Cellular I Flashcards
M phase
mitosis and cytokinesis
cyclin-CDK
CDK - inactive
cyclin - activate CDK
regulate G1 > S
p53 and hypo-P Rb inhibit progression
permanent cell
remain G0 - neuron, skeletal m, cardiac m
stable cell
quiescent - enter G1 from G0
labile cell
never enter G0 - rapid division - most affected by chemo
bone marrow, gut epithelium, skin, hair follicles, germ cells
rough ER
synthesis secretory protein
nissl bodies
RER in neurons - NT for secretion
free ribosome
synthesis of organellar and cytosolic proteins
smooth ER
steroid synthesis and detoxification
golgi modification
N-oligosaccharide on aspargine
add O-oligosaccharide on serine and threonine
add mannose-6-P to protein for trafficking to lysosome
mannose-6-phosphate
mark protein traffic to lysosome
I cell disease
inclusion cell disease
-inherited lysosomal storage disease
defect N-acetylglucosaminyl-l-phosphotransferase
failure phosphorylate mannose residues - mannose 6-P
-protein secrete extracellular - instead of delivered to lysosome
coarse facial features, cloudy cornea, restricted joint movement, high plasma lysosomal, fatal in children
inclusion cell disease
-defective phosphorylation manose residues - no trafficking to lysosome
peroxisome
catabolism - very long chain fatty acids, branched chain fatty acids, amino acids
proteasome
degrade damaged or ubiquitin tagged protein
defect ubiquitin proteasome
seen in some cases parkinsons
collagen synthesis pathway
RER synthesis - preprocollagen
> GLY - proline - lysine
> hydroxylation of proline and lysine (Vit C - scurvy)
> glycosylstion of hydroxylysine residues
> form procollagen - via H and disulfide bonds - triple helix (osteogenesis imperfecta - impaired triple helix)
> exocytosis
outside cell - proteolytic processing
> cleavage procollagen - makes insoluble
> reinforce tropocollagen - cross link lysine-hydroxylysine - enzyme lysyl oxidase (copper containing)
glycine content
1/3 collagen
ehler danlos syndrome
problem crosslinking collagen
defective lysyl oxidase
lysyl oxidase
cross link collagen in ECM
-defective in ehler danlos syndrome
vit C deficient
scurvy - cannot hydroxylate proline and lysine of collagne
in the RER of cell
osteogenesis imperfecta
auto dom
-decreased production type I collagen (normal collagen)
blue sclera
multi fractures
hearing loss - abnormal ossicles
dental imperfection
types of ehlers danlos
type 1 - MC - hypermobility
type 2 - classic - joint and skin - collagen type V
type 3 - vascular - type III collagen
menkes disease
X-linked rec - impaired copper absorption
defective menkes protein - ATP7A
decreased activity lysyl oxidase (copper is cofactor)
brittle - kinky hair, growthy retardation, hypotonia
elastin
rich nonhydroxylated proline, glycine, lysine
tropoelastin with fibrillin scaffold
cross linking - occurs extracellularly
elastase - breaks it down - inhibited by a1 antitrypsin
marfan
defect fibrillin
-glycoprotein sheath around elastin
emphysema
a1 antitrypsin deficiecny
-excess elastase activation
wrinkles of aging
decreased collagen and elastin production
actin
microfilament
intermediate filaments
maintain cell stucture
vimentin, desmin, cytokeratin, lamins, GFAP, neurofilaments
microtubules
movement and cell division
mitotic spindle
axon transport
centrioles
desmin
intermediate filament of muscle
vimetin
intermediate filament of CT
cytokeratin
intermediate filament of epithelial cells
GFAP
intermediate filament of neuroglia
neurofilaments
intermediate filament of neurons
microtubule structure
heterodimer alpha and beta tubulin
dimer - 2 GTP bound
dynein
retrograde = + to - on microtubule
kinesin
anterograde = - to + on microtubule
drugs act on microtubule
colchicine paclitaxel vincristine/vinblastine mebendazole griseofulvin
cilia structure
9 + 2 arrangement
axonemal dynein - ATPase that linkes peripheral 9 doublets and causes bending of cilium
kartagener syndrome
primary ciliary dyskinesia
defect dynein arm
infertility - immotile sperm and dysfunctional fallopian tube cilia
increased risk ectopic
situs iversus, bronchiectasis, recurrent sinusitis
fungal membrane
ergosterol
Na/K pump
3 Na out of cell
2K into cell
requires ATP
digoxin MOA
inhibit Na/K ATPase
- leads to indirect inhibition of Na/Ca exchange
- increased Ca
increased cardiac contractility
ouabain
inhibit Na/K ATPase
binds K binding site
most abundant protein human body
collagen
type I collagen
bone, skin, tendon
late wound repair - replace type III
type II collagen
cartilage, vitreous body, nucleus pulposus
type III collagen
reticulin, skin, blood vessel, uterus, fetal tissue, granulation tissue (early wound - replaced by type I)
type IV collagen
basement membrane
alport syndrome
defective collagen type IV
goodpasture syndrome
target collagen type IV BM
vascular ehler danlos
type 3
collagen type III defect - vascular
