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BIO 1200 > Chapter 14: Gene Regulation Prokaryotes > Flashcards

Chapter 14: Gene Regulation Prokaryotes Flashcards

(134 cards)

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1
Q

gene regulation

A

process by which a cell controls whether an active protein is produced from a gene

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2
Q

gene regulation can occur at

A

many different levels of

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3
Q

gene expression

A

gene is transcribed into RNA
RNA translated into protein
protein is converted to the active form of the protein

dna - rna - protein- active protein

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4
Q

constitutive gene expression

A

the gene is expressed at the same level, all of the time, in all cell types

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5
Q

example of constitutive gene expression

A

housekeeping genes enzymes for glycolysis

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6
Q

regulated gene expression

A

many genes are expressed under certain conditions, in certain cell types, at certain developmental stages

at other times the gene is present but not used to make mRNA or protein (gene=off)

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7
Q

example of gene regulation in prokaryotes

A

enzymes for lactose metabolism are only expressed when lactose is present the media

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8
Q

examples of gene regulation in eukaryotes

A

genes that code for protective proteins are turned on when the organism is exposed to uv radiation

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9
Q

multicellular organisms undergo

A

cell differentiation

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10
Q

cell differentiation

A

when a cell becomes a specialized cell thpe

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11
Q

all cells have the same dna but

A

not all genes are expressed in every cell

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12
Q

in skeletal muscle cells, the striped look is from

A

actin and myosin

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13
Q

all cells contain the same ___
each cell type will contain different set of __
•some genes are
each cell type will contains different
• specialized cells ___ and ___

A

dna
rna
•turned on and others are turned off
protein
look different and have different functions

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14
Q

developmental gene expression

A

different genes are expressed in the
embryo, fetus, adult

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15
Q

in prokaryotes, Most gene regulation occurs at the level of

A

transcription

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16
Q

transcriptional regulation

A

controls whether dna is transcribed into rna

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17
Q

most common type of gene regulation in prokaryotes and eukaryotes

A

transcriptional regulation

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18
Q

in transcriptional regulation, rna is only made under certain conditions

A

if the gene is on: high levels of mRNA is made and protein will also be made
if the gene is off: no mRNA is made and no protein will be made

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19
Q

less common type of regulation in prokaryotes and eukaryotes

A

translational regulation

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20
Q

translational regulation

A

controls whether mRNA is used to make protein: mRNA is always made and mRNA is translated into protein only under certain conditions

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21
Q

posttranslational regulation

A

protein has been made
controls whether protein is in the active form (functional) or inactive form (nonfunctional)

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22
Q

common type of regulation of proteins in prokaryotes and eukaryotes

A

allosteric regulation
posttranslational

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23
Q

posttranslational regulation:
gene is always

what is or isn’t made?
form of protein

A

on= constitutive expression
rna is always made
protein is always made
protein can be in two different forms=allosteric regulation

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24
Q

posttranslational regulation: if protein is on
if protein is off

form
function

A

is is in the active form
of can perform its function in the cell

it is in the inactive form
the protein is nonfunctional and can’t do what it is designed to do

