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Biochem 1 (WPH) > Membranes, Organells, Cytoskeleton - Symes > Flashcards

Membranes, Organells, Cytoskeleton - Symes Flashcards

1
Q

__ are the site of intracellular degredation

A

lysosomes

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2
Q

are lysosomes acidic or basic?

A

acidic

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3
Q

T/F the endomembrane system includes all of the following:

  • plasma membrane
  • ER
  • golgi
  • lysosomes
  • nuclear envelope
A

true

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4
Q

neucleoulus is the site of..

A

rRNA transcription
ribosome assembly
telomerase assembly

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5
Q

T/F the ER and golgi are continuous with the outer nuclear membrane

A

true

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6
Q

in the lysosome:
proteases degrade …
nucleases degrade …
other enzymes degrade…

A

proteins
RNA and DNA
polysaccharides and lipids

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7
Q

microfilaments are made of…

A

actin

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8
Q

mircotubules are made of…

A

tubulin

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9
Q

intermediate filaments are made of…

A

multiple proteins including vimentin, desmin, keratin, and neurofilaments

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10
Q

vimentin, desmin, keratin, and neurofilaments are all subunit proteins of…

A

microfilaments

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11
Q

what are 3 ways lipids can move in a membrane

A

laterally
rotationally
trans (flip-flop)

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12
Q

glycerophospholipids, sphingolipids, and cholesterol compose…

A

the 3 major lipids of biological membranes

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13
Q

what is the structure of a glycerophospholipid

A

polar head connected to one saturated and one unsaturated fatty tail through a phosphate and a glycerol group

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14
Q

describe heredetery sphyrocytosis

A

in the RBC:

  • spectin proteins form a stuctural latticework along membrane surface
  • ankyrin and band 4.1 adaptor proteins connect spectrin lattice to membrane at band 3 integral membrane proteins
  • defects in any of these proteins can cause spherical cells instead of biconcave cells
  • sphericytes cannot squeeze through capillaries and lose membrane and lyse
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15
Q

what are 4 proteins that, if mutated and defective, can cause hereditary spherocytosis

A

spectrin - lattice work along RBC membrane
ankyrin - connects spectrin to band 3
band 4.1 - connects spectrin to band 3
band 3 - integral membrane protein

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16
Q

in a membrane, what is a:
surface protein
peripheral protein
integral protein

A

surface protein - on outer surface
peripheral protein - associated with one side
integral protein - spans whole membrane

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17
Q

what is normal physiolgical temp in C and F

A

37 C

98.6 F

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18
Q

what is pneumonia and what does it look like on chest xray

A
  • lung infection

- hazy area

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19
Q

how are sphingolipids different from gycerophospholipids

A

derived from sphingosine not glycerol

otherwise similar

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20
Q

failure to dispose of what type of membrane lipid most commonly results in lysosomal storage disease?

A

sphingolipids

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21
Q

a cherry-red spot in the retina is caused by what disease?

A

Tay-Sachs disease

lysosomal storage disease

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22
Q 
Tay-Sachs disease
Fabray's disease
Gaucher disease
Niemann-Pick disease
GM1 gangliosidosis
are all what kind of disease?
A

lysosomal storage disease
(all due to mutations in sphingolipase enzymes – and Niemann-Pick may also be caued by mutations in lysosomal cholesterol transporters)

