Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

BIO 226 > 8 (9) Regulation of Gene Expression in prokaryotes > Flashcards

8 (9) Regulation of Gene Expression in prokaryotes Flashcards

(60 cards)

Start Studying
1
Q

what are the layers of control

A
  • Transcriptional
    ○ How much rna is made
  • mRNA processing
    ○ How quickly RNA is degraded
  • Translation
    ○ How much protein is made
  • Protein function
    ○ stability
    § How quickly protein is degraded
    ○ Regulation
    § Where will proetin localize
    § What others will it interact with
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is controlled transcription

A
  • Both intra and intercellular communication is important in this regulation
    • Affeccted by environmental factores
      ○ Heat, light, signalling molecs
    • +ve and -ve regulatory proteins called transcription factors (TFs)
      ○ Bind to specific regions of DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is a response element

A

binds to a TF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is signal transduction

A

going from the environment to a gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is transcriptional regulation in proks

A

○ RNA polymerase can bind all the promoters
- Function increased by activators and decreased by repressors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is transcriptional regulation in euks

A

○ RNA polymerase cant bind promoter on its own
○ Several levels of protein interaction required
§ Uses TATA box
○ Euks much more complicated than proks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the gene regulatory elements

A

Enhancers
special TFs
General TFs
coactivators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what do enhancers do

A

○ Regions of DNA that bind TFs
○ Tissue and condition specific
○ Can be proximal or dital (close or far)
○ Can be found all over the place

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do special TFs do

A

○ Specific to a subset of genes
○ Binds to enhancers
§ Use that to bind RNA polymerase or other TFs
○ Bind proximal enhancers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what do general TFs do

A

○ Generic
○ Bind all promoter regions
○ Promotes RNA polymerase binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what do coactivators do

A

○ Bind TFs to promote transcription
○ Like inducers but are proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what are the regulatory elements that prevent transcription

A

Silencers(cis)
Repressors(trans)
corepressors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

how do silencers regulate/prevent transcription

A
  • DNA regions for transcription factor binding
  • often tissue/situation specific
  • same function as the operator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do repressors regulate/prevent transcription

A
  • transcription factors
  • bind to silencers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how do corepressors regulate/prevent transcription

A
  • bind TFs to promote transcription
  • like prok corepressors but can be proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the domains found in transcription factors

A
  • always have transcription binding domain
  • protein-protein interactions domains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are the protein interaction domains

A
  • dimerization
  • activation and repression domains
  • ligand binding domains
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the enhanceosome

A
  • recruits chromatin modifiers
  • grp of proteins and TFs that assemble on specific DNA region - enhancer.
  • structure helps activate gene transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what do insulators do

A

tangles the DNA strand so that enhancers are unable to activate genes close to them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the Gal pathway

A

the euk version of the LacOperon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what happens if galactose is present

A

○ Expression of genes req to break galactose –> glucose are increased 1000x
○ Going from sugar to better sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the Gal4

A

○ TF that binds to the enhancers of all the genes
○ When activated transcription for all the genes will proceed
○ Binds DNA (enhancer)
○ Brings activation domain to the promoter
○ Helps recruit RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what regulates Gal4

