Biochemistry Flashcards
What are the 2 ways cells communicate with each other?
electrical communication
chemical communication
which type of cell communication is the major form of information transfer between cells?
chemical
is electrical communication signals fast or slow?
fast
what does electrical communication depend on the presence of?
gap junctions
what is the function of gap junctions?
allow information to pass directly from one cell to its neighbour
in order for a cells signal to trigger a response what must they be transmitted across?
the cell membrane
only cells that have the correct …. on their surface will respond to the signal
fill in the blank
receptor
what does EGF stand for?
epidermal growth factor
what does TGFa and TGFb stand for?
transforming growth factor alpha and beta
what does FGF stand for?
fibroblast growth factor
what enzyme is responsible for phosphorylation?
kinase
what enzyme is involved in desphorylation?
phosphatase
what happens when cell communication goes wrong?
results in disease
what are the types of cell communication going wrong?
losing the signal
when a signal doesn’t reach its target
when its target ignores the signal
too much signal
multiple breakdown
what are the hallmarks of cancer?
sustaining proliferative signalling
evading growth suppressors
activating invasion and metastasis
enabling replicative immortality
inducing angiogenesis
resisting cell death
what are the main growth factors in OSCC
EGF
TGFb
FGF
VEGF
what common receptor activates a range of intracellular signalling pathways which are common in oral cancer?
EGFR
What are the common signalling pathways involved in oral cancer?
PI3 kinase, AKT pathway
JAK-STAT pathway
PKC, IKK-alpha pathway
Ras, Raf and MEK pathway
what antibody therapies are involved in potential target therapy for HNSCC and which one is the most effective?
cetuximab - most effective
trastuzumab
bevacizumab
what does cancer-critical refer to?
all genes whose alteration contributes to, causing or evolution of, cancer by driving tumourigenesis
what does tumourigenesis mean?
tumour development
evolution of the tumour depends upon its microenvironment provided by what cells?
stroma cells
the number and visual appearance of the chromosomes in the cell nuclear of an organism or species is referred to as what?
karyotype
there are 2 main classes of cancer-critical genes, what are they?
proto-oncogenes
tumour supressor genes
mutant, overactive or over expressed forms of proto-oncogens are called what?
oncogenes
define proto-oncogenes
where a gain-of-function mutation can drive a cell towards cancer
define tumour-suppressor genes
where a loss of function mutation(s) can contribute towards cancer
define loss of function
generally refers to the tumour suppressor genes, where loss of function leads towards cancer development
define gain of function
generally refers to a situation where gain of function leads towards cancer development. e.g. when proto-oncogenes are mutated, overactive or over-expressed (now called oncogenes)
what 3 pathways are often found to be damaged in tumours?
p53 pathway
Rb pathway
RTK/Ras/PI3K pathway
define the p53 pathway
genes within the pathway that regulate responses to stress and DNA damage
define the Rb pathway
Rb itself and genes that regulate Rb
Involved in initiation of the cell division cycle
define the RTK/Ras/PI3K pathway
this pathway transmits signals for cell growth and division from the outside of the cell into the cell
what is the protein function of the gene TP53?
Transcription factor
What is the protein function of the gene RB1?
transcriptional co-repression
what is the protein function of the gene PTEN
lipid phosphatase
what is the protein function of BRCA1?
DNA repair, cell cycle control, genomic stability
what is the protein function of ARF?
MDM2 antagonist (p53 stability)
what is the protein function of NF1?
GTPase Activating protein for ras
what gene is p53 encoded by?
TP53
What does p53 activation result in?
cell cycle arrest, senescence and apoptosis
cells lacking in functional p53 will lead to what?
cells may continue to replicate damaged DNA, increasing the chances of accumulating potentially oncogenic mutations
HPV encodes a protein that activates a specific …. enzyme
fill in the blank
E3
what is the name of a protein TAG that attaches to a protein targeting it for degredation
Ubiquitin
mutations in the PI3/AKT/mTOR pathway drive what type of cells to grow?
cancer
cancer occurs/genes there are 4 types of chromosomal mutations, what are they?
deletion: a particular base is deleted
dupplication: a particular base pair is duplicated
inversion: inversion is when a base pair attaches to a different region of the chromosome
translocation: are two chromosome crossing and swaping genes
modifications of DNA that switch specific gene expressions on/off are known as what?
epigenetic mechanisms
the 4 type of chromosonal mutations are an example of epigentic mutations
disruptions in key pathways is common to many cancers
three key pathways more than often found to be affected in tumors
P53 pathway: P53 is produced when damage to the DNA is detected
what are the 3 main functions of P53
produce P21, which is responsible for cell arrest by inhibiting CDK and Cyclin
promotes DNA repair
produces proteins for Apoptosis
which protein is responsible for cell arrest by the inhibition of CDK and Cyclin
P21 is responsible for cell arrest, however P21 is activated by P53
disruptions in key pathways is common to many cancers
three key pathways more than often found to be affected in tumors
the Rb pathway (retinoblastoma) results in the inactivation of the E2F.
what happens when E2F is inactive
E2F is a transcriptase factor and is responsible for reading the DNA, to produce proteins.
E2F is found during the g1 phase of the cell cycle
if there is a mutation of the retinoblastoma protein or the gene that produces the protein. this will result in the failure of Rb protein inactivating the E2F .
as a result the mutated cell will be allowed to move to the next cycle.
disruptions in key pathways is common to many cancers
three key pathways more than often found to be affected in tumors
what is the function of the RAS pathway and how is this affected when somene has cancer.
the function of the RAS pathway is to activate the nucleus to activate the growth genes.
growth factors activate the GFR by binding on to it and this causes phosphorylisation
this pathway transmits signals for cell growth and division from the outside of the cell into the cell.
someone with cancer this pathway is constantly on (oncogene activated)
when damaged DNA is detected, protein kinase activates P53
active P53 then binds where
active P53 binds to the regulatory region of the P21 gene
children who inherit a reccesive tumor supressor gene compared to those who recieve two functional tumor supressor gene.
how does this affect them?
people develop cancers due to complications in the cancer critical genes.
even if there is one functioning tumor suppresor gene the person can be free from cancer.
however due to epigenetic factors tumor supressor genes can be damaged which cause cancer,
soneone with one functioning tumor supressor gene is more likely to develop different cancers at a young age.
The complete DNA sequence of a cancer cell genome can now be easily obtained.
looking for mutations in the genes that code for protein (~21,000 genes), mutations which affect the resultant protein sequence or the expression of the gene
what type of analysis is this
exome analysis