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23
Q

Tay-Sachs disease is caused by

A

a mutation in a lysosomal enzyme that normally breaks down sphingolipids

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24
Q

Fabry’s disease is caused by

A

a mutation in a lysosomal enzyme that normally breaks down sphingolipids

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25
Gaucher disease is caused by
a mutation in a lysosomal enzyme that normally breaks down sphingolipids
26
Niemann-Pick disease is caused by
mutations lysosomal cholesterol transporters and enzymes that normally breaks down sphingolipids
27
GM1 gangiosidosis is caused by
a mutation in a lysosomal enzyme that normally breaks down sphingolipids
28
describe atypical pneumonia
- caused by inhaled bacteria - extracts cholesterol from mucus membranes - causes cilia to go limp (not beat) - muchus accumulation for richer bacterial medium
29
most transmembrane proteins are glycosylated on the __ side of the plasma membrane
non-cytosolic side
30
T/F carbohydrates on the lipid membrane play roles in cell-cell recognition, adhesion, and receptor function
true
31
what are liposomes
bilayered vesicles often used for drug delivery - can make temperature sensitive to target - can attach antibodies to target
32
2 ways to target liposomes for drug delivery
- make temperature sensitive so release contents at site of inflammation or cancer - attach antibodies to target to particular antigen
33
how is membrane fluidity affected by temp increase
more fluid (more kinetic energy)
34
how is membrane fluidity affected by fatty acid chain length
less fluid (more hydrophobic interactions)
35
how is membrane fluidity affected by more unsaturation
more fluid (cannot pack together so well)
36
how is membrane fluidity affected by more cholesterol
less fluid (usually)
37
cystic fibrosis is caused by a defect in what protein?
ABC ATPase pump for Cl-
38
describe hutchison Gilfor progeria syndrom
defect in nuclear laminin causes disruption of shape, function, mitosis, etc cell death
39
T/F the nuclear envelope is made of a lipid bilayer
false - made of 2 lipid bilayers | inner and outer nuclear membranes
40
is the nuclear lamina associated with the inner or outer nuclear membrane?
inner
41
T/F the outer nuclear membrane is continuous with the ER
true
42
what is the nuclear matrix?
a complex of fibrillous proteins thought to be the site of RNA processing
43
what is the nuclear lamina?
a thick layer of fibrous proteins associated with inner nuclear membrane, composed of intermediate filaments
44
what type of cytoskeletal elements form the nuclear lamina?
intermediate filaments
45
this structure stabilizes nuclear structure
nuclear lamina
46
this structure anchors chromatin
nuclear lamina
47
this structure anchors nuclear pore complexes
nuclear lamina
48
this structure regulates assembly and dissassembly of nuclear envelope during mitosis
nuclear lamina
49
T/F a nucleus may contain multiple nucleoli
true
50
what are Nups
nuecleoporins | 8 Nups form an NPC nuclear pore complex
51
how many proteins form an NPC nuclear pore complex
8 Nups nucleoporins
52
3 classes of Nups
- transmembrane Nups - structural Nups - FG Nups (phe and gly residues forming permeability barrier)
53
what is the funciton of FG Nups
phe and gly residues form fishnet permeability barrier to larger molecules
54
T/F hyrdophobicity is a big factor in transport through NPCs nuclear pore complexes
false - size and NLS (nuclear localization signal) are the biggest factors
55
how does an NLS nuclear localization signal work
- NLS binds importins (nuclear import receptors) in cytosol | - NLS importin complex repeatedly binds/unbinds FG Nups to travel across NPC
56
how does an importin (nuclear import receptor) work
- importin binds molecule with NLS - facilitates travel across FG Nups (binding/unbinding repeatedly) - once in nuclease, release cargo, exit to cytosol
57
what 2 tests are performed to deterimine if prostate cancer has metastasized to another suspected location?
PET/CT scan | biopsy
58
in α-β tubulin dimers, which points to the + end and which points to the - end of the microtubule filament?
β + end | α - end
59
what are three tubulin monomers
α, β, γ
60
what is the role of γ tubulin
assembles at - end to template correct assembly of microtubule
61
what are the + and - ends of a cytoskeletal filament?
``` + = fast growing end - = slow growing end ```
