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Molecular Basis of Inheritance · Question 1

NEET (UG) 2026MCQEasy📈 Topic in 88% papers+4−1
1

In the lac operon, the z gene codes for :

  1. the repressor of lac operon
  2. transacetylase
  3. permease
  4. beta-galactosidase

Answer

(4) beta-galactosidase

Solution

As per NCERT, the lac operon has one regulatory gene ( i) and three structural genes ( z, y and a).

i gene ⇒ repressor of the lac operon

z gene ⇒ beta-galactosidase (hydrolyses lactose into galactose and glucose)

y gene ⇒ permease

a gene ⇒ transacetylase

∴ The z gene codes for beta-galactosidase.

Answer: (4)

NEET (UG) 2026

Keep practising — Molecular Basis of Inheritance

2

Arrange the following steps of DNA fingerprinting in a correct sequence. Choose the correct answer from the options given below :

  1. A, E, B, C, D
  2. A, D, B, E, C
  3. A, B, D, C, E
  4. A, E, C, B, D
NEET (UG) 2026
3

Which of the following statements are correct with reference to a transcription unit? Choose the correct answer from the options given below:

  1. B, C, D and E only
  2. A, B, C, D and E
  3. A, B, C and D only
  4. A, C, D and E only
NEET (UG) 2026
4

Which of the following statements are correct with reference to packaging of DNA helix ? Choose the correct answer from the options given below :

  1. B, D and E only
  2. A, B and D only
  3. C, D and E only
  4. A, C and E only
NEET (UG) 2026
5

Which of the following statements about lac-operon is correct?

  1. Galactose can act as an inducer of lac operon
  2. Gene i is constitutively expressed
  3. Lactose activates repressor to bind to the operator
  4. Genes i, z, y and a share single common promoter
RE-NEET (UG) 2026
6

Which of the following enzymes synthesizes precursor mRNA?

  1. DNA polymerase
  2. RNA polymerase I
  3. RNA polymerase II
  4. RNA polymerase III
RE-NEET (UG) 2026
7

Which chromosome in the human genome has the highest number of genes?

  1. Chromosome 1
  2. Chromosome 10
  3. Chromosome X
  4. Chromosome Y
NEET (UG) 2025
8

Match List-I with List-II Choose the correct answer from the options given below:

  1. A-IV, B-III, C-I, D-II
  2. A-III, B-II, C-IV, D-I
  3. A-II, B-IV, C-I, D-III
  4. A-IV, B-II, C-I, D-III
NEET (UG) 2025
9

Which of the following are the post-transcriptional events in a eukaryotic cell? Choose the correct answer from the options given below :

  1. B, C, E only
  2. C, D, E only
  3. A, B, C only
  4. B, C, D only
NEET (UG) 2025
10

Given below are two statements: In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Statement I is correct but statement II is incorrect
  2. Statement I is incorrect but statement II is correct
  3. Both statement I and statement II are correct
  4. Both statement I and statement II are incorrect
NEET (UG) 2025
11

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

  1. Statement I is correct but statement II is incorrect
  2. Statement I is incorrect but statement II is correct
  3. Both statement I and statement II are correct
  4. Both statement I and statement II are incorrect
NEET (UG) 2025

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