match the columns A and B.

             Column A

Column  B

1. Nucleosome

  a. β- galactosidase

2. AUG

  b. Stop codon

3. UAG

  c. Start codon


  d. Histone proteins

5. lac z

  e. DNA fingerprinting


Question 11:

Who proposed the double helix model of DNA molecule? State its salient features.


Question 12:

What is meant by central dogma? Who proposed it?


Question 13:

State the three stop codons.


Question 14:

What was Griffith’s experiment through which he proposed his theory of transforming principle?


Question 15:

Who confirmed DNA as the genetic material? Give a brief account of the experiment involved.


Question 16:

Why is DNA a better genetic material than RNA?


Question 17:

Given below is a DNA sequence, study the same and answer the questions that follow:

                        3’ – GATTTCGTCAAGTTAACC – 5’

(i) Write down its complementary DNA sequence.

(ii) What will be its mRNA sequence if the above mention strand undergoes transcription?

(iii) State the number of amino acids formed if the mRNA undergoes translation.


Question 18:

Name the three regions that constitute a transcription unit. Depict it with the help of a figure.


Question 19:

Give a brief account of the post-transcriptional modifications in RNA molecule.


Question 20:

Give a few salient features of the genetic code.