Organelles

Question 1

Where are mitochondrial and ER signal sequence receptors each located?

Answer 1

ER- in cytosol

Mito- in mito membrane

Question 2

What are two forms of endocytosis? which is constitutive and which is specialized?

Answer 2

pinocytosis (constitutive) (small particles enter cell)

phagocytosis (specialized)

Question 3

______ endocytosis uses _______ to bring specific macromolecules into the cell

Answer 3

receptor-mediated

pinocytosis

Question 4

what are the three liquid components of lipid membranes?

Answer 4

phospholipids, glycolipids, cholesterol

Question 5

What are the phospholipids?

Answer 5

phosphoglycerol, sphingomyelin

Question 6

what are the sphinglipids?

Answer 6

glycolipids, sphyngomyelin

Question 7

What role does the mitochondria play in apoptosis?

Answer 7

releases Ca2+ from intermembrane space, into cytosol
then procaspase9 is cleave and activated
then caspase cascade leads to apoptosis

Question 8

what are the energy requirements for mitochondrial protein translocation?

Answer 8

ATP hydrolysis

electrochem gradient across inner membrane

Question 9

what is X-linked adrenoleukodystrophy (ALD)?

Answer 9

deficiency of one peroxisomal protein

Question 10

What does the Unfolded Protein Response do in the ER?

Answer 10

increase chaperones

Question 11

where does phospholipid synthesis happen?

Answer 11

ER

Question 12

what do scramblases do and where?

Answer 12

flip phospholipids randomly in ER membrane

then phospholipids go to golgi or PM

Question 13

what do flippases do and where?

Answer 13

flip phospholipids specifically to achieve asymmetric distribution in golgi and PM membranes

Question 14

what do adaptin and dynamin do?

Answer 14

adaptin - assembly of clathrin coat

dynamin - pinches off vesicle bud

Question 15

what molecules are involved in transport vesicle docking?

Answer 15

Rab on vesicle, tethering protein on membrane

Question 16

what molecules are involved in transport vesicle fusion?

Answer 16

v snare (vesicle) and t snare (membrane) twist

Question 17

what’s the difference between constitutive and regulated exocytosis?

Answer 17

constitutive is unregulated

regulated requires extracellular signal - hormone or neurotransmitter

Question 18

How does receptor mediated endocytosis of LDL work?

Answer 18

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

Question 19

How do lysosomal enzymes reach lysosome?

Answer 19

lysosomal enzymes synthesized in ER
ACQUIRES M6P TAG in ER/golgi
then sorted to endosome, then to lysosome

Question 20

what are four lysosomal storage diseases?

Answer 20

mucopolysaccharidoses
oligosaccharidoses
sphingolipidoses
inclusion cell disease - can’t put M6P on

Question 21

What is inclusion cell disease?

Answer 21

can’t tag lysosomal enzyme with M6P

Question 22

what happens by phagocytosis by macrophage?

Answer 22

contents delivered to and destroyed by lysosome