Week 2 Science and Scholarships Flashcards
where does DNA replication occur
nucleus
whats the central dogma
DNA to RNA to protein
whats the therapeutic target for DNA replication
cancer cells and various pathogens divide rapidly rely on rapid DNA replication
whats cell division
cell divides and new daughter cells must contain the same genetic information
when does DNA replication occur
S phase
identify parts of cell cycle
G0,1
S
G2
M
how long does DNA replication take
8 hours
what happens in g2
final protein synthesis for cell division
2-5 hours
growth,reproduction,repair
whats on 5th C of nucleotide
phosphate group
whats on 3rd C of nucleotide
OH group
what does semi conservative mean
new double stranded DNA has one strand from parent and one new strand
new DNA formed in DNA replication is called
leading strand
DNA polymerase moves
3’ to 5’
small fragments are called
okizaki fragments
DNA ligase function
ligates the Okazaki fragments to form a unified DNA strand
DNA helicase function
separates the H bonds between complementary bases and unzips DNA
RNA primase function
synthesises a short RNA primer to provide an attachment site for DNA polymerase
exonuclease function
removes the RNA primer
what external insults cause DNA damage
UV
pollutants
mutagenic chemicals
infections
what internal insults cause DNA damage
-DNA polymerase has 1/ 100 mil mutation rate (very low because of DNA repair enzymes)/rapid proliferation
-reactive oxygen species
-metabolic bi products
identify types of DNA damage
breaks
chemical bond between neighbouring molecules
nucleotide modification
chemical linkage of two strand
whats nucleotide excision repair
damaged nucleotide removed and repaired
whats base excision repair
damaged bases are removed and replaced
whats mismatch repair
repairs bases that are wrongly paired
whats non homologous end joining repair
direct ligation
whats homologous recombination repair
undamaged strand from the homologous chromosome is used as a template to correct damage
how’s double stranded DNA repaired
NHEJ
HR
how’s single stranded DNA repaired
nucleotide repair
base repair
mismatch repair
mRNA function
messenger RNA
encodes amino acid sequences from mRNA during translation
tRNA function
transfer RNA
brings s+c amino acid blocks to ribosome during translation
Outline transcription
DNA unwinds, and RNA polymerase attaches to the promoter region for the _____ gene.
DNA template strand is copied into pre-mRNA via complementary base pairing using RNA polymerase. pre mRNA undergoes RNA processing.
Introns are removed, a 5’ methyl cap and 3’ poly-A tail are added to form mRNA.
mRNA for ______leaves the nucleus and goes to a ribosome.
Outline translation
Ribosomes read the mRNA code for _____.
tRNA brings the correct and specific amino acid to the ribosome.
tRNA anticodons are complementary and specific to mRNA codons.
Amino acids are joined together by a peptide bond, in a condensation polymerisation reaction, and a ______ polypeptide is formed
proteins are released for further modification
rRNA function
ribosomal RNA
constitues ribosomes
introns
non coding sections of RNA
exons
coding sections of RNA
Transcription factors
bind to the promoter
RNA polymerase attaches to
promoter TATA region
the template strand is
non coding
non sense
the non template strand
sense strand
coding strand
outline RNA processing
addition of 5’ methyl cap-protection from exonuclease and important for transcription initiation
addition of 3’ poly a tail -promotes RNA stability and export into cytoplasm
introns are removed by splicosomes and exons are alternatively spliced
what occurs in g1
8-12 hours+
preparation for DNA synstheis
generation of organelles
identify stages of mitosis
Prophase
metaphase
anaphase
cytokinesis
first codon of mRNA strand
AUG
identify three stages of translation
initiation
elongation
termination
how many unique amino acids
20
what is the function of proteins
essential to cell function and health
cell shape, organisation, structure and waste management
receives signals and executes cellular responses
what are proteins made up of
polymers of amino acids
what molecules are classified as peptides
<50 amino acids
what molecules are classified as proteins
> 50 amino acids
identity proteins structures
primary
secondary
tertiary
quaternary
outline primary structure
-sequence of amino acids
-begins at the amino terminus and ends at the carboxyl terminus
-hydrophobic and hydrophilic
outline the secondary structure
stabilised by H bonds
in alpha helix hydrogen of carboxyl group bonds with hydrogen of a amino group
in beta pleated sheet parallel peptide chains are linked by H bonds
outline the tertiary structure
3d spatial arrangement of the secondary structure
H bonds
Ionic bonds
Hydrophobic
hydrophilic
disulphide bridges
outline quaternary structure
multiple polypeptide chains held together by non covalent bonds, wan der Waals forces and H bonds
what do structural proteins do
from muscle, bone, skin, connective tissue and cytoskeleton
