NEET Molecular Basis of Inheritance PYQ practice sheet

20 previous-year NEET Botany questions from Molecular Basis of Inheritance, newest papers first. Molecular Basis of Inheritance carries 47 of the Botany questions in NEET 2020 to 2026, so this is a good place to test yourself after revising the chapter. Marking: +4 correct, −1 wrong.

Practise all 38 online

1.
RE-NEET 2026
Which of the following statements about lac-operon is correct?
- (A)
  Genes i, z, y and a share single common promoter
- (B)
  Lactose activates repressor to bind to the operator
- (C)
  Galactose can act as an inducer of lac operon
- (D)
  Gene i is constitutively expressed
2.
RE-NEET 2026
Which of the following enzymes synthesizes precursor mRNA?
- (A)
  DNA polymerase
- (B)
  RNA polymerase II
- (C)
  RNA polymerase III
- (D)
  RNA polymerase I
3.
NEET 2026
In the lac operon, the z gene codes for
- (A)
  the repressor of lac operon
- (B)
  permease
- (C)
  transacetylase
- (D)
  beta-galactosidase
4.
NEET 2026
Which of the following statements are correct with reference to a transcription unit? A. A transcription unit in DNA is defined primarily by three regions: promoter, structural gene and terminator. B. The promoter is said to be located towards the 5'-end of the structural gene. C. The promoter is a DNA sequence that provides binding site for RNA polymerase. D. The promoter defines the template and coding strands. E. The terminator is located towards the 3'-end of the coding strand and it defines the end of the process of transcription. Choose the correct answer from the options given below:
- (A)
  A, B, C and D only
- (B)
  B, C, D and E only
- (C)
  A, B, C, D and E
- (D)
  A, C, D and E only
5.
NEET 2026
Arrange the following steps of DNA fingerprinting in a correct sequence. A. Isolation of DNA and its digestion by restriction endonucleases. B. Hybridisation using a labelled VNTR probe. C. Transferring of separated DNA fragments to synthetic membranes. D. Detection of hybridised DNA fragments by autoradiography. E. Separation of DNA fragments by electrophoresis. Choose the correct answer from the options given below:
- (A)
  A, B, D, C, E
- (B)
  A, E, C, B, D
- (C)
  A, E, B, C, D
- (D)
  A, D, B, E, C
6.
NEET 2026
Which of the following statements are correct with reference to packaging of DNA helix? A. Histones are organized to form a unit of eight molecules called histone octamer. B. Histones are negatively charged basic proteins. C. Histones are rich in the basic amino acid residues - lysine and arginine. D. The positively charged DNA is wrapped around the histone octamer to form nucleosome. E. The packaging of chromatin at higher levels requires an additional set of proteins called non-histone chromosomal proteins. Choose the correct answer from the options given below:
- (A)
  B, D and E only
- (B)
  A, C and E only
- (C)
  A, B and D only
- (D)
  C, D and E only
7.
NEET 2024
A transcription unit in DNA is defined primarily by the three regions in DNA and these are with respect to upstream and down stream end:
- (A)
  Repressor, Operator gene, Structural gene
- (B)
  Structural gene, Transposons, Operator gene
- (C)
  Promoter, Structural gene, Terminator
- (D)
  Inducer, Repressor, Structural gene
8.
NEET 2024
The lactose present in the growth medium of bacteria is transported to the cell by the action of
- (A)
  Permease
- (B)
  Beta-galactosidase
- (C)
  Polymerase
- (D)
  Acetylase
9.
NEET 2024
Match List-I with List-II. List-I: (A) Frederick Griffith, (B) Francois Jacob & Jacque Monod, (C) Har Gobind Khorana, (D) Meselson & Stahl List-II: (I) Genetic code, (II) Semi-conservative mode of DNA replication, (III) Transformation, (IV) Lac operon Choose the correct answer from the options given below:
- (A)
  A-III, B-II, C-I, D-IV
- (B)
  A-III, B-IV, C-I, D-II
- (C)
  A-II, B-III, C-IV, D-I
- (D)
  A-IV, B-I, C-II, D-III
10.
NEET 2024
