WorksheetsAP BIO - Prokaryotic Gene Regulation
Total questions: 10
Worksheet time: 9mins
What is NOT an accurate difference between the organization of prokaryotic genomes vs. eukaryotic genomes?
Prokaryotes possess a single circular chromosome whereas eukaryotes possess multiple linear chromosomes
Prokaryotes do not organize their DNA around histones, while eukaryotes do
Prokaryotes can have plasmids while eukaryotes cannot
Prokaryotic genomes contain operons whereas eukaryotic genomes do not
A cluster of genes in a prokaryote that code for proteins all performing related functions in the cell is called a...
Regulatory Sequence
Distal Control Element
Open Reading Frame (ORF)
Operon
An operon is best defined as...
transcription and translation happening simultaneously
a group of genes that share the same operator and promoter in a prokaryote
polycistronic mRNA
a gene that requires activation by a transcription factor to be expressed.
A structural gene...
turns other genes on or off
codes for proteins to be translated in the cell
is a sequence of nucleotides where regulatory proteins bind
codes for cell parts that provide rigidity to the cell
A researcher is studying a particular operon and notices that under very specific environmental conditions, the repressor is bound to the operator. The most reasonable conclusion is that...
the environment dictates that the structural genes within the operon should not be transcribed
the regulatory gene coding for the repressor protein must contain a mutation
the operon is an inducible system
the structural genes within the operon must not be essential for the bacterium's survival
If a researcher studying an inducible operon system in a particular strain of bacteria suspects that the operator sequence might have experienced a loss-of-function mutation, what experiment would provide evidence to support the hypothesis?
Artificially synthesize proteins using the structural genes of another population of similar bacteria and then insert these into the cell. Observe whether the operon turns off in response.
Use restriction (cutting) enzymes to cut out the operator and see if the operon regains function.
Induce a mutation in the promoter sequence as well and observe whether the structural genes can be transcribed.
Bioengineer a plasmid containing an unmutated copy of the operator and insert it into a bacterium. Ensure there are no inducers in the cell and observe whether a repressor binds the operator.
What is true about this operon?
The regulatory gene codes for protein A.
RNA polymerase binds to a sequences of nitrogen bases called the operator.
Four RNA polymerases are required to work on this operon --- one for each structural gene.
The mRNA transcribed is polycistronic (containing nucleotide sequences containing multiple start/stop codons and coding for more than one protein)
What DNA base sequence in an operons is responsible for holding the genetic information for the making of the operon repressor
Regulatory Gene
Promoter
Operator
First Structural Gene
Reorder the following steps to illustrate how an inducible operon system is turned on.
RNA polymerase binds the promoter and the inducer binds the repressor, which unbinds from the operator.
RNA proceeds past the operator and moves along the structural genes transcribing mRNA.
A polycistronic mRNA is produced at the end of transcription.
Multiple ribosomes work on the mRNA strand to translate the structural proteins.
The newly synthesized proteins carry out a related function in the cell.
Match the following.
Is normally "off" but can be turned "on".
Turned on by the presence of an INDUCER.
Allows for the synthesis of enzymes only when needed.
Example includes the lac operon.
The operator is usually bound by the repressor.
Can be activated by small molecules that interact with the repressor.
Facilitates the breakdown of lactose when it is present.
Is normally "on" but can be turned "off".
Regulates the synthesis of enzymes continuously unless a corepressor is present.
The operator is usually free of the repressor.
Turned off by the build up of a COREPRESSOR.