function of muscle proteins
form thick and thin filaments
contract and relax
identify a few types of muscle proteins
myosin and actin
tropomyosin and troponin
function of collagen
strength shape and support to tissue eg skin
describe the structure of collagen
3 polypeptide chains
triple superhelix stabilised by H bonding
identify three types of cytoskeletal proteins from thinnest to thickest
microfilament
intermediate filament
microtubule
function of microfilament
cell movement
cell shape
transport
cytokinesis
function of intermediate filament
cell shape
anchoring organelles
nuclear lamina
cell to cell junctions
function of microtubules
cell division
formation of mitotic spindle
function of histones
major structural component of chromosomes
forms octamer/nucleosome
idnetify 5 histone proteins
H2A H2B H3 H4 H1
describe structure of transcription factors
binding domain and activation domain
function of transcription factors
promote or interfere with RNA polymerase recruitment
structure and function of cytokines
small proteins/ peptides
produced by immune cells
regulate immunity, inflammation and haemopoiesis
structure of antibodies
two pairs of polypeptide chains form a Y shape
constant and variable region that are held together by disulphide bridges
IgM IgE IgD IgG
structure of complement proteins
there’s over 30 different proteins
function of complement proteins
involved in the innate immune response
-clearing invading pathogens
-form a membrane attack complex
-cell lysis
how many cells in body
40 trillion
how many cell types
200 different cell types
what arises from cell division defects
autoimune
cardiovascular
malignancy
haemetalogical
what is the function/purpose of cell division
tissue development, growth,renewal replacement ,regeneration and repair.
what’s a chromatid
one of two identical halves of a replicated chromosome
outcome of mitosis
cell DNA content is duplicated
cell divides into two identical diploid cells
what does diploid mean
paired chromosomes, one from each parent , 2n
what does haploid mean
single set of chromosomes ,n
most cells are in what stage of cell cycle
interphase
how long does mitosis take
1-3 hours
what happens in cytokinesis
cytoplasmic separation of two daughter cells
what happens in early prophase
DNA coils and chromatin condenses
nuclear membrane disappears
what happens in late prophase
centrosome migrate to opposite poles of cell
what happens in metaphase
chromosomes align in the centre
attached to microtubules held by centrosomes
what happens in anaphase
microtubules pulll chromatid away from centre
what happens in telephone
nuclear membrane reforms
DNA uncoils
G1 to S phase checkpoint
ensures DNA is intact before replication
G2 to M checkpoint
checks that DNA replication is successful
M to A checkpoint
checks that chromosomes are aligned along the equator of the cell
what proteins regulate cell cycle
cyclins (D,E,A,B)
what do cyclin D levels trigger
G0-G1 and G1-S
what do cyclin E proteins do
prepares cell for S phase
what do cyclin A proteins do
activates S phase
what do cyclin B proteins do
mitotic spindle formation
what happens in G0
normal cell function , no preparation
what is p53
anti cancer transcription factor induced by DNA damage, oncogenes and nutrient deprivation
function of P53
maintain genomic stability
initiates apoptosis
inhibits angiogenesis
where does meiosis occur
germ cells that produce gametes
How many cells does meiosis end with
four haploid cells with a single set of chromosomes
how many rounds of cell division in meiosis
two rounds
meiosis I and II
outline DNA change in meiosis
homologous chromosomes–> sister chromatids –> two diploid cells–> 4 haploid cells
End result of meiosis 1
two haploid cells
List the parts of prophase 1
leptonema
zygonema
pachynema
dyplonema
diakiniseis
what happens in leptonema
-diploid chromosomes condense forming long thin threads
-attach to nuclear envelope
-individual chromosomes not visible
what happens in zygonema
-synapsis occurs
-homologous regions of two chromosomes come together
-chromosomes align side by side (zipper)–> tetrad
what happens in pachynema
-chromosomes have aligned
-recombination occur
-exchange of material between two non sister chromatids to create diversity
what is the chiasma
where the two strands of chromosomes overlap and exhgane material
what happens in dyplonema
sister chromatic move away from each other
sister chromatids are visible
what happens in diakinesis
-chromosomes condense
-detach from nuclear membrane
-nuclear envelope disintegrates
sister chromatids joined at centromere
-non sister chromatids joined via chiasmata
what happens in metaphase 1
-spindles form between centrioles at opposite poles of cell
-tetrads line up in the spindles on metaphase plate
-centromeres from homologous chromosomes on opposite sides
-random assortment introduces diversity
what happens in anaphase 1
-spindles pull homologous chromosomes apart
-each cell half has one of a pair of chromosomes (with crossed over material and) one sex chromosome
