Week 6 Flashcards
Cytokinesis
the physical process of cell division, which divides the cytoplasm of a parental cell into two daughter cells.
Transit-amplifying cells (TACs)
an undifferentiated population in transition between SCs and differentiated cells
PET scans
detects metabolically active regions including tumours but also normal kidneys
ionizing radiation
radiation that has enough energy to break an electron away from an atom
Cell fates
- Survive
- Grow and Divide
- Differentiate
- Die
regulated by chemical signalling
necrosis
Cell death by pathogens, poisons, damage,
hypoxia (insufficient oxygen), starvation (lack of
glucose and other nutrients), boiling, dehydration
cytochrome c
one of the mitochondrial proteins that is released into the cytosol when the cell is activated by an apoptotic stimulus.
release of cytochrome c will…
stop ATP synthesis - this stops cell metabolism
- initiates destruction of cell proteins
skin peeling from sunburn
excessive uv exposure damages dna in basal cells and TACs - if dna cannot be repaired, cells stop dividing and die by apoptosis … dead cells detach
whole body imaging - ionizing radiation
x-ray, pet
whole body imaging - non-ionizing radiation
ultrasound, mri
srsi
sense, report, stop and initiate
molecules interacting with molecules
Mitotic spindle defective
chromosomes not attached or not aligned
mitogen
a small bioactive protein or peptide that induces a cell to begin cell division, or enhances the rate of division (mitosis).
word breakdown : mitogen
“Mito” mitosis; “gen” agent or substance similar to
“carcinogen”, a cancer-causing substance.
egf
epidermal growth factor
exposing babies to ionizing radiation…
results in greater risk of gene
mutations and therefore cancer, because they have more stem cells dividing more
often than in adults (due to baby growth and development)
myc gene
stimulates cell division
(named for a cancer in birds in which
this gene and its protein were found to be mutated)
EGF binding to EGR-R changes
EGF-R shape
This shape change enables EGF-R to bind and activate
other proteins (not shown)
when a protein shape changes
its function changes
Ras
named for Rat sarcoma where this protein and
its gene were discovered to be mutated
MAP kinase
a mitogen-activated protein
kinase; “-ase” indicates a protein with enzymatic
activity
protooncogenes and protooncoproteins
cancer promoting
Ras gene(s) are mutated in
30% of all human cancers
(Ras gene mutations promote tumor growth)
- Mutant Ras protein stimulates cell growth
and division even when there is no external
EGF binding to EGF-R
Let-7
a microRNA (miRNA) that regulates many processes in the body
“Post transcriptional”
means that microRNA acts on mRNAs, not on
genes to control protein production
how miRNA (microRNA) work
microRNA (miRNA) bind to
complementary parts of mRNAs.
This region of double stranded RNA
blocks ribosome translation of mRNA
to make protein. No RAS protein is
synthesized
- A region of double stranded RNA cannot be translated by ribosome into protein
The affected mRNA is degraded (broken down)
MRI stands for
magnetic resonance imaging
microRNA
short strands of RNA
- non-coding
- regulates gene expression
ex. Let-7
let-7 found in
present day nematodes