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25
In eukaryotes, most gene regulation occurs at the level of
transcription
26
transcriptional regulation in eukaryotes
controls whether dna is transcribed into pre-mRNA
27
eukaryotes also have these types of regulation
transcriptional, translational, and posttranslational
28
regulation of RNA splicing
controls whether pre-mRNA is processed to a functional mRNA
29
what is only in eukaryotes?
regulation of RNA splicing
30
alternative splicing 1 pre-mRNA -> ___ protein
2 mRNA 1-> protein 1 mRNA 2-> protein 2
31
in transcriptional regulation genes can be turned
on and off
32
main way genes are regulated is through
transcriptional
33
in prokaryote transcriptional regulation, when a gene is turned on level of transcription mRNA protein
very high level of transcription large amounts of mRNA are made large amounts of protein are made
34
in prokaryote transcriptional regulation, when a gene is turned off level of transcription mRNA protein
very low level of transcription very low or no mRNA is made very low or no protein is made
35
transcription factor binding
protein that controls whether the gene is transcribed into RNA binds to DNA in the promoter of a gene controls whether RNA polymerase can bind to the promoter
36
types of transcription factors
repressors activators
37
repressors
protein that bind to the promoter of a gene and prevent rna synthesis either completely blocks it or is like a road block and can’t move past it
38
when a repressor binds to the promoter,
it prevents RNA polymerase from binding to the promoter
39
if RNA polymerase can’t bind -> ___ mRNA-> __ proteins
no no
40
what size is RNA polymerase
very large
41
negative control of gene expression
depressor binds to DNA and prevent or decrease amount of transcription from a gene
42
activators
proteins that bind near the promoter of a gene and increase or promote RNA synthesis
43
activators: some genes have ___ promoters so
weak RNA polymerase can’t recognize and bind to these weak promoters efficiently by itself
44
activator binding process
the activator binds to a dna sequence near the promoter helps the RNA polymerase bind to the promoter once the RNA polymerase binds to the promoter it makes mRNA
45
positive control transcription factors
activator proteins increase the amount of transcription from a gene
46
no activator= polymerase ____ bind
can’t
47
the active form of a transcription factor is the form that
can bind to DNA and perform its function
48
the form of a transcription factor is controlled by an
effector molecule
49
effector molecule
small molecule that binds to the transcription factor and changes its shape (allosteric regulation)
50
active form of a repressors
the form of a repressor protein that can bind to dna and prevent transcription
51
active form of an activator
the form of a activator protein that can bind to dna and promote transcription
52
the inactive form of a transcription factor can
not bond to dna so does not carry out its function
53
inactive form of a repressor
can not bind to dna so does not prevent transcription rna is made
54
inactive form of a activator
can not bind to dna so does not promote transcription rna is not made
55
in bacteria genes involved in the same process or pathway are sometimes clustered into an
operon
56
operon
promoter + 2 or more coding regions
57
bacterial genes are in
operons
58
promoter
controls when genes in the operon are transcribed into RNA
59
promoters consist of
LacP and regulatory regions = operon and cap site
60
conserved dna sequences are binding sites for where are the sequences at?
transcription factors promoter
61
binding site for DNA polymerase
lacP
62
sigma factor binds to ___ and ____ sequences
-35 -10
63
RNA polymerase binds to ____ and begins
sigma factor transcription =RNA synthesis
64
weak promoter has
changed sequences
65
transcription factors can’t bind to
changed DNA
66
structural genes
codes for an enzyme or protein a number of genes all controlled by the one promoter each gene codes for a different enzyme or protein involved in the process
67
what are the structural genes names
lacZ lacY lacA
68
an operon is transcribed into a
polycistronic RNA
69
polycistronic RNA
one long mRNA that makes more than one protein has a start and stop for each protein
70
genes are normally off but can be turned on =
induced if a certain effector molecule is present
71
inducible operons example
usually code for genes involved in breakdown pathways (catabolic pathways) lac operons codes for enzymes that break down lactose
72
enzymes for lactose metabolism are produced if Lactose (allolactose) is lac operon will be on if
Lactose is present effector Lactose is present
73
genes are normally on but can be tuned off=
repressed if a certain effector is present
74
repressible operons example
Are usually involved in synthesis pathways (anabolic pathways) trp operon codes for enzymes that make the AA tryptophan
75
enzymes for tryptophan are always made except when effector high amounts of tryptophan =
high levels of tryptophan are present tryptophan trp operon is off
76
the lac operon codes for proteins involved in
lactose metabolism
77
1 long mRNA is
operon
78
lacZ Chemical reaction
Codes for the enzyme b- galactosidase (breaks down lactose) lactose-> galactose+glucose(main reaction) lactose->allolactose
79
lacY
