PYQ NEET MCQ Chapter 6: Molecular Basis of Inheritance

Hola NEET aspirants! After learning about principles that genes follow when inheritance happens and the variations that they go through, we come upon the Molecular Basis of this inheritance. This chapter starts with the discovery, structure and functions of genetic material i.e. DNA and RNA. Then we go onto The Central Dogma, how DNA Replicates, how transcription happens from DNA to produce mRNA and finally how mRNA forms proteins by translation. In the end, we also have a look at the Human Genome Project and DNA Fingerprinting.  Let’s have a look at Molecular Basis of Inheritance NEET Previous Year Questions. 

ATTEMPT ALL QUESTIONS BY YOURSELF FIRST THEN CHECK THE SOLUTIONS. BRIEF EXPLANATIONS ABOUT THE SOLUTIONS ARE GIVEN AT THE END AS WELL.

Molecular Basis of Inheritance NEET Previous Year Questions

Questions from 2021

1. Complete the flowchart on central dogma. (2021)

(a) ↻DNA →  (b)  → mRNA  →    (c) →  (d)

(1) (a)-Replication; (b)-Transcription;(c)-Translation; (d)-Protein

(2) (a)-Transduction; (b)-Translation; (c)-Replication; (d)-Protein

(3) (a)-Replication; (b)-Transcription; (c)-Transduction; (d)-Protein

(4) (a)-Translation; (b)-Replication; (c)-Transcription; (d)-Transduction

2. What is the role of RNA polymerase III in the process of transcription in eukaryotes? (2021)

(1) Transcribes precursor of mRNA

(2) Transcribes only snRNAs

(3) Transcribes rRNAs (28S, 18S and 5.8S)

(4) Transcribes tRNA, 5S rRNA and snRNA

3 .Identify the correct statement. (2021)

(1) The coding strand in a transcription unit is copied to an mRNA. 

(2) Split gene arrangement is characteristic of prokaryotes. 

(3) In capping, methyl guanosine triphosphate is added to the 3′ end of hnRNA.

(4) RNA polymerase binds with the Rho factor to terminate the process of transcription in bacteria.

4. Which of the following RNAs is not required for the synthesis of protein? (2021)

(1) siRNA

(2) mRNA

(3) rRNA

(4) tRNA

5. Which is the “Only enzyme” that has the “Capability” to catalyse Initiation, Elongation and Termination in the process of transcription in prokaryotes? (2021)

(1) DNA Ligase 

(2) DNase

(3) DNA dependent DNA polymerase

(4) DNA dependent RNA polymerase

6. Statement I:  (2021) The codon ‘AUG’ codes for methionine and phenylalanine. 

Statement II :’AAA’ and ‘AAG’ both codons code for the amino acid lysine.

In the light of the above statements, choose the correct answer from the options given below. (2021)

(1) Statement I is correct but Statement II is false

(2) Statement I is incorrect but Statement II is true

(3) Both Statement I and Statement II are true

(4) Both Statement I and Statement II are false

7. Which one of the following statements about Histones is wrong? (2021)

(1) Histones are rich in amino acids – Lysine and Arginine. 

(2) Histones carry a positive charge in the side chain.

(3) Histones are organised to form a unit of 8 molecules. 

(4) The pH of histones is slightly acidic.

Questions from 2020

8. If the distance between two consecutive base pairs is 0.34 nm and the total number of base pairs of a DNA double helix in a typical mammalian cell is 6.6×109 bp, then the length of the DNA is approximately: (2020)

(1) 2.5 metres

(2) 2.2 metres

(3) 2.7 metres

(4) 2.0 metres

9. The first phase of translation is: (2020)

(1) Recognition of DNA molecule

(2) Aminoacylation of tRNA

(3) Recognition of an anticodon

(4) Binding of mRNA to the ribosome

10. Name the enzyme that facilitates the opening of the DNA helix during transcription. (2020)

(1) DNA helicase

(2) DNA polymerase

(3) RNA polymerase

(4) DNA ligase

Questions from 2018-2019

11. What will be the sequence of (mRNA) produced by the following stretch of DNA? (Odisha NEET 2019)

3′ ATGCATGCATGCATG 5′ TEMPLATE STRAND

5′ TACGTACGTACGTAC 3′ CODING STRAND

(a) 3′ AUGCAUGCAUGCAUG 5′

(b) 5′ UACGUACGUACGUAC 3′

(c) 3′ UACGUACGUACGUAC 5′

(d) 5′ AUGCAUGCAUGCAUG 3′ 

12. Which of the following features of genetic code does allow bacteria to produce human insulin by recombinant DNA technology? (2019)

(a) Genetic code is specific.

(b) Genetic code is not ambiguous.

(c) Genetic code is redundant.

(d) Genetic code is nearly universal.

