Chapter 14 Genetics Study Guide Questions
The regulation of protein function is called __________.
posttranslational regulation
How many promoters are in an operon?
1
In Jacob, Monod, and Pardee's experiment, how many functional copies of lacI were there in the merozygote?
1
What stem-loop conformations favor attenuation?
1-2 and 3-4
What would be the result if the U-rich sequence after the 3/4 stem-loop in the trp operon was replaced by a UG-rich sequence?
Attenuation would not occur if tryptophan was high
Antisense RNA does which of the following?
Binds to the mRNA and prevents translation
In Jacob, Monod, and Pardee's experiment, what would have been the conclusion of all four tubes producing a yellow color when b-ONPG was added?
Expression of the lac operon is constitutive whetherlacIis functional or not
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?
Glucose
You are studying riboswitches in different bacterial strains and you mix up two of your samples! One sample is from E. coli and the other is from B. subtilis. You have an assay in the lab that allows you measure the levels of the enzymes encoded by the thi/thiMD operon (assume the enzymes from the two organisms are similar). Would this assay allow you to distinguish between the two strains?
No - it would be difficult to distinguish between the strains using this assay.
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?
No transcription
Which of the following is an example of post-translational regulation in prokaryotes?
Phosphorylation of an enzyme
Regulation of gene expression may occur at which of the following levels? (Check all that apply.) A)Post translation B)Constitutive expression C)Translation D)Transcription
Posttranslation Constitutive expression Translation
A gene is inducible and under negative control. Which of the following pairs will allow the expression of this gene?
Repressor + inducer
A deletion in an operon removes the terminator. How will that affect the transcript that is produced from the operon?
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?
The transcript will not be produced
If the Trp codons in the trpL gene were mutated to encode another amino acid, what would the result be?
The trp operon would never be transcribed.
If CAP could not bind to its CAP site, then what would be the result? Assume lactose is present in each scenario.
Transcription would be difficult to activate in the absence of glucose
In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated?
Two
Allosteric regulation is accomplished by __________.
a small molecule that fits into a site on the enzyme that is not the active site
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/an __________.
allosteric enzyme
Enzymes involved in metabolism are most likely regulated via __________.
feedback inhibition
Translational regulatory proteins recognize specific areas of what molecule?
mRNA
An activator is present and results in the increase in transcription of the target gene. This is an example of _______________.
positive control
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 __________.
promoter; low
What is the gene responsible for attenuation in the trp operon?
trpL
