Self Quiz for Bacterial Genetics: Enzyme Regulation

Study the material in this section and then write out the answers to these question.
Do not just click on the answers and write them out. This will not test your understanding of this tutorial.

1. Matching

_____ Regulatory proteins that block transcription of mRNA by binding to a portion of DNA called the operator that lies downstream of a promoter. (ans)

_____ A molecule that alters the shape of the regulatory protein in a way that blocks its binding to the operator and thus permits transcription. (ans)

_____ Regulatory proteins that promote transcription of mRNA. (ans)

_____ A molecule that alters the shape of the regulatory protein to a form that can bind to the operator and block transcription. (ans)

_____ Producing antisense RNA (def) that is complementary to the mRNA coding for the enzyme. When the antisense RNA binds to the mRNA by complementary base pairing, the mRNA cannot be translated into protein and the enzyme is not made. (ans)

_____ The induction or repression of enzyme synthesis by regulatory proteins that can bind to DNA and either block or enhance the function of RNA polymerase. (ans)

_____ The inhibitor is the end product of a metabolic pathway that is able to bind to a second site (the allosteric site) on an enzyme. Binding of the inhibitor to the allosteric site alters the shape of the enzyme's active site thus preventing binding of the first substrate in the metabolic pathway. (ans)

_____ The inhibitor is the end product of an enzymatic reaction. That end product is also capable of reacting with the enzyme's active site and prevents the enzyme from binding its normal substrate. (ans)

_____Regulatory proteins that bind to DNA located some distance from the operon they control by working with DNA-bending proteins that enable RNA polymerase can to bind to a promoter and initiate transcription. (ans)

A. activators
B. competitive inhibition
C. corepressors
D. genetic control
E. inducer
F. non-competitive inhibition
G. repressors
H. translational control
I. enhancers

2. Describe how the lac operon in E. coli functions as an inducible operon. (ans)

 

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Gary E. Kaiser, Ph.D.
Professor of Microbiology
The Community College of Baltimore County, Catonsville Campus
This work is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work The Grapes of Staph at https://cwoer.ccbcmd.edu/science/microbiology/index_gos.html.

Last updated: August, 2018
Please send comments and inquiries to Dr. Gary Kaiser