PROKARYOTIC GENE EXPRESSION Flashcards
which genes encode protein invoved in metabolism, biosynthesis or cell structure
Structural genes
which genes encode products that interact with other DNA sequences and affect the transcription and translation of these sequences
Regulatory genes
DNA sequence that are not transcribed but play a role in regulating sequences to whcih they are physically linked are called
Regulatory element
which elements are continuously expressed under normal cellular conditions
Constitutive expression
which elements stimulate gene expression
positive regulation
which element inhibits gene expression
negative regulation
gene expression can be controlled in single or multiple levels
multiple levels
what are responsible for binding to DNA by forming hydrogen bonds with DNA
DNA binding domains
a short sequence/ structure within the DNA binding domain, that fits into the major groove of DNA is called
Motifs
motifs are found on which groove of the DNA
major groove
where are helix-turn-helix located
bacterial regulatory protein; related motifs in eukaryotic protein
where are zinc finger location
eukaryotic regulatory and other proteins
where are steroid receptor located
eukaryotic proteins
where would u find leucine zipper motif
in eukaryotic transcription factors
where would you find helix-loop-helix
eukaryotic proteins
what kind of proteins would u find
homeodomain
what control transcription in bacterial cells
operons
what are the lac mutations
structural gene mutations
regulatory gene mutations
operator mutations
promoter mutations
what does an operon include
promoter+ operator+ structural genes
what type of operons is that in which transcription is usually turn off and needs to be turned on
inducible operons
what type of operons is that in which transcription is normally on and needs to be turned off
repressible operons
small molecule That turns on transcirption is called
inducer
What is the effect of negative inducible operons
it inhibits transcription because molecule binds to operator
what is the small molecule that binds to the repressor and makes it capable of binding to the operator to turn off transcription
copressor
what is the protein that binds to the promoter and thereby increases the efficiency of RNAP binding
Catabolite activator protein (CAP)
what is the regulatory protein involved that stimulates transcription by binding to DNA
activator
Jacob and Monod deduced that operons interfered with the normal regulation in which organism
E.coli
structural genes examples
lacZ, lacY, lacA (ZYA)
which encodes B-galactosidase
lac Z
which encodes lactose permease
lacY
which encodes thiogalactoside transacetylase
lacA
what are regulatory genes and sequences
lacI, lacP, lacO (IPO)
which encodes lac repressor
lacI
does the repression of the lac operon completely shit down transcription
Never Completely
Beta-galactosidase converts lactose to
allolactose
allolactose converts to
galactose and glucose
When lactose is absent from the growth medium, what molecules are produced
B-galactosidase, permease, transacetylase
When lactose is added to the medium and glucose is
absent, what happens
the rate of synthesis of each enzyme increases
about a thousandfold in 2-3 minutes!
increase in protein synthesis is driven by
transcription of the lac operon.
In the absence of lactose, what happens
the regulator protein (a repressor) binds to the operator and inhibits transcription.
which repression favors using glucose when
available and repressing the metabolism of other
sugars.
Catabolite repression
In E. coli, the concentration of cAMP is related to
inversely
proportional to the level of available glucose.
what is an example of a negative repressible operon
the trp Operon
five structural genes in the trp operon
trpE, trpD, trpC, trpB, and trpA
the trp operon gene converts
chorismate to tryptophan
what affects the continuation of transcription, not its initiation.
Attenuation
what is the secondary structure that forms in the
5’ UTR of certain operons that causes the premature
termination of transcription.
Attenuator
what is the protein or DNA sequence that
inhibits the termination of transcription.
Antiterminator
what contain binding sites for
transcriptional regulators but lie at distance
from the gene
Bacterial enhancers
what sequence is complementary to targeted partial sequence of mRNA
Antisense RNA
what molecules influence the
formation of secondary structures in mRNA
Riboswitches
what RNA molecules with catalytic
activity
Ribozymes
when extracellular osmolarity is low,
the ompF mRNA is translated to produce OmpF protein
when extracellular osmolarity is high
blocking the ribosome-binidng site and synthesis of the OmpF protein is reduced.