Which of the following statement is correct regarding the process of replication in E. coli?
- (A)
  The DNA dependent RNA polymerase catalyses polymerization in one direction, that is 5' $\to$ 3'.
- (B)
  The DNA dependent DNA polymerase catalyses polymerization in 5' $\to$ 3' direction.
- (C)
  The DNA dependent DNA polymerase catalyses polymerization in one direction, that is 3' $\to$ 5'.
- (D)
  The DNA dependent DNA polymerase catalyses polymerization in 5' $\to$ 3' as well as 3' $\to$ 5' direction.
11.
NEET 2024
Which one is the correct product of DNA dependent RNA polymerase to the given template? 3' TACATGGCAAATATCCATTCA 5'
- (A)
  5' ATGTACCGTTTATAGGTAAGT 3'
- (B)
  5' AUGUACCGUUUAUAGGUAAGU 3'
- (C)
  5' AUGUACCGUUUAUAGGGAAGU 3'
- (D)
  5' AUGUAAAGUUUAUAGGUAAGU 3'
12.
NEET 2024
Match List I with List II: List-I: A. RNA polymerase III, B. Termination of transcription, C. Splicing of Exons, D. TATA box List-II: I. snRNPs, II. Promoter, III. Rho factor, IV. snRNAs, tRNA Choose the correct answer from the options given below:
- (A)
  A-II, B-IV, C-I, D-III
- (B)
  A-III, B-II, C-IV, D-I
- (C)
  A-IV, B-III, C-I, D-II
- (D)
  A-III, B-IV, C-I, D-II
13.
NEET 2023
Expressed Sequence Tags (ESTs) refers to
- (A)
  Certain important expressed genes.
- (B)
  All genes that are expressed as RNA.
- (C)
  All genes that are expressed as proteins.
- (D)
  All genes whether expressed or unexpressed.
14.
NEET 2023
Unequivocal proof that DNA is the genetic material was first proposed by
- (A)
  Wilkins and Franklin
- (B)
  Frederick Griffith
- (C)
  Alfred Hershey and Martha Chase
- (D)
  Avery, Macleod and McCarthy
15.
NEET 2023
What is the role of RNA polymerase III in the process of transcription in Eukaryotes?
- (A)
  Transcription of only snRNAs
- (B)
  Transcription of rRNAs (28S, 18S and 5.8S)
- (C)
  Transcription of tRNA, 5srRNA and snRNA
- (D)
  Transcription of precursor of mRNA
16.
NEET 2023
How many different proteins does the ribosome consist of?
- (A)
  20
- (B)
  80
- (C)
  60
- (D)
  40
17.
NEET 2023
Given below are two statements: Statement I: RNA mutates at a faster rate. Statement II: Viruses having RNA genome and shorter life span mutate and evolve faster. In the light of the above statements, choose the correct answer from the options given below:
- (A)
  Statement I false but Statement II is true.
- (B)
  Both Statement I and Statement II are true.
- (C)
  Both Statement I and Statement II are false.
- (D)
  Statement I is true but Statement II is false.
18.
NEET 2023
Given below are two statements: Statement I: In prokaryotes, the positively charged DNA is held with some negatively charged proteins in a region called nucleoid. Statement II: In eukaryotes, the negatively charged DNA is wrapped around the positively charged histone octamer to form nucleosome. In the light of the above statements, choose the correct answer from the options given below:
- (A)
  Statement I incorrect but Statement II is true.
- (B)
  Both Statement I and Statement II are true.
- (C)
  Both Statement I and Statement II are false.
- (D)
  Statement I is correct but Statement II is false.
19.
NEET 2023
Match List I with List II. | List I | List II | |---|---| | A. Gene 'a' | I. $\beta$ -galactosidase | | B. Gene 'y' | II. Transacetylase | | C. Gene 'i' | III. Permease | | D. Gene 'z' | IV. Repressor protein | Choose the correct answer from the options given below:
- (A)
  A-III, B-I, C-IV, D-II
- (B)
  A-II, B-I, C-IV, D-III
- (C)
  A-II, B-III, C-IV, D-I
- (D)
  A-III, B-IV, C-I, D-II
20.
NEET 2023
Which one of the following is the sequence on corresponding coding strand, if the sequence on mRNA formed is as follows 5' AUCGAUCGAUCGAUCGAUCG AUCG AUCG 3' ?
- (A)
  3' ATCGATCGATCGATCGATCG ATCGATCG 5'
- (B)
  5' UAGCUAGCUAGCUAGCUA GCUAGC UAGC 3'
- (C)
  3' UAGCUAGCUAGCUAGCUA GCUAGCUAGC 5'
- (D)
  5' ATCGATCGATCGATCGATCG ATCGATCG 3'

Answer key

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