Gene Expression

  1. In what stage is the predominant level of regulation found in prokaryotes?
  2. What is an inducible enzyme system?
    An enzyme system under the control of an inducer, a regulatory molecule that acts to block a repressor and allow transription.
  3. What is an inducer?
    An effector molecule that activates transcription.
  4. What are constituative enzymes?
    Enzymes that are produce continuously, regardless of the chemical makeup of the environment.
  5. What is a repressible enzyme system?
    An enzyme or group of enzymes whose synthesis is regulated by the intracellular concentration of certain meabolites.
  6. What is the result of a negative control for regulation?
    Gene expression occurs unless it is shut off by some form of a regulator molecule.
  7. What is the result of a positive control for regulation?
    Transcription occurs only if a regulator molecule directly stimulates RNA production.
  8. What is the name of the regulatory region upstream from of the gene it controls?
    cis-acting site in which it is determined whether genes are trancribed into RNA.
  9. What are the three structural genes in the lac operon and what are their purposes?
    • LacZ encodes Bgalactosidase (which cleaves and converts lactose into glucose and galactose).
    • LacY encodes the amino acid sequence of permease (which facilitates the entry of lactose into the cell).
    • LacA codes for the enzyme transacetylase.
Card Set
Gene Expression
The processes of regulating genes