what happens in telophase 1
-nuclear membrane develops between each set of chromosomes
-cytoplasmic division in males in equal whereas in females its unequal
what happens in prophase 2
nuclear envelope disintegrates
each cell is haploid
what happens in metaphase 2
spindle fibre line up the chromosomes on the equatorial plane
what happens in anaphase 2
centromeres split
sister chromatids pulled to opposite poles
what happens in telophase 2
nuclear membrane forms around each set of chromosomes
outline the structure of antigens
proteins, peptides or polysaccharides
function of antigens
can form complexes with lipids, carbs
bind to antibodies via epitope
identify a few types of antigens
exogenous
endogenous
auto
tumour
native
outline the process of haemostasis
blood vessels constrict
platelet plug
coagulation to form fibrin clot
what is meant by coagulation
process by which blood goes from liquid to gel
identify some coagulation proteins
-clotting factors
-thrombin and fibrinogen
what are clotting factors
-present as inactive proteins (zymogens)
-require activation by proteases
-require Ca2+
identify some anticoagulation proteins
protein c
protein S
thrombomudilin
identify the types of transport proteins
carriers
channels
albumin
describe function of carrier proteins
-use ATP
-moves substance against the concentration gradient
-protein binds to substrate
-the carrier undergoes a reversible conformational change
what molecules are transported by carriers
glucose and large polar molecules
how do channels work
-forms a continuous opening in the membrane
-open to both intracellular and extracellular environments
-can be gated
what molecules move in channels
ions and polar molecules
how many sides of the membrane can carriers open to
one side at a time
what is the purpose of albumin
maintains a constant oncotic pressure of the plasma
carries a negative charge to bind cations and hydrophobic molecules
what bonds are present in albumin
disulphide bridges that form an alpha helix
function of enzymes
catalyse biochemical reactions
contains active site that is s+c to substrate
optimal at certain temperature and pH
identify the classes of enzymes
oxidoreductase
transferases
hydrolases
lyases
isomerases
ligases
function of oxidoreductases
catalyse oxidation reduction reactions
function of transferases
transfer of functional groups
function of hydrolyses
cleavage of bond + addition of water
function of lyases
cleavage of c bond
function of isomerases
rearrangement of bonds
function of ligases
formation of bonds between C,O,N,S
what’s the enzyme marker for MI
troponin
what’s the enzyme marker for brain injury
creatine phosphokinase
what are ligands function
secreted by signalling cells and bind to a target cell
what do all signalling protein receptors have in common
they come in closely matched pairs (a and b)
what do signalling protein receptors bind with
they bind with the ligands via lock and key process
a single ligand can bind with how many cells
as many as it is specific to (more than just one)
hydrophobic ligands bind
intracellular
hydrophilic ligands bind to
surface of plasma membrane
identify signalling proteins
ligands
neurotransmitter
where are neurotransmitters released from
nerve endings
how many neurotransmitters are there
183
identify a few common neurotransmitters
serotonin
adrenaline
GABA
acetylcholine
function of cell adhesion molecules
maintain tissue structure
growth
survival
Identify 4 types of cell adhesion molecules
cadherins
selectins
integrins
intercellular adhesion molecules
what do cadherins do
bind actin intracellularly
vital for cell to cell junctions
what do selectins do
bind carbs on other cells
what do integrins do
bind mainly ECM (colllagen, fibronectin, actin, lamin)
what do intercellular adhesion molecules do
immune response and inflammation
describe the structure of recognition proteins
glycoproteins
cells identity badge
informs immune system as body cell
Outline the functions of plasma cell membrane
-cellular communication
-enzymatic activities
-structural integrity of cell
-maintains composition of extracellular fluid and cytoplasm
-regulates entry and outputs of cell
the ‘heads’ of the plasma cell membrane are
hydrophilic
the ‘tails’ of the plasma cell membrane are
hydrophobic
what makes up the head of a phospholipid
glycerol and phosphate group
identify some accessory features of the plasma membrane
gylcolipids/glycoproteins
cholesterol
integral proteins
peripheral proteins
function of glycolipids and glycoproteins
-important for cell recognition
-bind to extracelular structures
function of cholesterol in plasma cell membrane
rigidity and structure
function of integral proteins in plasma membrane
can acts as transmembrane protein channels
function of peripheral proteins
have regulatory and enzymatic functions
what does selective permeability mean
free passage for some molecules and restricts the molecules
list some hydrophobic molecules
O2
CO2
N2
steroids
lipids
