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Assertion :- Lactose is the substrate fo...

Assertion :- Lactose is the substrate for the enzyme `beta`-galactosidse & it regulates switching on & off of the operon.
Reson: A very low level of expression of lac operon is always present in cell all the time.

A

If both assertion and reason are true and reason is the correct explanation of assertion.

B

If both assertion and reason are true but reason is not the correct explanation of assertion.

C

If assertion is true but reason is false

D

If both assertion and reason are false.

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The correct Answer is:
B
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Lactose is the substrate for the enzyme beta - galactosidase and it regulates switching on and off of the operon. Hence it is termed as

Assertion (A): Lactose is the substrate for the enzyme beta-galactosidase and it regulates switching on and off of the lac operon. Reason ( R): The lac operon consists of one regulatory gene and three structural genes.

Read the following statements w.r.t. lac operon. Br a. lac-i is the constitutive gene. Br b. lac-y codes for permease to increase permeability of cell to Beta -galactoside. Br c. Lactose is the substrate for the enzyme B- galactosidase and it regulates switching on and off of the operon. br d. Regulation of lac operan can be also visualised as regulation of enzyme synthesis by its substrate.

Why does the lac operon shut down some time after the addition of lactose in the medium where E.coli was growing ? Why low level expression of lac operon is always required ?

A low level of expression of lac operon occurs at all the time. Can you explain the logic behind this phenomena.

Read the statements regarding the lac operon and choose the correct option. 1. An inducer regulates the switching on and off of lac operon. 2. Repressor protein dissociates from operator region and prevents RNA polymerase from transcribing the operon. 3. In the presence of lactose, the repressor is activated by interaction with lactose. 4. RNA polymerase has access to the promoter and transcription proceeds only when the repressor is inactivated.

Read the following statements for lac operon: i. Each operon has its specific operator and specific repressor. ii. The y gene codes permease, which increases the permeability of the cell to beta-galactosides. iii. Regulation of lac operon can be visualized as regulation of enzyme synthesis by its substrate. Select the option with the correct statements.

MOTION-MOLECULAR BASIS OF INHERITANCE-EXERCISE - 4 (ASSERTION & REASON)
  1. Assertion :- t RNAs are specific for each amino acid but there are no ...

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  2. Assertion :- Inhibition of transcription is the only method of regula...

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  3. Assertion :- In lac operon, a polycistronic structural gene is regulat...

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  4. Assertion :- The gene I codes for the repressor of the lac operon. R...

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  5. Assertion :- Lactose is the substrate for the enzyme beta-galactosidse...

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  6. Assertion :- Inhibition of transcription is the only method of regula...

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  7. Assertion :- Lac opertor is present only in lac operon & it interact s...

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  8. Assertion :- Gene regulation in prokaryotes is comparatively simple th...

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  9. Assertion :- In lac operon, a polycistronic structural gene is regulat...

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  10. Assertion :- The gene I codes for the repressor of the lac operon. R...

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  11. Assertion :- Lactose is the substrate for the enzyme beta-galactosidse...

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  12. Assertion :- Regulation of lac opernon by repressor is referred to as ...

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  13. Assertion :- HGP was closely associated with the rapid development of ...

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  14. Assertion :-BAC & YAC are the common vectors used in HGP. Reason : I...

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  15. Assertion :- DNA fingerprinting is a very quick way to compare the DNA...

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  16. Assertion :- The repetitive DNA are separted from bulk genomic DNA as ...

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  17. Assertion :- DNA fingerprinting involves identifying differences in so...

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  18. Assertion :- The probability of DNA polymorphism would be higher in no...

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  19. Assertion :- The VNTR belongs to a class of satellite DNA referred to...

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  20. Assertion :- The senstivity of fingerprinting technique has been incre...

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