62
which are the most often targeted cytoskeletal elements for chemotherapy?
microtubules
63
what are e microtubule motor proteins?
dynein | kinesin
64
how many forms of α and β tubulin are there?
3 α types | 5 β types
65
what protein stabilizes microtubules on the - end?
MTOC
66
what is a MAP protein
microtubule associated protein (e.g. tau) | stabilize microtubules
67
this cytoskeletal element functions in shape, locomotion, contraction, cytokinesis, phagocytosis, and platelet aggregation
actin
68
how many actin subunit types are there
3 | α,β,γ
69
how many actin subunit types form an actin filament?
only one type per filament | α, β, or γ
70
T/F actin is the most commonly targeted cytoskeletal element for drugs
false - microtubules | actin drugs are too toxic for use in humans
71
how do microtubules assemble
α and β tubulin dimerize and polimerize into protofilaments which then associate laterally
72
how many protofilaments in a microtubule?
13
73
``` lamins keratins neurofilaments vimentins glial fibrillary acidic proteins GFAPS desmin are all examples of... ```
intermediate filament proteins
74
how are intermediate filaments assembled?
- α-helical monomers form protofilaments - α-helical protofilaments form coiled coil dimer - dimers associate in antiparallel tetramer - tetramers pack together in parallel - 8 tetramers twist into rope-like filament
75
how many α-helical monomers in a mature intermediate filament?
``` 32? protofilament dimer tetramer 8 tetramers = rope-like filament ```
76
cytoskeletal elements: strung beads tubes rope
strung beads - actin tubes - microtubules rope - intermediate filaments
77
3 steps of cell movement
- leading edge - adhesion/detachment - movement
78
what is a lamellipodium
thin sheet-like projection that pulls cell through tissues
79
filopodia
extension that explores ECM for growth (e.g. neurons and vessels)
80
lamella
behind lamellipodia, couples actin to myosin II contractility
81
what forms lamellipodia
polymerizing actin
82
coflin
severs existing actin filaments
83
this protein severs existing actin filaments
cofilin
84
describe actin polymerization with the following proteins - fibronectin - integrin - Rac1 - WASP/WAVE - Arp2/3 - formin - cofilin
- fibronectin (ECM) binds membrane integrins - integrins bind fibronectin, activate Rac1 - Rac1 - activates WASP/WAVE - WASP/WAVE - activates Arp2/3 - Arp2/3 - promotes actin branching/growth - formin - stabilizes actin - cofilin -severs existing actin filaments
85
how do cells attach to ECM?
fibronectin (ECM protein) binds to integrin | transmembrane receptor protein
86
what protein facilitates trailing edge detachment in cell movement?
Rho A
87
what is the function of Rho A in cell movement?
- inhibit Rac1 (inhibit actin polymerization) - stimulate actomyosin contractility - detach trailing edge
88
what proteins facilitate lamellipodia extension?
- integrins bind fibronectin, activate Rac1 - Rac1 - activates WASP/WAVE - WASP/WAVE - activates Arp2/3 - Arp2/3 - promotes actin branching/growth - formin - stabilizes actin - cofilin -severs existing actin filaments
89
what proteins facilitate leading edge attachment?
fibronectin (ECM protein) binds to integrin | transmembrane receptor protein
90
what proteins facilitate trailing edge detachment?
- Rho A inhibit Rac1 (inhibit actin polymerization) - stimulate actomyosin contractility - detach trailing edge
91
movement of the cell body is achieved through __ __
molecular clutching
92
what is retrograde flow in terms of actin polymerization
actin polymerizes on + end, if not anchored, filament is pushed backward
93
what kind of myosin is relevant in cell movement?
myosin II (non-muscle myosin NMII)
94
how does molecular clutching work in cell movement
disengaged clutch = integrin not bound to actin engaged clutch = integrin bound to fibronectin (ECM) and intracellular actin; actin polymerization causes forward force and movement
95
what proteins are involved in the molecular clutch in cell movement
- integrin, actin, fibronectin - disengaged clutch = integrin not bound to actin - engaged clutch = integrin bound to fibronectin (ECM) and intracellular actin; actin polymerization causes forward force and movement
96
T/F Microtubules are repetitive filaments of covalently bound heterodimers
false - heterodimers are non-covalently bound

Biochem 1 (WPH) (15 decks)

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