list some small uncharged molecules
glycerol
urea
ethanol
list some large uncharged polar molecules
glucose and sucrose
list some ions
potassium, sodium, hydrogen
what moves by simple diffusion
smaller molecules
non polar
what moves my facilitated diffusion
small and medium sized molecules
does active transport require ATP
yes
examples of passive transport
diffusion
osmosis
facilitated diffusion
how do molecules move in passive transport
down the concentration gradient
how do molecules move in active transport
against the concentration gradient
examples of active transport
phagocytosis
exocytosis
endocytosis
transcytosis
active transport
describe diffusion
movement of substances across a membrane with no energy investment
what’s the difference between membrane channel and carrier molecule for diffusion
membrane channel- water, small molecules
carrier channel-hydrophilic, larger molecules
describe osmosis
diffusion of water molecules across a membrane
what are the two types of active transport
primary and secondary active transport
what is primary active transport
utilises a transmembrane pump and needs ATP
what is secondary active transport
doesn’t directly need ATP and transports two molecules at a time
what is the purpose of vesicular transport
allows for the movement of large macromolecules uitlising small membranous sacs (vesicels)
identify types of cellular signalling
-contact depending signalling
-autocrine signalling
-paracrine signalling
-endocrine signalling
describe direct communication
these are contact dependent interactions
-require cells to have a system to be be able to distinguish between self and non self
describe juxtacrine signalling
-cells directly interact with one another
-receptor expressed on surface of one cell
-ligand expressed on the surface of another cell
-results in downstream signalling events
what are tight junctions
consist of transmembrane proteins
-fuse cells together through plasma membranes
-provide a barrier between cell compartments
what are adherents junctions
-consists of plaques –> thick layer of transmembrane glycoproteins that attach to microfilaments and membrane proteins
what are desmosomes
consists of plaque–> thick layer of transmembrane glycoproteins that attach to intermediate filament and membrane proteins
desmosome vs adherents junction
attach to actin vs keratin
what are hemidesmosomes
-look like half desmosome
-consists of transmembrane glycoproteins that attach to keratin and laminate (basement membrane proteins)
what are gap junctions
-connexon (tunnels) directly link plasma membrane and neighbouring cells
-ions and small molecules pass. through
describe autocrine signalling
-self signalling communication
-signalling cell is target cell
-cell releases ligand that binds to receptor on SAME cell
identify a few examples of autocrine signalling
embryonic development
pain regulation
inflammation
destruction of viruses
tumours
what is paracrine signalling
-short distance -communication
-ligand released by secretory cell
-ligand diffuses across ECM
-affects a nearby cell
-this is a quick and short lasting response
identify two types of neural signalling
electrical and chemical synapses
what are electrical synapses
-direct communication
-gap junctions
-fast synchronised communication
what are chemical synspases
indirect communication
-across synaptic cleft involves neurotransmitters
what is endocrine signalling
-long distance signalling
-slow response
-long lasting
-moves through blood to target cell/gland from endocrine gland
what is neuroendocrine signalling
-released by neuroendocrine or neurosecretory cells
-same process as endocrine signalling
what is formed at end if meiosis
haploid cell with 22 chromosomes plus an (x* or y)
what is cellular differentiation
cell changes from one cell type to another
what are totipotent cells
all cell types including placental tissue and germ cells (gametes)
what are pluripotent cells
all cell types in adults except gametes
what are multipoint cells
multiple different but related cell types within a tissue (limited)
what are unipotent cells
capable of Turing into one cell type
what type of cells are IPSC
induced pluripotent stem cells
what are IPSC used for
disease modelling and tissue regeneration
list stem cells from lowest potency
unipotent
multipotent
pluripotent
totipotent
What are the two types of vesicular transport
endocytosis and exocytosis
what is endocytosis
movement of substances into the cell via invagination of part of plasma membrane that forms vesicles around a substance
what is exocytosis
movement of substances out of the cell
-vesicles migrate to plasma membrane and fuses to it where it excretes contents into extracellular environment
example of endocytosis
neutrophil engulfing bacteria
example of exocytosis
release of digestive enzymes by pancreas
identify the three types of endocytosis
phagocytosis
endocytosis
receptor mediated endocytosis
describe phagocytosis
endocytosis of LARGE particles/”eating”
