Home
Class 12
BIOLOGY
A low level of expression of lac operon ...

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

Text Solution

Verified by Experts

In the complete absence of expression of lac operon, permease will not be synthesised which is essential for transport of lactose from medium into the cells. And if lactose cannot be transported into the cell. then it cannot act as inducers hence, cannot relieve the lac operon from its repressed state
Promotional Banner

Topper's Solved these Questions

  • GENETICS AND EVOLUTION

    TRUEMEN BIOLOGY ENGLISH|Exercise SECTION-C|45 Videos

  • GENETICS AND EVOLUTION

    TRUEMEN BIOLOGY ENGLISH|Exercise SECTION-D|25 Videos

  • GENETICS AND EVOLUTION

    TRUEMEN BIOLOGY ENGLISH|Exercise SECTION-D|25 Videos

  • Genetics

    TRUEMEN BIOLOGY ENGLISH|Exercise ASSERTION AND REASON|122 Videos

  • HUMAN HEALTH AND DISEASE

    TRUEMEN BIOLOGY ENGLISH|Exercise MULTIPLE CHOICE QUESTIONS|209 Videos

Similar Questions

Explore conceptually related problems

The repressor of the lac operon is synthesised all the time constitutively from the

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

Which of following statement is true for lac operon in E-coli (a) lac operon consists of one regulatory gene and five structural gene. (b) The i gene codes for inducer (c) The z-gene codes for beta -galacosidase (d) A very low level of expression of lac operon has to be present in cell all the time

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 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?

Suppose you are standing on a boat in the middle of a swimming pool. The boat is loaded with a bag of stones. Can you get to the shore using the stones ? If yes, explain the concept behind it.

In eukaryotes, regulation of gene expression can be done at all the following levels, except

TRUEMEN BIOLOGY ENGLISH-GENETICS AND EVOLUTION -SECTION-B
  1. You are repeating the Hershey-Chase experiment and are provided with t...

    Text Solution

    |

  2. There is only one possible sequence of amino acids when deduced from a...

    Text Solution

    |

  3. A low level of expression of lac operon occurs at all the time. Can yo...

    Text Solution

    |

  4. Would it be appropriate to use DNA probes such as VNTR in DNA fingerp...

    Text Solution

    |

  5. During in vitro synthesis of DNA, a researcher used 2. 3' dideoxy cyti...

    Text Solution

    |

  6. What background information did Watson and Crick have made available f...

    Text Solution

    |

  7. What are the functions of (i) methylated guanine cap? (ii) poly...

    Text Solution

    |

  8. Do you think that the alternate splicing of exons may enable a structu...

    Text Solution

    |

  9. Comment on the utility of variability in number of tansem repeats duri...

    Text Solution

    |

  10. Write the full of VNTR. How is VNTR different from 'Probe' ?

    Text Solution

    |

  11. A non-haemophilic couple was infomed by their doctor that there is pos...

    Text Solution

    |

  12. In a particular plant species majority of the plants bear purple flowe...

    Text Solution

    |

  13. A cross between a red flower bearing plant and a white flower bearing ...

    Text Solution

    |

  14. In a typical monohybrid cross the F(2)-population ratio is written as ...

    Text Solution

    |

  15. Work out a cross to find the genotype of a tall pea plant. Name the ty...

    Text Solution

    |

  16. (a) Write the specific features of the genetic code AUG (b) Explain...

    Text Solution

    |

  17. Arrange the following groups of plants in an ascending evolutionary s...

    Text Solution

    |

  18. While creation and presence of variation is directionless, natural sel...

    Text Solution

    |

  19. Gene flow occurs through generations. Gene flow can occur across langu...

    Text Solution

    |

  20. When we say ' survival of the fittest ' , does it mean that (a) tho...

    Text Solution

    |