BIO230 Exam 2026 Questions and
Answers
Transcriptome - Correct answer-The repetoire of all RNA in a cell at a time.
DNA Microarray - Correct answer-Shows DNA fragments representing all genes
with fluoresence representing the degree of expression
Proteome - Correct answer-All cellular protein-maintained by translation.
Prokaryotic Transcription (sigma factor, RNAp holoenzyme) - Correct answer-The
sigma factor helps RNA polymerase bind to the promoter. the DNA is bound and
when 10 nucleotides are synthesized the sigma factor is released for elongation and
termination to occur.
Gene regulatory proteins - Correct answer-AKA transcription factors, they bind to
Cis elements as activators or repressors.
Tryp operon - Correct answer-Makes sure that tryp is produced onl when it is
scarce. RNAP + sigma factors bind to the operator to turn it on, while tryp
regulatory protein turnsif off. It has a helix-turnhelix motif. Tryp induced
conformational changes allow the helixi-turn helix to fit in the DNA major grove.
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,Lac Operon - Correct answer-It creates beta-galactosidase to break down lactose
into glucose and galactose. Has dual regulation. When lactose is high and glucose
is low it is promoted by CAP. When lactose is low, it is repressed by the lac
repressor protein. When lactose levels increase, allolactose levels increase and bind
to the lac repressor, causing a conf. change releasing it and decreasing its binding
activity. When glucose levels are low, cAMP levels increase. cAMP binds to CAP,
pushes the CAP helix-turn-helix to bind to DNA making RNA P bining more
efficient.
Positive Transcriptional Regulation - Correct answer-Activator protein recruits
RNAP
Negative Transcriptional Regulation - Correct answer-RNAP and repressor
compete for binding. These elements are often found right before the promoter, but
can be found anywhere else (in eukaryotes they are sometimes downstream or
internal).
DNA looping - Correct answer-Cis elements far away from a start site play a
regulatory role eg the lac repressor 2*2 tetramer.
Bacteriophage lambda life cycle - Correct answer-Prophage Pathway-Join bacterial
DNA and reproduce with it. The lambda repressor represses cro protein, promotoes
lambda synthesis and represses its own transcription.
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, Lytic Pathway (unfavorable conditions)-form new viruses and break out. Cro
represses lambda and primarily transcribes itself. The cro repressor protein is a flip
flop device turning off cro and promoting itself in good conditions.
Repressillator - Correct answer-Synthetic gene ossilator: a represses b, promoting c
turning off a.
Transcription Attenuation - Correct answer-in prokaryotes transcription &
translation occur simultaneously, attenuation occurs when rapid translation of new
transcript causes premature termination of transcription. Regulatory proteins can
prevent it.
Riboswitches - Correct answer-Short RNA sequences that change conformation
when bound by small molecules eg guanine vi riboswitch-when guanine levels are
high, they bind the riboswitch, conformation changes and transcription is
terminated.
RNAPI - Correct answer-Transcribes 5.8s, 18s and 28s rrna GENES.
RNAPII - Correct answer-Transcribes all protein-coding genes, snoRNA genes,
miRNA genes, siRNA genes and most snRNA genes.
RNA PIII - Correct answer-Transcribes tRNA genes, 5SrRNA genes, some snRNA
genes and genes for other small RNAs..
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Answers
Transcriptome - Correct answer-The repetoire of all RNA in a cell at a time.
DNA Microarray - Correct answer-Shows DNA fragments representing all genes
with fluoresence representing the degree of expression
Proteome - Correct answer-All cellular protein-maintained by translation.
Prokaryotic Transcription (sigma factor, RNAp holoenzyme) - Correct answer-The
sigma factor helps RNA polymerase bind to the promoter. the DNA is bound and
when 10 nucleotides are synthesized the sigma factor is released for elongation and
termination to occur.
Gene regulatory proteins - Correct answer-AKA transcription factors, they bind to
Cis elements as activators or repressors.
Tryp operon - Correct answer-Makes sure that tryp is produced onl when it is
scarce. RNAP + sigma factors bind to the operator to turn it on, while tryp
regulatory protein turnsif off. It has a helix-turnhelix motif. Tryp induced
conformational changes allow the helixi-turn helix to fit in the DNA major grove.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
,Lac Operon - Correct answer-It creates beta-galactosidase to break down lactose
into glucose and galactose. Has dual regulation. When lactose is high and glucose
is low it is promoted by CAP. When lactose is low, it is repressed by the lac
repressor protein. When lactose levels increase, allolactose levels increase and bind
to the lac repressor, causing a conf. change releasing it and decreasing its binding
activity. When glucose levels are low, cAMP levels increase. cAMP binds to CAP,
pushes the CAP helix-turn-helix to bind to DNA making RNA P bining more
efficient.
Positive Transcriptional Regulation - Correct answer-Activator protein recruits
RNAP
Negative Transcriptional Regulation - Correct answer-RNAP and repressor
compete for binding. These elements are often found right before the promoter, but
can be found anywhere else (in eukaryotes they are sometimes downstream or
internal).
DNA looping - Correct answer-Cis elements far away from a start site play a
regulatory role eg the lac repressor 2*2 tetramer.
Bacteriophage lambda life cycle - Correct answer-Prophage Pathway-Join bacterial
DNA and reproduce with it. The lambda repressor represses cro protein, promotoes
lambda synthesis and represses its own transcription.
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
, Lytic Pathway (unfavorable conditions)-form new viruses and break out. Cro
represses lambda and primarily transcribes itself. The cro repressor protein is a flip
flop device turning off cro and promoting itself in good conditions.
Repressillator - Correct answer-Synthetic gene ossilator: a represses b, promoting c
turning off a.
Transcription Attenuation - Correct answer-in prokaryotes transcription &
translation occur simultaneously, attenuation occurs when rapid translation of new
transcript causes premature termination of transcription. Regulatory proteins can
prevent it.
Riboswitches - Correct answer-Short RNA sequences that change conformation
when bound by small molecules eg guanine vi riboswitch-when guanine levels are
high, they bind the riboswitch, conformation changes and transcription is
terminated.
RNAPI - Correct answer-Transcribes 5.8s, 18s and 28s rrna GENES.
RNAPII - Correct answer-Transcribes all protein-coding genes, snoRNA genes,
miRNA genes, siRNA genes and most snRNA genes.
RNA PIII - Correct answer-Transcribes tRNA genes, 5SrRNA genes, some snRNA
genes and genes for other small RNAs..
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