Organelles Flashcards
Where are mitochondrial and ER signal sequence receptors each located?
ER- in cytosol
Mito- in mito membrane
What are two forms of endocytosis? which is constitutive and which is specialized?
pinocytosis (constitutive) (small particles enter cell)
phagocytosis (specialized)
______ endocytosis uses _______ to bring specific macromolecules into the cell
receptor-mediated
pinocytosis
what are the three liquid components of lipid membranes?
phospholipids, glycolipids, cholesterol
What are the phospholipids?
phosphoglycerol, sphingomyelin
what are the sphinglipids?
glycolipids, sphyngomyelin
What role does the mitochondria play in apoptosis?
releases Ca2+ from intermembrane space, into cytosol
then procaspase9 is cleave and activated
then caspase cascade leads to apoptosis
what are the energy requirements for mitochondrial protein translocation?
ATP hydrolysis
electrochem gradient across inner membrane
what is X-linked adrenoleukodystrophy (ALD)?
deficiency of one peroxisomal protein
What does the Unfolded Protein Response do in the ER?
increase chaperones
where does phospholipid synthesis happen?
ER
what do scramblases do and where?
flip phospholipids randomly in ER membrane
then phospholipids go to golgi or PM
what do flippases do and where?
flip phospholipids specifically to achieve asymmetric distribution in golgi and PM membranes
what do adaptin and dynamin do?
adaptin - assembly of clathrin coat
dynamin - pinches off vesicle bud
what molecules are involved in transport vesicle docking?
Rab on vesicle, tethering protein on membrane
what molecules are involved in transport vesicle fusion?
v snare (vesicle) and t snare (membrane) twist
what’s the difference between constitutive and regulated exocytosis?
constitutive is unregulated
regulated requires extracellular signal - hormone or neurotransmitter
How does receptor mediated endocytosis of LDL work?
cell needs cholesterol, puts up LDLR
once receptors go from extracellular (pH 7) to early endosome (pH 6), receptors dissociate
LDL continues to lysosome (pH 6, lots of enzymes) –> hydrolyzed to free cholesterol
How do lysosomal enzymes reach lysosome?
lysosomal enzymes synthesized in ER
ACQUIRES M6P TAG in ER/golgi
then sorted to endosome, then to lysosome
what are four lysosomal storage diseases?
mucopolysaccharidoses
oligosaccharidoses
sphingolipidoses
inclusion cell disease - can’t put M6P on
What is inclusion cell disease?
can’t tag lysosomal enzyme with M6P
what happens by phagocytosis by macrophage?
contents delivered to and destroyed by lysosome
