NEET Previous Year Questions(PYQs) MCQs on Molecular Basis of Inheritance Class-XII Biology

Question 41 of 50

🟢 NEET 2019 📘 CLASS XII

Match the following genes of the Lac operon with their respective products.

(A)i gene	(I)β-galactosidase
(B)z gene	(II)Permease
(C)a gene	(III)Repressor
(D)y gene	(IV)Transacetylase

Select the correct option.

Explanation will be generated when opened.

Question 42 of 50

🟢 NEET 2024 📘 CLASS XII

The lactose present in the growth medium of bacteria is transported to the cell by the action of:

Explanation: NCERT Page No.101, (Topic-5.8.1 The Lac operon)

Question 43 of 50

🟢 NEET 2024 📘 CLASS XII

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:

Explanation: NCERT Page No.91, (Topic-5.5.1 Transcription Unit)

Question 44 of 50

🟢 NEET 2024 📘 CLASS XII

Match List-I with List-II:

	List-I		List-II
A.	Rose	I.	Twisted aestivation
B.	Pea	II.	Perigynous flower
C.	Cotton	III.	Drupe
D.	Mango	IV.	Marginal placentation

Choose the correct answer from the options given below:

Explanation: NCERT Page No.84, (Topic-5.2 THE SEARCH FOR GENETIC MATERIAL)

Question 45 of 50

🟢 NEET 2024 📘 CLASS XII

Which of the following statement is correct regarding the process of replication in E.coli?

NCERT Page No.90, (Topic-5.4.2 The Machinery and the Enzymes)

Question 46 of 50

🟢 Re NEET 2026 📘 CLASS XII

Which of the following enzymes synthesizes precursor mRNA?

In eukaryotes, RNA polymerase II synthesizes heterogeneous nuclear RNA (hnRNA), the precursor of mRNA.

Question 47 of 50

🟢 NEET 2026 📘 CLASS XII

In the lac operon, the z gene codes for:

The lacZ gene encodes β-galactosidase, which hydrolyses lactose into glucose and galactose.

Question 48 of 50

🟢 NEET 2026 📘 CLASS XII

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 the 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 defines the end of transcription.

Choose the correct answer from the options given below:

All the given statements correctly describe the organisation and function of a transcription unit.

Question 49 of 50

🟢 NEET 2026 📘 CLASS XII

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:

Histones form an octamer and are rich in lysine and arginine. DNA is negatively charged, while histones are positively charged. Higher-order chromatin packaging requires non-histone chromosomal proteins.

Question 50 of 50

🟢 NEET 2026 📘 CLASS XII

The sixth mutant codon of beta globin gene causing polymerization of haemoglobin and change in RBC shape is ______.

In sickle-cell anaemia, the sixth codon of the β-globin gene changes from GAG (glutamic acid) to GUG (valine), causing haemoglobin polymerization.

Molecular Basis of Inheritance NEET PYQs