-utilises phagocytes eg.macrophage
-cytoplasmic extensions (pseudopodia) surround substance to form a phagosome
-phagosome then fuses with lysosome to form phagolysosome
-digestive enzymes digest large particles
-broken down content is recycled or expelled
what is pinocytosis
endocytosis of SMALL particles/”drinking”
-cell engulfs droplets from ECF into tiny vesicles
-process is non specific
-occurs in small intestine and has a role in immune surveillance
what is receptor mediated endocytosis
endocytosis of specific particles
-allows cell to bring in very specific particles that may not be abundant in ECF
-receptor in plasma membrane binds to ligand, invagination occurs and vesicles form
identify the two biological theories of ageing
the programmed theory
the error theory
what is the programmed theory
ageing has an internal clock
what is the error theory
ageing is a result of un repaired naturally occurring internal and external assaults that damage cells and organs (DNA)
what is senescence
-process in which cells cease to divide
-an irreversible block in proliferation
-natural barrier against cancer
-metabolically active
what are telomeres
-DNA sequences
-Caps at the ends of chromosomes
Function of telomerase
enzymes that maintain telomere length
-lengths of telomeres decrease with cell division
3 choices cells have when DNA damage has accumulated
senescence, altered function. or apoptosis
what is progeroid disorder
premature ageing
-mutation effects DNA repair or nuclear structure
what makes up the structure of chromosome
DNA wrapped around histones forms nucleosomes that bind with chromatin to form chromosome
define epigenetic
change in the gene expression that is not dependent on the DNA sequence (rather the histones)
define epigenetic drift
divergence of epigenome due to age
What is global DNA hypomethylation
open chromatin that results in genetic instability
and DNA damage
-senescnece/apoptosis/cell dysfunction
function of stem cells
serve to regenerate, grow and repair body
what is the major driver for ageing
decreased stem cell number and function
how does stem cell exhaustion arise
diminished reservoir of stem cells due to increased differentiation
what is the most conserved pathway in the body
the GH + IGF-1 pathway that allows for nutrient sensing
what does IGF-1 mean
insulin like growth factor 1
GH function
simulates IGF-1 production
IGF-1 function
-informs cells of presence of glucose
-enhances DNA proliferation and damage
what are the hallmarks of ageing
cellular senescence
telomere shortening
DNA damage
epigenetic drift
stem cell exhaustion
deregulated nutrient sensing
inflammaging
mitochondrial dysfunction
what’s inflammaging
increase in innate immunity and a decrease in adaptive immunity
-leads to persistent inflammation
what’s mitochondrial dysfunction and what does it lead to
decrease mitochondria function
-decreased respiration
-increase ROS
-increased apoptosis
-altered metabolites and activation of innate immune system
what are the two forms of cell death
apoptosis and necrosis
What is apoptosis
programmed/regulated cell death
-no inflammation occurs
what is necrosis
unplanned cell death
-leads to inflammation
what pathways are there for apoptosis
intrinsic and extrinsic pathway
outline intrinsic pathway
-internal DNA damage
-pre apoptotic proteins activated and bind to anti apoptotic proteins
-anti apoptotic proteins now inactive
-signal binds to mitochondrial membrane
-disrupts the mitochondrial membrane and cytochrome 3 leaks out
-apoptotic complex forms and
-caspases are activated
-destroys organelles
-phagocytosis occurs
what constitutes an apoptotic complex
capsase and protease
which apoptotic pathway is mitochondrial mediated
intrinsic
which apoptotic pathway is death receptor mediated
extrinsic
outline extrinsic pathway
-external signals received
-involves death receptors found on surface of cell
-bind to ligand that triggers clustering of receptors
-activating apoptotic complex and activating caspases
-destroys organelles
-phagocytosis occurs
key features of apoptosis
cell shrinkage
a cascade of enzyme reactions
nuclear condensation
blebbing that from apoptotic bodies
Outline process of necrosis
-cell swelling
-influx of H2O and ions
-blebbing of cell membrane
-nuclear shrinkage
-nuclear fragmentation
-cell is ruptured and contents spew out into EC environment (inflammation)
identify the steps of how cells communicate 1
signal perception
intracellular signal transduction
cellular response
juxtacrine signalling is same as
contact dependent
what are ligands
extracellular chemical signals eg proteins, ions, lipids
ligands are released by
signalling/secretory cells
what are receptor agonists
lignin binds–> activates–>cellular response
what are receptor antagonists
ligand binds–>no effect itself–>prevents agonist binding
what are hydrophobic ligands
lipid soluble and pass through plasma membrane (bind to DNA in nucleus)
-eg sex steroids, eicosanoids, corticosteroids
how are hydrophobic ligands transported
