MCQs Questions For Lac Operon For NEET and Medical Exam 2022

NEET Biology is the scoring paper in the medical entrance examination. Here, you will discover the NEET Biology MCQ Questions for all Concepts as per the latest syllabus. Practice more on a regular basis with these NEET Biology objective questions on air pollution and improve your subject knowledge & problem-solving skills along with time management. NEET Biology Lac Operon Multiple Choice Questions make you feel confident in answering the question in the exam & increases your scores to high.


Q.1. This will be prevented if the activator fastens to the repressor

(a) Transcription
(b) Binding of the RNA polymerase to the promoter
(c) Binding of the repressor to the operator
(d) Binding of the repressor to the promoter

(c) Binding of the repressor to the operator


Q.2. In Lac-operon, the gene product of LacA gene is

(a) Beta-galactoside permease
(b) Beta-galactoside transacetylase
(c) Beta-galactosidase
(d) Beta-galactoside isomerase

(b) Beta-galactoside transacetylase


Q.3. This condition in lac operon facilitates the condition of lac genes being transcribed at high levels

(a) low glucose, high lactose
(b) low glucose, low lactose
(c) high glucose, high lactose
(d) high glucose, low lactose

(a) low glucose, high lactose


Q.4. The correct option regarding the lac operon in E.coli from the following is

(a) Lac operon is switched on in the absence of lactose
(b) Lac repressor binds to the lac promoter
(c) β-galactosidase is the only enzyme produced in large quantities when lac operon is turned on
(d) lac operon messenger RNA is a polycistronic mRNA

(d) lac operon messenger RNA is a polycistronic mRNA


Q.5. The sequence of the structural genes in the lac operon is

(a) lacA-lacZ-lacY
(b) lacZ-lacY-lacA
(c) lacZ-lacA-lacY
(d) lacA-lacY-lacZ

(b) lacZ-lacY-lacA


Q.6. Regulation of the lac operon can be envisioned as regulation of enzyme synthesis by its

(a) lactose
(b) substrate
(c) carbohydrates
(d) all of the above

(d) all of the above


Q.7. Lac Operon will be turned on when

(a) Lactose is less than glucose
(b) Lactose is less in the medium
(c) Lactose in more than glucose
(d) Glucose is enough in the medium

(c) Lactose in more than glucose


Q.8. Lac operon is an example of

(a) only positive regulation
(b) only negative regulation
(c) both positive and negative regulation
(d) sometimes positive sometimes negative

(c) both positive and negative regulation


Q.9. In the presence of lactose, how long does it take for the lac operon to be expressed?

(a) when lactose equals glucose concentration
(b) when glucose is more than lactose concentration
(c) as long as lactose is more than glucose concentration
(d) as long as lactose is more than galactose concentration

(c) as long as lactose is more than glucose concentration


Q.10. Which of these acts as an inducer of the lac operon?

(a) Allolactose
(b) Lactose
(c) Galactose
(d) Glucose

(a) Allolactose

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