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39 Cards in this Set
- Front
- Back
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endosomes are found in the ...
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cytoplasm
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What are the 3 major forms of endocytosis?
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phagocytosis
pinocytosis receptor-mediated endocytosis |
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receptor mediated endocytosis includes what 2 forms?
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clathrin-mediated
caveolar-mediated |
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which type of endocytosis takes in
-nonspecific dissolved solutes -water |
pinocytosis
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which type of endocytosis takes in
-large particles -cells -cell debris -particulate matter |
phagocytosis
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which type of endocytosis takes in specific molecules and ligands?
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receptor mediated endocytosis
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phagocytosis is only performed by what 3 specific cell types?
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macrophages
neutrophils dendritic cells |
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the plasma membrane in phagocytosis evaginates and forms ... (false feet)
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pseudopods
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phagocytosis involves a reorganization of ... and ... cytoskeletal components and is a specific and regulated process.
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actin
myosis |
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phagocytosis of a bacterium by a macrophage:
-attachment and activation of ... -... rearrangement and engulfment -formation of ... -... |
surface receptors
actin phagolysosome degredation |
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what does "little sacs of hydrolytic enzymes" describe?
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lysosome
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lysosomes contain # hydrolytic enzymes (lipases, proteases, nucleases, acid hydrolases, carbohydrases)
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40
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the hydrolytic enzymes are only fully active in the acidic pH of the lysosome (~pH ...)
-it is the protective mechanism because you don't want them to become active too early |
4.8
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lysosomal enzymes synthesized in the RER specifically targeted to lysosomes with ... tag
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mannose-6-phosphate
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which type of lysosomal storage disease is this?
-genetic defect in MCP phosphotransferase (enzyme that adds the tag) -lysosomal enzymes never reach lysosome |
I-cell Disease (I=inclusion)
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which category of lysosomal storage disease is this?
-lysosomes are missing a specific enzyme necessary for degredation of a specific ... -accumulation of lipid in lysosomes |
-defects in metabolism of sphingolipids
-sphingolipid |
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which disease is this?
-affects every organ system since lysosomes are defected -clinical manifestations often present at birth -developmental delay, growth failure -inguinal or umbilical hernias -skeletal abnormalities -restricted joint movement -course facial features -recurrent respiratory tract infections -congestive heart failure |
I-cell disease
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what are 4 major target systems of lysosomal storage diseases?
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nervous system
liver spleen bone marrow |
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glucocerebrosidase is the corresponding enzyme deficiency for which lipid storage disease?
-most common |
Gaucher Disease
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what are these?
-Gaucher Disease -Niemann-Pick (A/B) -Fabry Disease -Farber's Disease -Tay-Sachs Disease and Sandhoff Disease -Krabbe's Disease Wolman's Disease |
Lipid storage diseases
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Which type of endocytosis is not a regulated process?
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pinocytosis
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-Pinocytosis is sometimes synonymous with ...
-concerned with nonspecific uptake of ... and ... molecules -occurs in almost all cells and occurs ... -evagination of membrane (creation of pseudopods) |
-endocytosis
-solutes and single -continuously |
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describe Receptor-mediated endocytosis:
-... uptake of specific macromolecules -molecules must first bind to a specific ... to be internalized by the cell -involves ... of plasma membrane (called ...) and pinching off to form vesicles -2 main types: ...-mediated and ...-mediated/...-independent |
-selective
-cell surface receptor -invagination -pits -clathrin-mediated -caveolin-mediated -clathrin-independent |
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Clathrin-mediated endocytosis:
-has receptors located in specialized regions of the plasma membrane called ... --> receptors clustered together -cytoplasmic tail of receptor linked to clathrin by an ... -Ligand binding to receptor causes assembly of clathrin cage and inward budding of a ... |
-clathrin-coated pits
-adaptin protein (AP-2) -clathrin-coated vesicle |
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what are the 3 key players in clathrin-coated vesicle formation?
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clathrin
adaptin (AP2) dynamin |
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what recruits more clathrin and adaptins?
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clathrin
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what pinches off the clathrin-coated vesicle?
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dynamin
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what connects the clathrin to the receptor?
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adaptin
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what are these?
-form when the clathrin cage surrounding endocytic vesicles disassembles, allowing for fusion of several vesicles together. -have an internal pH of about 6, which is maintained by a specific proton pump in the membrane -serve as a "sorting compartment" |
early endosomes
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How do early endosomes serve as a "sorting compartment"
-Due to pH, ligand ... from receptor -receptor or ligand may be ... to cell surface or ... in lysosome |
dissociates
recycled degraded |
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Early endosomes then become ... as the pH continues to drop between 5-6.
-... begins -whorls or small vesicles may form within this, forming a ... body. -eventually fuses with preexisting... |
late endosomes
degredation mutivesicular lysosome |
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LDL enters cells through receptor-mediated endocytosis (...-dependent)
-... on surface of LDL particles serves as ligand -early endosomes ... LDL receptor -late endosome/lysosome is site of accumulation of free ... |
clathrin
apoB-100 recycle cholesterol |
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Familial hypercholesterolemia
-genetic defect in either ... (multiple mutations) or ... (1 mutation) -results in elevated serum cholesterol due to the inability of cells to uptake ... -overall result is ... |
-LDL receptor
-apoB ligand -LDL -premature cardiovascular disease |
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Niemann Pick Disease Type C
-mutation lies in the ... protein, which is involved in transport of cholesterol from late endosomes to the golgi and plasma membrane -cholesterol accumulates in late endosomes forming distinct ... -creates "..." cells |
NPC1
whorls foamy |
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caveolae-mediated endocytosis
-involves ... protein and ... -form ...-shaped pits -responsible for selective uptake of molecules as small as folate to full size proteins such as albumin -also responsible for ...(taken in one side of cell and secreated at other side) |
caveolin-1
lipid rafts flask transcytosis |
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in addition to endocytosis, caveolae and caveolin proteins function in
-uptake of ... and ... -... homeostasis -... ("signalosomes") -Tumorigenesis/... |
viruses and bacteria
cholesterol signal transduction tumor suppressor |
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what is endocytosis of a molecule on one side of the cell followed by exocytosis of the molecule on the opposite side of the cell called?
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transcytosis
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Caveloae may function in ... by acting as a "relay station" to deliver membrane cholesterol to the plasma membrane or to cholesterol-transporters like HDL.
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cholesterol homeostasis
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what are these?
-viruses and toxins have several means to gain entry into cells -examples: adenovirus, Rous Sarcoma virus, cholera toxin, pseudomonas toxin, and diptheria toxin |
opportunistic endocytic ligands
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