through circulation, bound to carrier or transport protein
-eventually diffuse through capillaries and bind to cognate receptor
what are water soluble ligands
bind to EC receptors
-eg peptides and small proteins + ECM components
-also water soluble hormones
list some random (non classified) ligands
gases
ions
drugs
neurotransmitters
what are receptors
specific proteins found in or on a cell
classify receptors
Ligand gated ion channels
Enzyme linked receptor
G Protein coupled receptor
Intracellular receptor
How do intracellular receptors work
consist of a binding domain and a DNA binding domain (zinc finger)
-slow effect
how do ligated ion channels work
-receptor on cell surface
ligand binds and
-channel changes shape and opens
-
how do Enzyme/kinase linked receptors work
-receptor on cell surface
ligand binds and
-receptor changes shape
-enzymes activated
-receptor undergoes phosphorilization
-message relayed to other enzymes
how do G Protein coupled receptors work
-receptor on cell surface
-respond to many ligands
-contain G protein that is diffusible through PCM but bound to intracellular surface
-enzymes activated
-cascade of events involving secondary proteins
-signal amplification
how many subunits on G protein
3
G protein is also known as
metabotropic proteins
when G protein is inactive …
-form heterotrimer
-a subunit bound to GDP
-alpha beta and gamma subunits
when G protein is active …
-subunits dissociate
-alpha subunit and beta-gamma subunit
-a subbing bound to GTP
GCPR=
G protein coupled receptor (acts as a switch between 2)
how are signals amplified in G protein receptor
-amplifier enyzmes
-second messenger molecule
-cellular response
what cellular responses do extracellular receptors initiate
cell
-proliferation
-growth
-differentiation
-migration/movement
-survival/death
what cellular responses do intracellular receptors initiate
-target and alter transcription and translation
identify two receptors
GPC
tyrosine kinase
what is meant by atrophy
decrease in cell size and protein content
-shrinkage of tissues
few causes of atrophy
lack of exercise
apoptosis
loss of nerve supply
hormones
what is meant by hypertrophy
increase in cell size and protein content
few causes of hypertrophy
mechanical (stress) and pathological (diseases of heart)
what is meant by hyperplasia
increase in cell number and tissue size
few causes of hyperplasia
increased demand
inflammation
development changes
eg of atrophy
muscle and Brain
eg of hypertrophy
uterus, hypertrophic cardiomyopathy
eg of hyperplasia
gingival hyperplasia
endometrium
what is metaplasia
transformation of one epithelium to another (reversible)
eg of metaplasia
bronchial squamous metaplasia
squamous metaplasia of bladder
what is dysplasia
increase in immature (abnormal and unequal)/ pre cancerous cells
examples of dysplasia
epithelial dysplasia
myelodysplastic syndrome
what is neoplasia
new formation
-uncontrolled proliferation
-loss of OG function
-large nucleus and DNA content increases
-cancerous=benign or malignant
how do cells go form normal to cancerous
normal
hyperplasia
dysplasia
cancerous
identify 5 mechanisms of cell stress
atrophy
hypertrophy
hyperplasia
neoplasia
metaplasia
identify hallmarks of cancer
genomic instability
sustaining proliferative signalling
replicative immortality
resistance to cell death in cancer
tumour-promoting inflammation
dysregulated cell energetics
angiogenesis
avoiding immune destruction
metastasis
how does genomic instability contribute to cancer
-mutations arise
-tumour suppressors become inactivated
-oncogenes become activated
-cell proliferation and avoiding cell death increases
-p53 often mutated
how does sustenance of proliferative signalling contribute to cancer
-excess binding of growth factors to cell receptors
-making cells hyper responsive to growth receptors
-this causes cells to become ‘independent’ to the ligand
-also leads to autocrine signalling
how does replicative immortality contribute to cancer
-due to an enhanced expressions of telomerase
-telomeres do not break down
-hence cells become ‘immortal’/senescence and apoptosis do not occur
how does resistance of cell death contribute to cancer
mutations and genetic abnormalities can lead to
-change in balance of pro and anti apoptotic survival proteins
-cells do NOT undergo apoptosis
what does p53 do
helps maintain genomic stability by either
-ceasing cell cycle, repairing and then resuming cell cycle
-allowing for senescence and apoptosis if cell can’t be repaired
how does tumour promoting inflammation contribute to cancer
inflammation releases factors that promote proliferation and ROS therefore tumorogenesis occurs
what are ROS
reactive oxygen species, O without one electron
how does avoiding immune destruction contribute to cancer
cells can
-produce immunosuppressive chemicals
-reduce immunogenicity
preventing T cytotoxic and Th cells functioning against them
how does angiogenesis contribute to cancer
as tumour growth needs oxygen, nutrients and waste removal