A

Gal80 and galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

TF Gal4 in the Gal Pathway is = the activator of the LacO path

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
what is chromatin
packages DNA - DNA + Histones
26
____ base pairs are wrapped ___ around a histone octamer
146 7x
27
how many copies of histones are there in each histone core
2
28
TF Regions with lots of chromatin are hard to transcribe
T
29
what are some traits of closed chromatin (heterochromatin)
○ Dense dark regions ○ Often associated with histone methylation ○ High density region ○ Nothing happening to them pretty much
30
what are traits of open chromatin (euchromatin)
○ Low density region ○ Associated with acetylation of histone ○ Things happen here
31
TF Spreading heterochromatin cannnot silence genes
F, it can
32
how does heterochromatin silence genes
- Affects expression of nearby genes - Can cause "position effect variegation" - Can turn gene on or off based on where the heterochromatin is located
33
Nucleosomes are specifically position along genes to influence _________
Transcrition
34
what can be said about the placement of chromatin along the DNA strand
- enhancers are wrapped nucleosome repressed genes - the promoter is often free of nucleosomes
35
what is chromatin remodelling
- Process of moving histones out of the way - Can be post-tranlationally modified by adding a methyl, acetyl, or phosphate grp
36
TF in chromatin remodelling Each tail can be modified at different positions
T
37
what is the histone code
-modifying histone tails
38
what does the histone code use to regularly modify histone tails
Chromatin reader: follows instructions Chromatin writer: adds modification Chromatin eraser: removes modification Chromatin remodeller: moves histones
39
what are the different modifications the histone code makes
○ Methylation § Reduce probability transcription ○ Acetylation § Increase probability transcription ○ Phosphorylation
40
what is the
Order of steps to activate transcription in euks - Cell detects virus - Enhansosome forms from enhancer - Chromatin writers are recruited by enhansosome - Chromatin readers loosen promoter nucleosome - Initiation complex forms - RNA polymerase binds and transcription starts - Eraser proteins remove chromatin mods - TFs and readers release - Chromatin resilences the gene
41
what are 3 facts about heterochromatin
- Grows and shrinks - Prevents transcription - Can be modified via chromatin remodellers
42
TF DNA methylation regulates transcription
T
43
how does DNA methylation regulate transcription
○ Usually added to a C next to a G (CpG) ○ Affects gene and chromatin regulation
44
what is a CpG island
○ 200-4000 CpGs together ○ Mostly on gene promoters ○ Calls for heterochromatin
45
TF DNA methylation can be bad for you
T
46
how can DNA methylation be bad for you
- Can indicate tissue type ○ Turns off brain proteins in ur muscles - Plays a role in disease ○ Can look at the methylation patter in cells and can detect a virus
47
How do modifiers alter gene regulation
- Histone and DNA mods repress and activate transcription - Reader proteins (mCpG + CpG) bind to regulatory sequences DNA and histone modification - Chromatin modifiers (writers+erasers+remoedllers) recruited by reader proteins - Histones and DNA are modified accordingly - TF complexes assemble affecting RNA polymerse recruitment (is activated)
48
what are the functions of Epigenetics
- maintain cell differentiation - maintain hetero/euchromatin - dosage compensation - X-chromosome inactivation
49
what are the 2 layers of control in epigenetics
- Cytoplasmic control of mRNA stability - RNA interference (RNAi)
50
how does cytoplasmic control of mRNA stability work
○ Influenced by several factors ○ Poly A tail ○ 3' UTR sequence ○ Chemical factors ○ Small interfering RNAs (siRNA) or microRNAs (miRNA)
51
what is RNAi (RNA interference)
Short non coding RNAs regulate gene expression ○ Small interfering RNAs (siRNA) - microRNAs (miRNA)
52
how does RNAi work
○ Binds to RNAs to create dbl stranded RNA § Cell thinks its virus § Breaks the RNA
53
what is the specific job of RNAi
reduce expression of target gene by removing mRNAs to prevent transcription
54
what are the dsRNA sources
§ Exogenous dsRNAs § Endogenous dsRNAs § Dicer
55
what are Exogenous dsRNAs
□ Long dsRNAs from foreign sources like transgenes and viral genes
56
what are endogenous genes
□ microRNA genes □ Small non-coding RNA that forms a hairpin
57
what is a dicer
□ Chops dsRNA up into bits □ Bits called siRNA (small interfering RNA) if theyre from longer dsRNAs (exogenous) □ Called MicroRNAs (miRNAs) if they come from endogenous dsRNAs (shorter)
58
what does RICS do
§ Binds to a small bit of dicer product (si or mi RNAs) § Splits the strands § Takes complimentary strand as a guide to get more and chop those up
59
what is an RNAi phenocopy
- Wild type that looks just like the mutant
60

BIO 226 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions