Cell Organelles and Cytoskeleton Flashcards
What process takes place in ribosomes?
protein synthesis = translation!
what are the two types of ribosomes?
membrane bound ribosomes
free ribosomes
what do membrane bound ribosomes do when they are synthesizing proteins that are being translated to the ER lumen?
ER signal sequence
what is ER signal sequence?
N-terminal signal sequence that directs proteins to enter the endoplasmic reticulum (ER). It is cleaved off by signal peptidase after entry.
what do membrane bound ribosomes produce?
lysosomal proteins
secreted proteins
plasma membrane proteins
what does the membrane bound ribosomes use to makes its products?
golgi and ER
what do free ribosomes produce?
nuclear proteins
mitochondrial proteins
cytosol proteins
peroxisome protein
what is the central role of the ER?
lipid and protein biosynthesis
what does the rER do?
protein syntehsis
what does the sER do?
lipid metabolism
detox in hepatocytes by cytochrome P450 system
sequester calcium in muscle cells (sarcoplasmic reticulum)
where is golgi especially well developed?
secratory cells - plasma cells, pancreatic acinar cells
what do coatomer coated vesicles do?
mediate bidirectional traffic between ER and golgi
what does COP 1 coated vesciles do?
Retrograde
CGN to ER
what do COP 2 coated vesicles do?
anterograde
ER to CGN
what are the 3 functions of golgi apparatus?
post translational modification
sorting
packaging
what are the types of post translational modification that can occur?
glycolsylation
sulfation
phosphorylation
proteolysis
what are the 3 vesicle transport pathways in golgi?
consititutive secretory pathway -basolateral -apical regulated secretory pathway lysosomal pathway
what are the 3 major types of granules found in neutrophils?
azurophilic (non specific) (primary)
specific (secondary)
tertiary
where is peroxidase found and what does it do?
found in azurophilic granules of neutrophils (primary)
Generates highly reactive, bactericidal hypochlorite and chloramines
•Kill bacteria and other pathogens following phagocytosis
what are lyososomes?
digestive organelles
what covalently modifies lysosomal hydrates and where is it done?
mannose 6-phosphate
golgi
how do lysosomal storage diseases arise?
genetic defect that affect 1 or more lysosomal hydrolyses - which leads to accumulation of undigested substrates in lysosomes
more than 40 known disorders
what is tay sachs?
lysosomal storage disorder
accumulation fo gangliosides
what are the pathways to lysosomal digestion?
phagocytosis
endocytosis
autophagy - major pathway
what tags proteins to be destroyed by proteasomes?
ubiquitin
what is lipid storage diseases?
lipidoses - accumulation of lipid droplets in abnormal amount or locations
whats found in the innermembrane space of mitochonria?
cytochrome C - important factor in intrinsic apoptosis pathway
what does peroxisome contain and what does that thing do?
catalase - converts hydrogen peroxide to oxygen and water
how are peroxisomal proteins targeted to peroxisomes?
peroxisomal target signal on C-terminus
what is Zellweger syndrome?
defective import of peroxisomal proteins
which part of actin is ATP dependent?
F actin
what is the major player in the actin molecular motor?
myosin II
centrioles provide basal body that is essential for formation fo what?
cilia and flagella
what are the subunits of microtubules?
alpha and beta tubulin protein subunits
microtubule polymerizatin is what?
GTP dependent!
what is Tau associated with (microtubule associated protein MAP)?
alzeihmers disease
what are mitototic spindle poisons?
colchicine and taxol
what two families are involved in microtubule molecular motors?
dynein - fast and large
kinesin
what are cilia and flagella built from?
microtubules and dynein
how is movement produced in microtubule molecular motor ?
bending of the core = axoneme
primary cilia have sensory antennae with mechanoreceptors, if those are fucked up, what is going to happen?
polycystic kidney disease
what is plasma membrane protrusion activated by?
actin polymerization
what are filopodia?
Growth cones
•Core of long, bundled actinfilaments
•Ex. Fibroblasts
what are lamellipodia?
Sheet-like structures
•Ex. Fibroblasts, epithelial cells, some neurons
what are pseudopodia?
3 dimensional projections
•Ex. Neutrophils
how is actin polymerization oriented?
Actinfilaments mostly oriented with plus end facing forward
what is Rho associated with?
stress fibers
what is rac associated with?
lamellipodia
what is cdc 42 associated with?
filopodia and microspikes
Products of inflammation (Ex. Histamine) promote the expression of what on endothelial cell surfaces of neutrophils
selectin receptors
what do chemokines induce the expression of?
Integrinson leukocytes and Integrinreceptorson endothelial cells
what is transmigration?
migration across endothelium
what is the process of diapedesis?
extension of pseudopod between endothelial cells
pass through the basement membrane into the tissue
what is chemotaxis?
movement of leukocytes within the tissue
movement along a chemotactic gradient to the tsource of inflammation
what are 3 possible pathways in the golgi apparatus?
constitutive secretory pathway
regulated secretory pathway
lysosomal pathway
what do neutrophil specific (secondary) granules contain?
lysozymes
lactoferrin
what do neutrophil tertiary granules contain?
phosphatases
metalloproteinases
what are inclusions?
glycogen, lipid and pigemtsn
what part of the mitochondria contains porins?
outer membrane
what is important about the inner membrane of mitochondria?
important factor in intrinsic apoptosis pathway
what makes up the cytoskeleton?
actin, microtubules, intermediate filaments
what are the 6 classes of intermediate filaments?
1 and 2 = keratins 3 = vimentin and vimentin-like 4 neurofilaments 5 = lamins 6= beaded filaments
where does a peroxisome originate from?
preexisting peroxisomes
what undergoes fission?
peroxisomes and mitochondria
how do cells important cholesterol?
recetpro mediated uptake of LDLs in coated vessicles
how does transport of protein from the RER to the VTC occur?
COP II (anterograde - RER to CGM)
how does membrane recycling after exocytosis of the contents of a secretion granule occur?
via clathrin-coated vessicles
when does the uncoupling of ligands and receptors internalized by receptor mediated endocytosis occur?
in the early endosome
proteins targeted for lysosomes (via late endosomes) leave the trans-golgi network how?
in clathrin-coated vesicles
what is a force generating protein associated with microtubules?
kinesin - outward, away from centrosome
globular actin monomers (G actin) polymerize into a double helix of filamentous actin (F actin) aka microfilament in response to what?
regulatory influence of a number of actin-binding proteins
what has 13 protofilament strands
microtubule - alpha and beta tubulin dimers
what are intermediate filaments composed of glial fibrillary acidic proteins and present in fibrous astrocytes?
glial filaments
where is GFAP found?
glial cells - microglia, oligodendrocytes, astrocytes, schwann cells
where is vimentin found?
in cells of CT origin - fibroblasts, chondrocytes, endothelial cells
what do neurons contain?
intermediate neurofilaments - do not stain for either GFAP or vimentin
what is responsible for the cellular protrusion of lamellae podia?
actin polymerization
