Chapter 11: Regulation of Gene Expression Flashcards
True or false: is gene expression precisely regulated?
true
Constitutive genes
actively expressed all the time
Inducible genes
expressed only when their proteins are needed by the cell
Transcription factors
regulatory proteins that controls whether or not a gene is active
repressor
a type of transcription factor
binds near promoter to prevent transcription in negative regulation
Activator
binds to stimulate transctipation in positive regulation
virus
bad news wrapped in protein
aceullar
not cells
do not carry out cell processes
lytic cycle
immediately produces virions, which release as the cell breaks open
Lysogenic cycle
virus incorporates DNA into host DNA in a dormant phase
early stage of lytic cycle
viral genes near promoter are transcribed
mess up regular cell stuff
late stage of lytoc cycle
viral genes transcribed, make proteins, lyse cell
Reverse transcripitase
makes DNA that is complimentary to RNA b
degrade RNA two DNA
provirus
viral DNA integrated in host DNA
inducer
switches genes on
atructural genes
specify the primary structure of a protein molevule that is not involved in regulation
Operon
cluster of genes with a single promoter
operator
part of operon
near promoter controls transcription of structural genes
inducible operon
turned off unless needed
repressible operon
turned on unless needed
What is the key to the lac operon regulatory system?
the repressor protein
co-repressor
part of repressible operon
when it binds to the repressor, the repressor will bind to the DNA/operator amd inhibit transcription
true or false: generally inducible systems control catabolic pathways (turned on when the substrate is available) while repressible systems control anabolic pathways (turned on until the concentration of the product becomes excesssive)
true
Sigma factors
bind to RNA polymerase and direct it to specific promoters
sporulation
a new alternative style that all the hip young bacteria are trying out
reduce metabolism and form a tough spore coat
TATA box
most common core Eukaryotic promoter sequence
General transcription factors
bind to core promoter, allowing RNA poly to bind to promoter
wing women
enhancers
DNA sequences that bind to activators
silencers
DNA sequences that bind to repressors
NFAT
transcription factors that control the expression of the bases of DNA available for H bonding
True or false, if they bind ti the same transcription factors, the expression of genes can be coordinated
true
Can epigenetic changes be passed on to daughter cells?
yes
Epigenetic changes
reversible, non-sequence specific alterations to either the DNA or the chromsomal proteins that package the DNA in the nucleus
DNA methyltransferase
add methyl groups to cytosine covalently
CpG islands
regions r ich in C residues adjaacent to G ones
lots of promoters
Maintenance methylase
catalyzes formation of methyl cytosine bond
demethylase
removes methyl from cytosine
heterochromatn
dark
usyally not transcribed
euchomatin
DNA —> RNA region
a type of chromatin
Barr body
heterochromatic
inactivated gene hanging out in nucleus
Chromatin remodeling
alterationo of chromatin structure
Histone
DNA wraps around it
+ chare
nucleisimw
histone + DNA
histone acetyltransferases
add acetyl griyos to positiveky charged amino acuis
neutralize charge, relweasing it from DNA
promote transcription
histone deacetylase
remove acetyl groups from histones, preventing transcription
True or false: the environment plays a role in epigenetic modifications
true
Alternative splicing
messing up the splicing of introns and exons
can help generate different prtoteins with different jobs
ex. HIV
Drosophila
MicroRNA miRNA
really really small bits of transcribed DNA from noncoding regions
Inhibition of translation with miRNAs
one way to reulate translation
Modification of the 5’ cap
a way to modify translation, needs cap for translation
Translation repressor proteins
a way to modify translation
block translatation by binding to mRNA and preventing attachement to the ribosome
Translational repressor prtein
prevents transaltion
Uniquitin
a certain common chain of amino acids
Proteasome
binds to protein-polyubiquitin molecule
break down proteins