Genetics Chpt 14
Regulation of gene expression may occur at which of the following levels? Check all that apply. Select one or more: A) post translation B) constitutive expression C) translation D) transcription
A) post translation C) translation D) transcription
How many promoters are in an operon? Select one: A. 1 B. 2 C. 3 D. It depends on how many genes are present in the operon
A. 1
If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario. Select one: A. Transcription would be difficult to activate in the absence of glucose B. Transcription would be difficult to activate in the presence of glucose C. Transcription would be difficult to repress in the presence of glucose
A. Transcription would be difficult to activate in the absence of glucose
The regulation of a protein's ability to function is called ________. Select one: A. post-translational regulation B. post-transcriptional regulation C. translational regulation D. transcriptional regulation
A. post-translational regulation
In the lac operon, the CAP site is located next to the ________. When both lactose and glucose are present, this leads to a rate of transcription that is ________. Select one: A. terminator, high B. promoter, low C. promoter, high D. terminator, low
B. promoter, low
If a bacteria is placed in an environment that contains both glucose and lactose, the regulation of the lac operon will allow which nutrient to be processed first? Select one: A. Both will be processed equally B. Neither will be processed in this environment C. Glucose D. Lactose
C. Glucose
Allosteric regulation is accomplished by Select one: A. a large protein that blocks an enzyme's active site. B. a small molecule that covalently modifies a site on the enzyme that is not the active site. C. a small molecule that fits into a site on the enzyme that is not the active site. D. a small molecule that fits into an enzyme's active site.
C. a small molecule that fits into a site on the enzyme that is not the active site.
Enzymes involved in metabolic pathways are most likely regulated via ________. Select one: A. methylation B. acetylation C. feedback inhibition D. none of the answers are correct
C. feedback inhibition
Translational regulatory process such as antisense RNA recognize specific areas of what molecule? Select one: A. rRNA B. tRNA C. mRNA D. ribosome
C. mRNA
A mutation in the lacI gene prevents the gene product from binding allolactose. What will the expression level of the operon be in the absence of lactose? Select one: A. positive regulation B. periodic expression C. no transcription D. constitutively active
C. no transcription
Antisense RNA does which of the following? Select one: A. Inhibits the formation of the open complex in transcription B. Prevents the correct folding of a newly formed peptide C. Occupies the A and P sites of the ribosome D. Binds to the mRNA and prevents translation
D. Binds to the mRNA and prevents translation
Which of the following is an example of post translational regulation in prokaryotes? Select one: A. Antisense RNA binding to the mRNA B. Altering the structure of the mRNA (e.g., alternative splicing) C. Blocking the ribosome from binding to the mRNA D. Phosphorylation of an enzyme with a protein kinase
D. Phosphorylation of an enzyme with a protein kinase
A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene? Select one: A. Repressor + co-repressor B. Activator + repressor C. Activator + inhibitor D. Repressor + inducer
D. Repressor + inducer
A deletion in an operon removes the terminator. How will that affect the transcript that is produced from the operon? Select one: A. The transcript will be produced and normal in length B. The transcript will produced, but will contain a deletion C. The transcript will be produced, but shorter than normal D. The transcript will be produced, but longer than normal E. The transcript will not be produced
D. The transcript will be produced, but longer than normal
A deletion in an operon removes the promoter. How will that affect the transcript that is produced from the operon? Select one: A. The transcript will produced, but will contain a deletion B. The transcript will be produced and normal in length C. The transcript will be produced, but shorter than normal D. The transcript will not be produced E. The transcript will be produced, but longer than normal
D. The transcript will not be produced
An enzyme catalyzes a substrate into a final product. When the concentration of the final product is high enough, it binds to a regulatory site on the enzyme. This binding at the regulatory site changes the shape of the enzyme, which prevents it from binding the substrate and prevents formation of more final product. This is an example of a(n) ________. Select one: A. translational repressor B. posttranslational modification C. methylation D. allosteric enzyme
D. allosteric enzyme
An activator is present and results in the increase in transcription of the target gene. This is an example of ________. Select one: A. feedback inhibition B. negative control C. termination D. positive control
D. positive control
[T/F] DNA that contains instructions for two or more structural genes produces monocistronic mRNA.
False
[T/F] In the lac operon, the operator site is recognized by an activator protein.
False
[T/F] Negative transcriptional regulation is conducted by activator proteins.
False
In the absence of glucose, cAMP binds to CAP, which allows CAP to bind to the activator region and transcription is activated in the presence of lactose. Is this a TRUE or FALSE statement. The regulation of the CAP using cAMP is an example of inducible genetic regulation
True
[T/F] Constitutive genes are those that have constant levels of expression.
True
[T/F] One reason genes are regulated is because it is an energy-savings system. It is wasteful to make proteins and other nutrients if they aren't needed.
True
[T/F] Regulated genes have variable levels of gene expression, while constitutive genes are transcribed at constant levels of expression.
True
[T/F] Repressor proteins are responsible for negative transcriptional regulation.
True
[T/F] The form of regulation that involves a physical change in the shape of an enzyme is called allosteric regulation.
True
Match the two groups to their correct pairings 1. Co-repressor 2. Inducible 3. Inducer 4. Repressible a. Lac operon b. Alloactose c. Trp operon d. Tryptophan
~ Co-repressor - Tryptophan ~ Inducible - Lac operon ~ Inducer - Allolactose ~ Repressible - Trp operon