ASU BIO 340 Exam 3 Questions with
Verified Answers
lac operon - ✔✔A set of genes and their regulatory elements involved in lactose metabolism in
bacteria.
transcription of the lac operon - ✔✔The process of synthesizing RNA from the lac operon
genes, which is influenced by the presence of lactose and glucose.
allolactose - ✔✔An isomer of lactose that acts as an inducer for the lac operon by binding to
the lac repressor.
CAP (catabolite activator protein) - ✔✔A protein that enhances transcription of the lac operon
when glucose levels are low.
operator mutation - ✔✔A change in the DNA sequence of the operator that affects the binding
of the lac repressor.
lac repressor - ✔✔A protein that binds to the operator to prevent transcription of the lac
operon when lactose is absent.
permease - ✔✔A protein encoded by the lacY gene that facilitates the transport of lactose into
the bacterial cell.
beta-galactosidase - ✔✔An enzyme encoded by the lacZ gene that breaks down lactose into
glucose and galactose.
effector - ✔✔A molecule that influences the activity of a protein, often involved in positive
regulation.
, inducer - ✔✔A molecule that initiates transcription by disabling the repressor.
co-repressor - ✔✔A molecule that binds to a repressor to enable it to bind to the operator and
inhibit transcription.
negative regulation - ✔✔A mechanism that decreases gene expression by inhibiting
transcription.
positive regulation - ✔✔A mechanism that increases gene expression by promoting
transcription.
super repressor - ✔✔A mutated form of the lac repressor that cannot bind allolactose and thus
prevents transcription.
core promoter - ✔✔The region of DNA where RNA polymerase binds to initiate transcription.
enhancers - ✔✔Regulatory sequences that can be located far from the genes they regulate and
enhance transcription.
chromatin remodeling complex - ✔✔A protein complex that alters the structure of chromatin
to allow access to DNA for transcription.
acetylation of histone tails - ✔✔A modification that loosens the interaction between DNA and
histones, facilitating transcription.
repressor binding to operator - ✔✔A mechanism not found in eukaryotes where a repressor
binds to a specific DNA sequence to inhibit transcription.
Verified Answers
lac operon - ✔✔A set of genes and their regulatory elements involved in lactose metabolism in
bacteria.
transcription of the lac operon - ✔✔The process of synthesizing RNA from the lac operon
genes, which is influenced by the presence of lactose and glucose.
allolactose - ✔✔An isomer of lactose that acts as an inducer for the lac operon by binding to
the lac repressor.
CAP (catabolite activator protein) - ✔✔A protein that enhances transcription of the lac operon
when glucose levels are low.
operator mutation - ✔✔A change in the DNA sequence of the operator that affects the binding
of the lac repressor.
lac repressor - ✔✔A protein that binds to the operator to prevent transcription of the lac
operon when lactose is absent.
permease - ✔✔A protein encoded by the lacY gene that facilitates the transport of lactose into
the bacterial cell.
beta-galactosidase - ✔✔An enzyme encoded by the lacZ gene that breaks down lactose into
glucose and galactose.
effector - ✔✔A molecule that influences the activity of a protein, often involved in positive
regulation.
, inducer - ✔✔A molecule that initiates transcription by disabling the repressor.
co-repressor - ✔✔A molecule that binds to a repressor to enable it to bind to the operator and
inhibit transcription.
negative regulation - ✔✔A mechanism that decreases gene expression by inhibiting
transcription.
positive regulation - ✔✔A mechanism that increases gene expression by promoting
transcription.
super repressor - ✔✔A mutated form of the lac repressor that cannot bind allolactose and thus
prevents transcription.
core promoter - ✔✔The region of DNA where RNA polymerase binds to initiate transcription.
enhancers - ✔✔Regulatory sequences that can be located far from the genes they regulate and
enhance transcription.
chromatin remodeling complex - ✔✔A protein complex that alters the structure of chromatin
to allow access to DNA for transcription.
acetylation of histone tails - ✔✔A modification that loosens the interaction between DNA and
histones, facilitating transcription.
repressor binding to operator - ✔✔A mechanism not found in eukaryotes where a repressor
binds to a specific DNA sequence to inhibit transcription.