-micro vessels form around tumours that eventually form blood vessels in turn aiding tumour proliferation
how does deregulated cell energetics contribute to cancer
cancer cells need increased ATP at fast rate
-hence glycolysis is favoured which produces organelles and other macromolecules that are essential to cell formation
how does metastasis contribute to cancer
-loss of cell adhesion molecules eg E cadherin
-upregulation of cell migration molecules eg N cadherin
-EMT promotes metastasis
EMT
epithelial mesenchymal transition (don’t attach to basement membrane ) hence cancer cells can migrate
what is meant by efficacy of a drug
maximum effect of a drug we can expect to see
what is meant by potency of a drug
concentration which produces 50% of a maximum effect
what’s a partial agonist (drugs)
drug that is less potent AND less efficacious
what’s competitive antagonism (drugs)
drug that causes less potency but same efficacy (after significant amount delivered)
what’s non competitive antagonism (drugs)
full effect of a drug can not be restored no matter how high the concentration
what’s potentiation (drugs)
drug A may potentiate drug B by increasing receptors affinity for A
-shift left of concentration response curve
what’s drug toxicity
immunological response in which there is too much of the desired effect of a drug
-action at desired receptor or another receptor
identify tissue types
epithelial
connective
muscle
nervous
function of epithelial tissue
protection, absorption, sensation, transport, excretion, vitamin D production
PASTED
Describe structure of epithelial tissue
-highly cellular (epithelial cells)
-avascular
-polar
-apical and basal surface
-basal surface attaches to basement membrane
function of basement membrane
-glues epithelium to connective tissue
-sustains epithelium as they themselves are avascular
-allows exchange of wastes and nutrients but NOT large molecules
Describe structure of basement membrane
20-100 nm thick
-made of proteins and proteoglycans
-fused basil lamina and reticular lamina
-interface between epithelial and connective tissue
cell junctions functions
connect cells and surrounding structures
-anchor all cells together except blood cells
-aid communication
one layer of epithelial cell is classified as
simple
more than one layer of epithelial cells is classified as
stratified t/f protection
flat epithelial cells are called
squamous
cubelike epithelial cells are called
cuboidal
long epithelial cells are called
columnar
where are simple squamous epithelium found
-air sacs of lungs
-heart
-blood vessels
-lymphatic vessels
function of simple squamous epithelium
-allows for diffusion
-releases lubricating fluid
where are simple cuboidal epithelium found
-ducts and secretory portions of small glands
-kidney tubules
function of simple cuboidal epithelium
secretion and absorption & protection
function of simple columnar epithelium
absorption and secretion of enzymes + mucous
where are simple columnar epithelium found
ciliated in bronchus
non ciliated in digestive tract
function of pseudostratified columnar epithelium
secretes and moves mucus
where is pseudostratified columnar epithelium found
ciliated tissues lines upper respiratory tract
where is non keratinised stratified squamous epithelium found
oesophagus, mouth and vagina
function of non keratinised stratified squamous epithelium
protects against abrasion
where is stratified cuboidal epithelium found
sweat, salivary and mammary glands
function of stratified cuboidal epithelium
protection
where is stratified columnar epithelium found
male urethra and some ducts
function of stratified columnar epithelium
secretion and protection
where is transitional epithelium found
bladder, urethra and uterus
function of transitional epithelium
allows urinary organs to stretch and expand
list two epithelial tissue TYPES
glandular and surface
Function of surface epithelium
Covers and lines, all natural surfaces of the body
Function of glandular epithelium
Cells that produce secretion
what is endothelium
Simple squamous epithelium
-thin, smooth and continuous lining
function of endothelium
Extensive diffusion
facilitation of free-flowing fluid
Location of Endothelium
CV systems and lymphatic vessels
What is mesothelium
Simple squamous epithelium
-supported by dense connective tissue
-thin, lubricating cells
Function of mesothelium
Protection and support movement
Location of mesothelium
body cavities
structure of simple cuboidal epithelium
large cells with spherical nuclei
Structure of simple columnar epithelium
-microvilli and tall columnar cells
Structure of non keratinised stratified squamous epithelium
nucleated, squamous cells in superficial layers
upper layers protect underlying tissue
Structure of keratinised, stratified, squamous epithelium
-anucleate cells in superficial layers
-keratinised and hard
function of keratinised, stratified, squamous epithelium
Protective, impermeable layer
What type of epithelia is respiratory epithelium?
