Cell Biology Flashcards
List the methods of gene expression control.
chromatin remodelling regulation of transcription alternative mRNA processing microRNA regulation mRNA transport translation control post-translational modification rate of protein degradation
Describe transcription regulation.
transcription factors bind to promoter or enhancer region
activated by environmental stimuli/hormones
Describe alternative mRNA processing.
pre-mRNA converted into multiple types of mature mRNA
Describe microRNA regulation of gene expression.
microRNA (small non-coding) bind to 3’ untranslated region
represses/degrades target mRNAs
Describe post-translational modification.
methylation/phosphorylation etc.
regulate everything
How can genome changes cause disease?
mutations of gene
gene expression changes
modification of mRNA
changes in protein
How does PCR work?
selected DNA sequence is amplified & purified
allows detection of a specific sequence & comparative analysis between sequences
How does in-situ hybridization work?
labelled complementary RNA/DNA localize specific sequence
shows location of sequence within tissue sample
fluorescence can be applied for ease of recognition
Describe DNA microarrays.
different genes attached to probe at fixed locations
can identify multiple genes at the same time
assay gene expression within one sample or compare between
fluorescence can indicate level of regulation
tissue microarray uses clinical tissue not just genetic material
Describe western blots.
identifies specific proteins
electrical current moves proteins through gel
antibody attaches to target protein
secondary antibody attaches to primary antibody
enzyme substrate creates detection signal
Describe immunohistochemistry.
labelled antibodies attached to antigens in tissue sample
locate biomarkers with colour change
uses primary & secondary labelled antibodies
Describe immunofluorescence.
fluorescence labelled antibodies attach to antigens in tissue sample to locate biomarkers w/ fluorescence microscopy
Describe GFP-fusion proteins.
location of proteins within a cell via green fluorescent tags on gene of interest
can see how proteins move around in living cells
What are stem cells?
archetypal cells
self-renewing
differentiate into diverse specialized cells
How do stem cells differentiate?
use symmetric (identical daughter cells) and asymmetric division (identical & progenitor daughter cells)
Describe the difference between progenitor & stem cells.
progenitor - limited self renewal
identical - same potential as parent stem cell
Describe the difference between adult and embryonic stem cells.
adult - multipotent - “repair system” in tissues already partially differentiated (tissue specific)
embryonic - pluripotent, can differentiate into any type of tissue & potentially infinite propagation
How are ESCs acquired?
ICM of blastocyst removed, cultured, proliferated w/o differentiation
Describe the changes in cell colony morphology as pluripotent ESCs differentiate.
start with enlarged nucleus & distinct nucleoli - culture is compact colony of spherical cells
differentiation leads to flattened cells at edges of colony start to migrate out
List potential uses for ESCs.
developmental biology research
drug discovery/development
cell replacement therapy
Describe somatic cell nuclear transfer (SCNT).
donor 1 - remove nucleus
egg cell from donor 2 - remove nucleus
fuse donor 1 nucleus with donor 2 cell, apply electrical current
embryo implanted into surrogate
offspring born with same DNA as donor 1 (clone)
Describe induced pluripotent stem cells (iPS).
somatic cells reprogrammed into ECS via somatic nuclear transfer or ectopic expression of pluripoency-specific transcription factors
How can iPS potentially be used?
differentiate into all 3 germ layers
provide autologous cell source for individualized medicine
Describe haematopoietic stem cells.
both multipotent & able to self-renew
hierarchical differentiation
