BIOL 191 FINAL EXAM FALL 2024 AMHERST COLLEGE
UPDATED QUESTIONS AND VERIFIED ANSWERS
What is constitutive? - CORRECT ANSWER✅✅✅Gene is not regulated, so expression is constant
What is regulated genes? - CORRECT ANSWER✅✅✅Gene can be shut on/off and
increased/decreased as a response to some cue
Why regulate gene expression? (4) - CORRECT ANSWER✅✅✅for efficiency and to respond to
environmental/physiological changes. Morre importantly, for cell specialization and to account for
changes over the course of development.
In which processes can you regulate gene expression? (4) - CORRECT ANSWER✅✅✅transcription,
RNA processing, translation, and post-translational modification.
what are the three tricks that are fundamental to transcription regulation? - CORRECT
ANSWER✅✅✅1. proteins bind to a specific part of DNA molecule, 2) proteins can change
confirmation, and 3) promoters can be regulated such that the frequency of transcription
increases/decreases
Explain the model system of E.coli - CORRECT ANSWER✅✅✅cleave lactose into glucose when
glucose is absent in the environment by making three enzymes: beta-galactosidase, lactose permease,
and transacetylase.
how are these three enzymes regulated by lactose? - CORRECT ANSWER✅✅✅the presence of
lactose increases gene expression of these three enzymes. lactose binding to repressor causes repressor
to release so that the three genes can be transcribed. in the absence of lactose, the repressor binds to
the operator and blocks transcription. thus, lactose induces gene transcription
How do proteins bind to DNA in a specific manner? - CORRECT ANSWER✅✅✅reach into major and
minor grooves and make non-covalent bonds with the base pairs. alpha helix specifically fits in major
groove of DNA.
, what is allosteric regulation? - CORRECT ANSWER✅✅✅regulation of a process through the changing
of shape of a target protein by the a ligand (small molecule).
what makes a promoter weak versus strong? - CORRECT ANSWER✅✅✅the frequency with which it
binds to RNA polymerase.
what can change a promoter's strength? - CORRECT ANSWER✅✅✅regulatory proteins.
what is a positive regulatory protein? - CORRECT ANSWER✅✅✅a protein which increases the rate of
transcription. this is activation of the promoter.
what is a negative regulatory prtein? - CORRECT ANSWER✅✅✅a protein which decreases or stops
the rate of transcription. this is repression of the promoter.
explain genetic regulation in the trp operon pathway - CORRECT ANSWER✅✅✅repressor protein
binds to operon when trp is present. when trp is absent, the repressor protein comes off of the operon
and the genes for trp synthesis are transcribed. trp allosterically regulates the repressor protein to bind
and unbind it from DNA. this is negative feedback regulation
what is negative feedback regulation? - CORRECT ANSWER✅✅✅when the product of the pathway
turns off the pathway.
what is gene regulation? - CORRECT ANSWER✅✅✅what allows cells to only use the genes it needs.
selects for certain genes to be expressed to fit current needs.
what is cell specialization? - CORRECT ANSWER✅✅✅the process in which cells develop in different
ways to perform different tasks
what makes regulation of eukaryotic genes different from regulation of prokaryotic genes? - CORRECT
ANSWER✅✅✅prokaryoktic genes are organized into operons, whereas eukarotic genes are not. this
is because of introns and exons. this difference makes it such that regulatory proteins can be 1000s of
nucleotides upstream of the promoter.
UPDATED QUESTIONS AND VERIFIED ANSWERS
What is constitutive? - CORRECT ANSWER✅✅✅Gene is not regulated, so expression is constant
What is regulated genes? - CORRECT ANSWER✅✅✅Gene can be shut on/off and
increased/decreased as a response to some cue
Why regulate gene expression? (4) - CORRECT ANSWER✅✅✅for efficiency and to respond to
environmental/physiological changes. Morre importantly, for cell specialization and to account for
changes over the course of development.
In which processes can you regulate gene expression? (4) - CORRECT ANSWER✅✅✅transcription,
RNA processing, translation, and post-translational modification.
what are the three tricks that are fundamental to transcription regulation? - CORRECT
ANSWER✅✅✅1. proteins bind to a specific part of DNA molecule, 2) proteins can change
confirmation, and 3) promoters can be regulated such that the frequency of transcription
increases/decreases
Explain the model system of E.coli - CORRECT ANSWER✅✅✅cleave lactose into glucose when
glucose is absent in the environment by making three enzymes: beta-galactosidase, lactose permease,
and transacetylase.
how are these three enzymes regulated by lactose? - CORRECT ANSWER✅✅✅the presence of
lactose increases gene expression of these three enzymes. lactose binding to repressor causes repressor
to release so that the three genes can be transcribed. in the absence of lactose, the repressor binds to
the operator and blocks transcription. thus, lactose induces gene transcription
How do proteins bind to DNA in a specific manner? - CORRECT ANSWER✅✅✅reach into major and
minor grooves and make non-covalent bonds with the base pairs. alpha helix specifically fits in major
groove of DNA.
, what is allosteric regulation? - CORRECT ANSWER✅✅✅regulation of a process through the changing
of shape of a target protein by the a ligand (small molecule).
what makes a promoter weak versus strong? - CORRECT ANSWER✅✅✅the frequency with which it
binds to RNA polymerase.
what can change a promoter's strength? - CORRECT ANSWER✅✅✅regulatory proteins.
what is a positive regulatory protein? - CORRECT ANSWER✅✅✅a protein which increases the rate of
transcription. this is activation of the promoter.
what is a negative regulatory prtein? - CORRECT ANSWER✅✅✅a protein which decreases or stops
the rate of transcription. this is repression of the promoter.
explain genetic regulation in the trp operon pathway - CORRECT ANSWER✅✅✅repressor protein
binds to operon when trp is present. when trp is absent, the repressor protein comes off of the operon
and the genes for trp synthesis are transcribed. trp allosterically regulates the repressor protein to bind
and unbind it from DNA. this is negative feedback regulation
what is negative feedback regulation? - CORRECT ANSWER✅✅✅when the product of the pathway
turns off the pathway.
what is gene regulation? - CORRECT ANSWER✅✅✅what allows cells to only use the genes it needs.
selects for certain genes to be expressed to fit current needs.
what is cell specialization? - CORRECT ANSWER✅✅✅the process in which cells develop in different
ways to perform different tasks
what makes regulation of eukaryotic genes different from regulation of prokaryotic genes? - CORRECT
ANSWER✅✅✅prokaryoktic genes are organized into operons, whereas eukarotic genes are not. this
is because of introns and exons. this difference makes it such that regulatory proteins can be 1000s of
nucleotides upstream of the promoter.