Pseudostratified, columnar, cilliated epithelium with goblet cells
function of respiratory epithelium
Filtering air in nasal tract
function of mucocilliary escalator
traps and exports pathogens and dust
structure of transitional epithelium
when stretched appears stratified squamous and when relaxed more stratified cuboidal
what are epithelial glands
glandular cells within epithelial surface
how do glands form
invagination of epithelial cells into underlying connective tissue to support gland
What are exocrine glands
secrete material via duct directly into lumen of organs or onto free surface of epithelium
what are endocrine glands
secret hormones directly into EC space, transported by blood
functions of connective tissue
-provide mechanical support, shape and protection
-connects and binds tissues and organs
-storage, defence and repair
-facilitate communication
structure of connective tissue
made of cells and ECM and fibres
ECM consists of
abundant intercellular proteins
amorphous ground substance
what fibres make up ECM
collagen
elastic
reticular
how are connective tissues classified
-connective
-supporting
-fluid
what constitutes loose connective tissue
predominantly Ground substance
what constitutes dense connective tissue
predominantly fibres
how is dense connective tissue classified
normal and irregular
what is regular dense connective tissue
collagen fibres arranged parallel
what is irregular dense connective tissue
collagen fibres arranged no parallel
function of regular dense connective tissue
-attach bone to bone or muscle to bone
-transmit force
location of regular dense connective tissue
ligaments and tendons
function of irregular dense connective tissue
location of irregular dense connective tissue
fibrous sheath around bones
dermis, liver,spleen
function of loose connective tissue
-nourish and cushion epithelia
-immune defence
-bind organs
-pathway for vessels and nerves
location of loose connective tissue
-fascia between muscles
-under all epithelia
-pleura and pericardial sacs
function of ground substance
-support cells and fibres surrounding
-regulates intercellular communication and transport of substances
amorphous means
no shape
AGS
Amorphous ground substance
structure of ground substance
amorphous
clear, colourless
viscous
scented by CT cells
oedema means
abnormal accumulation of interstitial fluid
what is collagen
-most abundant fibre
-main structural protein
function of collagen
provide strength and cushioning
what is elastin
highly elastic
diminishes as we age
function of elastin
coil and recoil plus flexiblity
what are reticular fibres
delicate, irregular flexible and inelastic
function of reticular fibres
support cellular structures
what is the most common CT cell
fibroblast
function of fibroblast
metabolically active and produces ALL fibres and ground subtstance
-repair
structure of fibroblast
long cytoplasmic processes
structure of adipocytes
made of white and brown fat
function of adipocytes
store fats
insulation
shock absorbers
function of leukocytes
immune response
inflammation
allergy
function of macrophages
act by phagocytosis
function of plasma cells
produce s+c FF antibodies
function of mast cells
release histamine to allow for inflammation response + symptoms
identify the characteristics of muscle tissue
contractile
excitable
what does it mean if muscle tissue is excitable
propagates electrical signals
what does it mean if muscle tissue is contractile
-capable of shortening in length
-capable of returning to natural state
-generates force
what cells make up muscle tissue
mycocytes
characteristics of myocytes
-elongated
-contains microfilaments
-
identify muscle tissue types
Smooth, skeletal and cardiac
structure of skeletal muscle cells
multi nucleated
cylindrical
large
function of skeletal muscles
voluntary control, maintain posture and movement
striated
structure of cardiac muscle cells
Smaller, branching and contain one central nucleus
-connected by intercalated discs
function of cardiac muscle
striated and involuntary
Pumps blood through the chambers of the heart, and circulates blood to the rest of body
structure of smooth muscle cells
Single nucleus, small and spindle-shaped
function of smooth muscle
involuntary and non striated
-constrict blood vessels and airways
-allow food through GI tract
CNS consists of
brain and spinal chord
PNS consists of
nerve endings, nerves and ganglia
Function of nervous tissue
Receiving and generating nervous information
Identify the key properties of neurons
Excitable, conductivity, and secretory
what does it mean if neutrons are excitable
Sensitive to stimuli
what does it mean if neutrons are conductible
Generate and propagate signals
what does it mean if neutrons are secretory
Release chemicals to communicate with other cells
