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E. colicells with a mutated z gene of th...

E. colicells with a mutated z gene of the lac operon cannot grow in medium containing only lactose as the source of energy because

A

they cannot synthesize functional betagalactosidse

B

They cannot transport lactose from the medium into the cell

C

The lac operon is constitutively active in these cells

D

In the presence of glucose, E. coli cells do not utilize lactose

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The correct Answer is:
A
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In the medium where E. coli was growing, lactose was added, which induced the lac operon. Then, why does lac operon shut down some time after addition of lactose in the medium?

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Gene regulation governing lactose operon of E. coli that involves the lac I gene product is

Gene regulation governing lactose operon of E. coli that involves the lac I gene product is

Select the two correct statements out of the four (1-4) given below about lac operon. 1. Glucose or galactose may bind with the repressor and inactivate it 2. In the absence of lactose the repressor binds with the operator region 3. The z-gene codes for permease 4. This was elucidated Francois Jacob and Jacque Monod The correct statements are :

Go though the following statements (i) Meselson & stahl used cesium chloride density gradient to distinguish heavy DNA molecules from the normal DNA molecules. (ii) In meselson & Stahl experiment the DNA that was extracted from the culture one generation after the transfer from .^(15)N to .^(14)N , was composed of equal amount of hybrid (intermediate) DNA and of light DNA. (iii) In prokaryotes, control f the rate of transcriptional initiation is the predominant site for control of gene expression. (iv) In lac operon, the repressor is synthesised only at the time when the level of metabolite is in excess. Find out the correct statements?

TRUEMAN BIOLOGY-MOLECULAR BASIS OF INHERITANCE-MCQs
  1. The technique used for analysis of RNA is called

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  2. Which of the following statements is not true for retroviruses?

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  3. E. colicells with a mutated z gene of the lac operon cannot grow in me...

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  4. Telomerase is an enzyme which is a

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  5. Which one of the following correctly represents the manner of replicat...

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  6. Which of the following is not true for operon concept of jacob and mon...

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  7. A regularity gene produces some kind of protein through its m-RNA that...

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  8. How many high-energy phosphate bond equivalents are utilized in the pr...

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  9. Given a hypothetical segment of functional DNA strand 3'-GGC AAC CTT G...

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  10. Consider the following events in DNA replication 1. Formation of RNA...

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  11. Which of the following statements are true of all t-RNAs? 1. The 5'e...

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  12. Consider the following processes 1. Synthesis of t-RNA 2. Attachme...

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  13. Match list-I (factos/enzyme) with list-II (activities) and slect the c...

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  14. Which one of the following subprocesses does not take plaec during pro...

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  15. Satellite DNA is important because it

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  16. Which of the following components is required for the proper function ...

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  17. Which of the following blotting methods involves the transferring of p...

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  18. Protein translation proceeds as an ordered process and involves all of...

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  19. Many antibiotics inhibit prokaryotic translation without disrupting pr...

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  20. Replication and transcription are similar processes in mechanistic ter...

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