codes for lactose permease (transports lactose into the cell)
80
lacA
codes for enzyme lactose acetylase
81
the lac promoter has __ regions describe
3 promoter=lacP : region where the RNA polymerase binds operator=lacO: where the lac repressor binds cap site: where the cape activator binds
82
LacI
codes for lac repressor has its own promoter not part of the lac operon
83
The lac repressor is ____ produced=
always consitutively expressed
84
no lactose: lac operon=
off
85
lac repressor protein is made in the ____ form
active
86
lacI-> ___-> ____
mRNA lac repressor protein
87
when lac repressor binds to the operator it prevents the
RNA polymerase from binding to the lac promoter
88
if RNA polymerase can’t bind to the lac promoter ___
no RNA or protein will be made form the lac operon
89
lactose present: lac operon=
on
90
repressor + allolactose ->
Inactive
91
if lactose is present in the media, a small amount ___ the cell
enters
92
lactose -> allolactose is by
B- galactosidase
93
allolactose bins to lac ___ and converts it to the ___ form =
repressor inactive turn repressor off
94
inactive form of repressor effector
lac repressor+allolactose allolactose
95
the inactive form of the lac repressor ___ bind to DNA
can’t
96
RNA polymerase binds to the ___ and makes ___
promoter mRNA
97
when RNA polymerase binds, the lac operon is
transcribed into a polycistronic mRNA
98
mRNA is translated into __ proteins needed for
3 lactose metabolism
99
the lac ___ is transcribed into a polycistronic mRNA which includes
operon 1 long mRNA 3 coding regions start and stop codon for each coding region
100
when lac operon is on, lac proteins are made at a ___ level
high
101
permease is needed to
(transport protein) bring lactose into the cell are made
102
many molecule of b-galactosidase enzymes are needed to
break down lactose
103
when lactose is present : the lactose repressor is in the ___ form - bind - formula the lac operon ___ be transcribed into a polycistronic mRNA if the lac operon is expressed, enzymes need to transport lactose into cell and break it down are produced at ___ level
inactive repressor can’t bind to DNA lac repressor + allolactose may high
104
there are __ levels of regulation for the lax operon the levels are
2 repressor and activator (cap)
105
catabolism repression preferred carbon source expressed present and form
glucose is the preferred carbon source (food) genes for glucose metabolism are always expressed= constitutive expression if glucose is present the genes for the metabolism of other alternate sugars (ex lactose) are turned off= repressed
106
genes for the metabolism of other sugars rather than glucose will only be expressed if
glucose if absent and the alternate sugar (lactose) is present
107
the lac operon is highly expressed when
lactose is present: the repressor can’t bind to the dna glucose is absent : activator = cap binds to DNA
108
cap activator greatly increases
amount of mRNA made
109
cap activator proteins will bind to regions in the promoter of genes when
glucose is absent and turn them on
110
the promoters of operons for alternate sugars are
usually weak
111
RNA polymerase can’t recognize and bind to weak promoters without the help of a
activator protein
112
contains many mismatches in conserved sequences in promoter
weak promoter
113
cyclic AMP (cAMP)
controls whether CAP is in the active or inactive form
114
high glucose -> ___ cAMP low glucose-> ____ cAMP
low high
115
hi glucose ___ the enzyme that makes cAMP
116
inactive form of CAP
cap by itself
117
cal is in the inactive form when
high glucose is present in the cell
118
active form of cap
cap + cAMP
119
cap is in the active form when
low glucose is present in the cell
120
CAP + cAMP will bind to promoter and help
RNA polymerase bind
121
what is transcribed into mRNA
lac operon
122
RNA polymerase can only bind if
cap activator binds to promoter region and lac repressor does not bind to operator
123
lactose is present: lac repressor __ bind to operator result
will not lack operon may be transcribed into mRNA nothing prevents the lac operon from being transcribed (it is no longer repressed)
124
glucose is absent: Cap activator ___ bind to CAP binding site result
will CAP and cAMP bins to promoter, helps RNA polymerase bind, mRNA is made
125
RNA polymerase can bind to promoter only if cap level repressor lactose
cap activator binds to cap site low glucose/high cAMP lac repressor does not bind to the operator high lactose
126
the lac operon is ___ the genes are normally turned ___ except when
inducible off lactose is present and glucose is absent
127
low lactose, high glucose-> repressor ___ binds -> __ mRNA
Will no
128
high lactose, High glucose-> repressor ___ bind, RNA polymerase ___ bind-> __ mRNA
Does not does not no or low
129
high lactose, low glucose-> cap ___ binds, RNA polymerase ___ binds, repressor ___ binds-> ___ mRNA
will will Does not high levels of
130
low lactose, low glucose-> cap and repressor ___ bind -> RNA polymerase __ bind -> __ mRNA
will Can’t no
131
what do you need to express lac operon
hi lactose low glucose
132
glucose level controls
cap activity
133
when tryptophan binds to the repressor in the trp operon
it will attach to the operator
134
the repressor is normally ____ on the trp operon lac operon
detached attached

BIO 1200 (17 decks)

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