13. Under which of the following conditions there will be no change in the reading frame of the following mRNA? (2019)

5′ AACAGCGGUGCUAUU 3′

(a) Deletion of GGU from 7th, 8th and 9th positions

(b) Insertion of G at 5th position

(c) Deletion of G from 5th position

(d) Insertion of A and G at 4th and 5th. position respectively

14. Expressed Sequence Tags (ESTs) refers to (2019)

(a) novel DNA sequences

(b) genes expressed as RNA

(c) polypeptide expression

(d) DNA polymorphism.

15. The experimental proof for semi-conservative replication of DNA was first shown in a (2018)

(a) fungus

(b) bacterium

(c) plant

(d) virus.

16. Select the correct match. (2018)

(a) Ribozyme- Nucleic acid

(b) F₂ x Recessive parent – Dihybrid cross

(c) T.H. Morgan- Transduction

(d) G. Mendel -Transformation

17. Select the correct statement. (2018)

(a) Franklin Stahl coined the term “linkage”.

(b) Punnett square was developed by a British scientist.

(c) Spliceosomes take part in translation.

(d) Transduction was discovered by S. Altman. 

18. Many ribosomes may associate with a single mRNA to form multiple copies of a polypeptide simultaneously. Such strings of ribosomes are termed as (2018)

(a) polysome

(b) polyhedral bodies

(c) plastidome

(d) nucleosome.

19. Select the correct match. (2018)

(a) Alec Jeffreys – Streptococcus pneumoniae

(b) Alfred Hershey and Martha Chase – TMV

(c) Matthew Meselson and F. Stahl  – Pisum sativum

(d) Francois Jacob and Jacques Monod – Lac operon

20. All of the following are part of an operon except (2018)

(a) an operator

(b) structural genes

(c) an enhancer

(d) a promoter.

Well done buddy! A guide to Molecular Basis of Inheritance NEET Previous Year Questions is incomplete without solutions and explanations, let’s find out!

Solutions of Molecular Basis of Inheritance NEET Previous Year Questions

1. 1
2. 4
3. 4
4. 1
5. 4
6. 2
7. 4
8. 2
9. 2
10. 3
11. B
12. D
13. A
14. B
15. B
16. A
17. B
18. A
19. D
20. C

Short Explanation of Solutions 

1. Central Dogma was given by Crick. DNA Replicates itself in option a. In option b DNA Transcription takes place to form mRNA. mRNA will translate i.e. option c and by translation, it will form proteins i.e. option d.
2. RNA Polymerase 3 produces tRNA that helps in translation, 5SrRNA and snRNA. mRNA is produced by RNA Polymerase 2.
3. The template strand is transcribed to produce mRNA. Split gene arrangement is seen in eukaryotes due to the presence of introns, capping is done at 5’ end and binding with Rho factors terminates transcription, hence option 4 is correct.
4. siRNA is not involved in translation, it is short interfering RNA involved in RNA interference technique in GMO plants. Rest all RNA are involved in translation.
5. Out of all the options only DNA dependent RNA Polymerase is involved in Transcription no other options are.
6. Statement 1 is false because AUG is a start codon and codes for methionine only.  Statement 2 is correct AAA and AAG do code for Lysine.
7. The pH of Histones is slightly basic.
8. If we multiply the distance between each base pair and the total number of bases we will get the length of DNA. In this case, it will be 2.2 metres.
9. The first step of translation is the activation of the adapter t-RNA molecule by aminoacylation of it.
10. Out of all the enzymes only RNA Polymerase plays a role in transcription.
11. The mRNA produced will have the same sequence as the sequence of the coding strand. Only thymine will be replaced by uracil.
12. Since genetic code is universal, the codons that code for certain proteins in humans will also code for those proteins in bacteria. Hence with recombinant DNA technology, we can produce human insulin with the help of bacteria.
13. If GGU is removed from 7, 8 and 9 positions a complete codon will be deleted, and since each codon has three bases no shift in the reading frame will occur.
14. In the human genome project, we use EST ( expressed sequence tags ) that express genes in the form of RNA.
15. Experimental proof by Meselson and Stahl showed DNA Replication in E.Coli which is a bacteria.
16. Ribozymes are RNA that act as enzymes. Hence they are nucleic acids.
17. Punnett square was developed by British Scientist Reginald C.Punnett. Spliceosomes come into the picture in transcription, not translation.
18. A string of ribosomes on mRNA is called polyribosome or polysome.
19. Francis Jacob (geneticist) and J.Monad (biochemist) discovered Lac Operon.
20. Lac Operon has an operator gene (o) that operates the operon, a structural gene (z,y, a) that transcribes to form mRNA and proteins, a promoter gene (p) just before the operator gene but no enhancer gene.

Make sure to check previous year’s questions of other chapters on our website. Keep studying!

Team MBD

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