Answer to Question #59107 in Cell Biology for Tracy Guido

Question

59. Arrange the following steps of the regulation of the trp operon in order of occurrence.
1. Rna polymerase binds to the promoter, allowing transcription of the trp genes to proceed. 2. Enzymes produced from the trp genes catalyze tryptophan production 3. sufficient quantities of tryptophan make further synthesis unnecessary. 4. Tryptophan activates the trp repressor protein. 5. the trp repressor protein binds to the operator. 6. the trp repressor protein blocks RNA polymerase from binding to the promoter.


60.
An operon is a group of genes under the control of a single promoter. Match each type of operon with the descriptions below.
Inducible repressible constitutive
A. under default conditions, transcription is inhibited. b. activating the repressor gene product inhibits transcription. c. the amount of gene product is constant d. Sufficient amounts of the gene product inhibit further transcription

Answer 1

59. 1. Rna polymerase binds to the promoter, allowing transcription of the trp genes to proceed. 2. Enzymes produced from the trp genes catalyze tryptophan production 3. sufficient quantities of tryptophan make further synthesis unnecessary. 4. Tryptophan activates the trp repressor protein.5. the trp repressor protein binds to the operator. 6. the trp repressor protein blocks RNA polymerase from binding to the promoter. The correct sequence coincides with the given sequence.
60. Inducible A. under default conditions, transcription is inhibited (it starts only when specific inducer is added).
Repressible b. activating the repressor gene product inhibits transcription. (repression occurs by gene product) d. Sufficient amounts of the gene product inhibit further transcription (because it activates the repressor)
Constitutive c. the amount of gene product is constant (always expressed)