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Regulation of Gene Expression Flashcards

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1
Q

Group of structural and regulating genes that function as a single unit

A

Operon

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2
Q

Gene that codes for the amino acid sequence of a peptide or protein

A

Structural Gene

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3
Q

4 parts of the operon

A

Regulator Genes

Promoer

Operator

Structural Genes

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4
Q

Normally located outside the operon, this codes for a DNA-BINDING protein that acts as a repressor

A

Regulator gene

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5
Q

Signals the start of the operon and location where transcription begins

A

Promoter

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6
Q

In an operon, Protein molecule that binds to an operator, preventing transcription of structural genes.

A

Repressor

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7
Q

Short portion of DNA located before the structural genes

A

Operator

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8
Q

These genes code for the Enzymes and Proteins involved in the metabolic pathway of the operon

A

Structural Genes

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9
Q

How are trp operons regulated

A

When tryptophan is present in the system it binds to a repressor allowing it to attach to the operon

Stopping the production of more tryptophan

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10
Q

Are operons in Pro or Eukaryotes

A

Prokaryotes

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11
Q

Are operons in Pro or Eukaryotes

A

Prokaryotes

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12
Q

If lactose is present how does this affect the lac operon function?

A

Lactose binds to the repressor stopping it from binding with the operator

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13
Q

Molecule that brings about activity of an operon by joining with a repressor and preventing it from binding to the operator

A

Inducer

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14
Q

Lactose is what to the lac operon?

What does it do?

A

Inducer

Lactose prevents the repressor from binding to the operator allowing for RNA polymerase to bind to the operator allowing for transcription to occur

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15
Q

Which type of pathways are Inducible operons found in?

A

Catabolic Pathways

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16
Q

What is a catabolic pathway?

A

One that breaks down a substance

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17
Q

What is the difference between the role of the promoter and the operator in an operon?

A

Promoter is the location of transcription initiation

The operator is a segment of DNA that regulates whether the structural genes will be transcribed

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18
Q

How does Gene expression differ in an inducible operon vs a repressive operon?

A

Repressive openron is normally on and turned off by the action of a repressor

Inducible operon us normally off and is turned on by an environmental condition

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19
Q

Describe the difference between positive control and negative control of gene expression

A

Positive control is transcribed when it is regulated by a protein that is an activator Not a repressor

Negative control is not transcribed when it is regulated by a protein that is a repressor

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20
Q

Which operon of trp/ lac is catabolic / anabolic

A

trp operon is anabolic ( it builds tryptophan)

lac operon is catabolic (metabolizes lactose)

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21
Q

5 primary levels of control for gene expression of eukaryotes

A

Chromatin structure

Transcriptional control

Posttranscriptional control

Translational control

Posttranslational control

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22
Q

Chromatin packing is used as a way to keep genes….

A

Turned off

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23
Q

Why does chromatid packing affect gene expression

A

RNA polymerase cannot access the genes

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24
Q

Chromatin structure is one example of epigenetic inheritance, what is epigenetic inheritance?

A

Inheritance doesn’t only come from DNA

But also from parents experiences

Parental experiences can be passed to offspring in the form of epigenetic tags

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25
The degree to which a gene is transcribed into mRNA determins the amount of gene product In the nucleus, transcription factors may _____ or _____ transcription, the first step in gene expression.
Transcriptional control Promote / Supress
26
Involves mRNA processing and how fast mRNA leaves the nucleus
Posttranscriptional control
27
Occurs in the cytoplasm and affects when translation begins and how long it continues
Translational Control
28
Takes place in the cytoplasm, Occurs after protein synthesis. Only a functional protein is an active gene product
Posttranslational Control
29
Network of DNA strands and associated proteins observed with a nucleus of a cell
Chromatin
30
Tightly packed chromatin is called? Loosely packed? Which is more associated with active genes?
Heterochromatin = tightly packed Euchromatin = loosely packed Euchromatin is more associated with active genes
31
What works on Euchromatin to make the DNA more available, and the promoter accessible for transcription?
Chromatin Remodeling Complex
32
What is a DNA-Histone complex called?
Nucleosome
33
Which type of histone tail contains Methyl Group (-CH³) Acetylated (-COCH³)
Methyl Group Hetrochromatin Acetylated Euchromatin
34
2 ways on which the chromatin remodeling complex affects gene expression
1. Physically moving nucleosomes to expose promoters | 2. Adding acetyl or methyl groups to histone tails
35
Barr body is which type of chromatin? What is a barr body
Hetrochromatin An inactive X chromosome
36
Protein that participates in the initiation of transcription by binding to the enhancer regulatory regions
Transcription activator
37
DNA sequence that acts as a regulatory element to increase the level of transcription when regulatory proteins, such as transcription activators, bind to it
Enhancer
38
What act as a bridge between transcription factors and transcription activators at the promoter
Mediator protein
39
What does Posttranscriptional control do?
Gene expression following transcription that regulates the way mRNA transcripts are processed
40
Protease do? Where are they found?
Break down proteins Regulate how long protein is active in cell Proteasomes and lysosomes
41
Posttranslational control affects
Activity of a protein product
42
Post script for where an enzyme is stored
Somes Ie. Lysosome
43
A permanent change in the base sequence
Gene mutation
44
Spontaneous mutations aka
Replication errors
45
Induced mutations caused by
Mutagens
46
Point mutations is...
Changing 1 single DNA base
47
Frameshift mutation
1 or 2 nucleotides are inserted or deleted from DNA CATASTROPHIC
48
Lac operator is an example of which kind of control? What happens when lactose is present? When the repressor is removed what happens? What does this enzyme do?
Positive control DNA Polymerase makes a code for Lactase. Breaks down lactase
49
The trp operon is what kind of control? What happens to the repressor when tryptophan is not present? When tryptophan is present what happens with the repressor?
Negative control The repressor is not attached to the operator allowing for DNA polymerase to make Tryptophan The reporesor is on the "on" posistion
50
Where does the Repressor attach?
Operator
51
How do prokaryotes stop making tryptophan? What process happens?
The they have tryptophan it binds to the repressor protein which stops DNA polymerase from coding for more.
52
Carcinogenisis begins with the loss of this type of gene activity and the gain of this type of gene activity
Tumor Suppressor Oncogene
53
When tumor Suppressor genes are inactive and oncogenes are active what occurs?
Uncontrollable Cell Division
54
Tumor Suppressor and proto-oncogenes code for _____ _____
Transcription Factors
55
The operon model states that regulator genes code for ________
Repressors
56
When a repressor binds to the ______, RNA polymerase is is unable to bind to the ______
Operator / Promotor
57
When RNA polymerase is unable to bind to the promoter, transcription of the ______ _______ of the operon cannot take place
Structural Genes
58
trp operon is an example of a _________ operon because when tryptophan is present it binds to the repressor causing it to bind to the operator stopping transcription
Repressible
59
The lac operon is an example of an _______ operon when lactose (the inducer) is present it binds to the repressor cause it Not to bind with the operator allowing for transcription
Inducible
60
Both lac and trp operon exhibit ______ control Why?
Negative The repressor is involved
61
What type of chromatin are exemplified by lampbrush chromesomes in vertebrates?
Euchromatin
62
DNA sequences called ______, play a role in transcriptional control in eukaryotes
Enhancers
63
Regulatory proteins called ______ ______, play a role in transcriptional control in eukaryotes
Transcription Factors
64
Transcription factors bind to ________ Transcription Activators bind to _______
Promoter Enhancer
65
What is involved in RNA interference?
microRNAs, Small Interfering RNAs
66
Type of control that affects whether or not an enzyme is active and how long it is active
Post translational control

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