Gene regulation Flashcards
how do bacteria regulate their genes?
in respnse to the environment and conditions
what is gene regulation
process of changing and controlling which genes in a cells DNA are expressed to make functional products such as proteins
what does the set of genes being expressed determine?
the cells unique properties
the enes control the set of proteins and this RNAS
why do we alter gene expression?
variation
supression of junk
controls which genes are turned on or not
differeent patterns of speaclist cells
what is a transciptional factor
binds to DNA and switches on or off gnes in repression or in activation
they can bind to other factors leading to pathways
also involved in autoregulation/self regulation
what is a T shape line?
factor that shuts down or repressed the genome
what does an arrow repressent in a flow diagram of transciptional factors
activated or increased genome expression
what inside factors affect gene regulation
proteins, damage to DNA, amount of ATP
whatoutside factors affect gene regulatin
chemical signals from other cells, mechanical signals from ECM, nutrient levels
how is information converetd to a change in gene expression?
molecular pathways
describe the process of a growth signal leading to the cell growing and dividing
- cell detects the factor through physical binding of the factor to receptor protein of cell surface
- binding causes receptor to change shape leading to triggering of chemical events activating transciptional factors
- TF’s bind to sequences of DNA in nucleus and cause transcription of certain genes
for the growth signalling pathway, what is the products/effect at the end
various types of proteins that make the cell dividie and push the cell cycle on
what factors of eukaryotic gene expression can be controlled?
chromatin acessability
transciption
RNA processing
how can chromatin accessability be controlled?
more open or relaxed makes the genes more available for transciption
location of gene promotors relative to nucleosomes and to where the DNA attaches to chromoosomes can affect whether its transcribed
what can you do to chromatin to affect gene expression
chemical modification to histones and chromatin affects structure and gene expression
how can trancription be altered?
sets of transcriptional factors proteins can bind to speicific DNA sequences in or near a gene to promote or repress its transcitpion into RNA
how can RNA processing be alterered to affect gene expression
splicing, addition of poly-A tail to RNA can be regulated so it can exit the nucleus
different mRNAs may be made from the same pre-mRNA by alternative splicing
how does the stability of the RNA molecule impact gene expression?
lifetime of mRNA molecule in cytosol affects how many prpteins can be made from it
what do regulators do?
inrease or inhibitr translation of mRNA
what can a small regulator RNA do?
block transmittion of target mRNA or chop it up
what can be done to proteins to affect activity?
chopped up, tagged with chemical groups
affects the activity and behaviour of the proteins
what is DNA methylation
some genes can be methylated to affect their function
what causes DNA methylation
some enzymes methylate it
what does methylation cause?
if heavy methylated, genes more likely to be turned off and not expressed
removal of methyl groups can turn the genes on
why is methylation important
used in the long-term inactivation of genes that occurs during cells differentiation in embryo differentaition
what can improper DNA methylation cause?
deficient DNA methylation due to lack of proper enzymes can lead to abnormalities in embryos
key features of prokaryote gene regulation
very simple
regulation has little steps
no introns, only one piece
what regulates prokaryote gene regulation?
operons turn genes on
no distinct nucleus to expression in cytoplasm
how do bacteria use gene regulation?
they conserve energy and resources to have a selective advantage over those that cant
natura selection favours bacteria that can express only the genes where the products are needed
how have ecoli adapted gene regulation?
they live in the errati conditions of the stomach and depend on nutrients from the environment
if its lacking amino acid tryptophan, they can respond by activating metabolic pathway to make it from another compound. if the host then eats meal with tryptophan, the bacteria stop making it
why have ecoli adapted for gene regulation in stomach conditions?
stops the bacteria wasting material
they change their metabolism to suit environments
what is a CIS acting sequnce?
one that binds to proteins that in turn assisi the binding of RNA
what is a TRANS acting regulator protein?
they work through sequence-specific DNA binding to their CIS acting regulatory agent sequences
whatis a cis regulatory regions/
bit of DNA where the repressor or factor binds
