MCQ ON THE LAC OPERON class 12 for NEET

MCQ ON THE LAC OPERON class 12 for NEET | THE LAC OPERON class 12 | MCQ THE LAC OPERON with Answer | Check the below NCERT MCQ question for class 12 Biology based on the with Answers.

MCQ on THE LAC OPERON class 12 Biology with answers were prepared based on the latest pattern.We have provided class 12 Biology MCQs questions on LINKAGE with Answers to help students understand the concept very well.
MCQ ON THE LAC OPERON is useful for NEET / CSIR / UGC / CBSE / ICSE / AIIMS / EXAM / AFMC EXAM / STATE LEVEL MEDICAL EXAM 2022-23, 2023-24

Introduction:
The Lac Operon is an inducible operon system is that regulated genetic material which remains switched off normally but operational in the presence of an inducer.It occurs in catabolic pathway.The components are structural genes z ,y and a gene and regulatory genes i.Such arrangement is very common in bacteria and is referred to as operon.

MCQ ON THE LAC OPERON class 12 for NEET

1.The Lac operon is regulated by

(a) Lac repressor only
(b) Lac repressor and CAP- cGMP complex
(c) Lac repressor and CAP- cAMP complex
(d) all the above

Ans (c) Lac repressor and CAP- cAMP complex.

2. Lac operon is turned on when allolactose binds to

(a) operator gene
(b) mRNA
(c) Repressor protein
(d) promoter site

Ans. (c) Repressor protein

3. Lac operon consists of

(a) Four regulatory genes only
(b) Two regulatory genes and two structural genes
(c) Three regulatory genes and three structural genes
(d) one regulatory genes and three structural genes

Ans. (d) one regulatory genes and three structural genes

4. Lac operon inducer lactose serves as an enzyme substrate for

(a) Transacetylase
(b) Permease
(c) beta galactosidase
(d) endonuclease

Ans.(c) beta galactosidase

5. A unit of lac operon which is in the absence of lactose , suppresses the activity of operator gene is

(a) structural genes
(b) regulatory genes
(c) repressible protein
(d) promoter genes

Ans.(b) regulatory genes

6. Lac operon was postulated by

(a) Francois Jacob
(b) Jacque Monod
(c) Both a and b
(d) Mendel

Ans.(c) Both a and b

7. In lac operon here lac refers to

(a) lactose
(b) lactic acid
(c) lac
(d) lacuna

Ans.(a) lactose

8. In lac operon , a polycistronic structural gene is regulated by common

(a) promoter
(b) regulatory genes
(c) both a and b
(d) none of the above

Ans.(c) both a and b

9. In lac operon , the i gene codes for

(a) repressor
(b) inhibitors
(c) polygene
(d) all the above

Ans. (a) repressor

10. In lac operon the structural genes Z codes for

(a) beta galactosidase
(b) Permease
(c) Transacetylase
(d) none of the above

Ans. (a) beta galactosidase

11. In lac operon structural genes y genes codes

(a) Permease
(b) beta galactose
(c) translactae
(d) all the above

Ans.(a) Permease

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12. In lac operon the a genes codes for

(a) Permease
(b) beta galactosidase
(c) Transacetylase
(d) both b and c

Ans . (C) Transacetylase

13. All three genes products in lac operon are required for metabolism of

(a) glucose
(b) maltose
(c) lactose
(d) galactose

Ans.(c) lactose

15. The substrate for the enzyme beta galactosidase and it regulates switching in and off of the operon.

(a) lactose
(b) maltose
(c) galactose
(d) all the above

Ans. (a) lactose

16. The repressor of the operon is synthesized from the gene..

(a) y gene
(b) z gene
(c) a gene
(d) i gene

Ans.(d) i gene

17. The Repressor protein binds to …… region of the operon.

(a) operator
(b) promoter
(c) regulator
(d) all the above

Ans.(a) operator

18. Which protein prevents RNA POLYMERASE from transcribing the operon.

(a) The repressor protein
(b) promoter
(c) regulatory
(d) all the above

And.(a) the repressor protein

19. Lac operon is occurs in

(a) anabolic pathway
(b) catabolic pathway
(c) metabolism pathway
(d) none of the above

Ans. (b) catabolic pathway

20. Inducer of lac operon is

(a) lactose
(b) galactose
(c) maltose
(d) all the above

Ans.(a) lactose