BIOL 2500 chapter 14 mc

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

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 conc of the final product is high enough, it binds to a regulatory site o 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

allosteric enzyme

what would be the result if the U-rich sequence after the fourth 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

operator

cis-acting element

tryptophan

co repressor

allolactose

co-repressor

in jacob, monod, and pardee's experiment, what would have been the conclusion if all four tubes produced a yellow color when b-ONPG was added

expression of the lac operon is constitutive whether lacI is functional or not

DNA that contains instructions for two or more structural genes produces monocistronic mRNA

false

a riboswitch only affects translation of an operon

false

in the lac operon, the operator is an example of a trans-effect genetic regulation

false

in the lac operon, the operator site is recognized by an activator protein

false

negative transcriptional regulation is conducted by activator proteins

false

operons that code for anabolic enzyme systems are typically regulated by inducers

false

operons that code for catabolic enzyme systems are typically regulated by repressors

false

enzymes involved in metabolism are most likely regulated via

feedback inhibition

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

lac operon

inducible

which of the following encode polycistronic mRNA?

lac operon, trp operon

translational regulatory proteins recognize specific areas of what molecule

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 abscence of lactose?

no transcription

which of the following is an example of post-translational regulation in prokaryotes?

phosphorylation of an enzyme

an activator is present and results in the increase in transcription of the target gene. this is an example of

positive control

regulation of gene expression may occur at which of the following levels?

post translation, translation, transcription

the regulation of protein function is called

posttranslational 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 ___.

promoter, low

trp operon

repressible

a gene is inducible and under negative control. which of the following pairs will allow expression of this gene?

repressor and 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

lacI gene product

trans-acting element

if CAP could not bind to its CAP site, then what would be the result? assume lactose is present

transcription would be difficult to activate in the absence of glucose

what is the gene responsible for attenuation in the trp operon

trpL

constitutive genes are those that have constant levels of expression

true

repressor proteins are responsible for negative transcriptional regulation

true

the form of regulation that involves a physical change in the shape of an enzyme is called allosteric regulation

true

the regulation of the CAP complex using cAMP is an example of inducible genetic regulation

true

the term enzyme adaptation is used to describe an enzyme that appears in a living cell following exposure to a specific substrate

true

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