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MCB > Block 3 > Flashcards

Block 3 Flashcards

1
Q

Amphiphathic

A

Hydrophobic/Nonpolar & Hydrophilic/Polar

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2
Q

Outer Leaflet (Faces extracellular matrix)

A

Glycolipids, Glycoproteins, Proteoglycans

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3
Q

Phosphatidylserine involved in what type of signal?

A

apoptosis

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4
Q

what recognize phosphatidylserine when its flipped to the outer leaflet?

A

macrophages

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5
Q

what forces hold the leaflets together

A

van der waals

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6
Q

Flip-flop requires

A

Flippases and Scrambalases

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7
Q

flippases characteristics?

A

phospholipid specific

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8
Q

scrambalases characteriscs?

A

Non-specific scrambling
• In smooth ER membrane: mix up newly synthesised phospholipids
• Activated during apoptosis

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9
Q

what Increase Fluidity in membranes?

A

Unsaturated Fatty Acids (More
cis-double bond kinks)
• Increase temperature
• Short chains

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10
Q

what Decrease Fluidity in membranes?

A

Saturated Fatty Acids (NO
double bond kinks)
• Decrease temperature
• Long chains

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11
Q

Lipid Rafts

A

Rich in Cholesterol & Glycosphingolipids,

Contain integral & peripheral membrane proteins, GPI: Glycosylphosphatidylinositol anchor

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12
Q

GPI: Glycosylphosphatidylinositol anchor

A

Glycolipid that attaches proteins to PM

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13
Q

Membrane Protein Functions

A

Transport (nutrients, metabolites, ions across bilayer)
• Anchor membrane to macromolecules on either side
• Receptors: signal transduction
• Enzymes (lactase in apical membrane of GI epithelial cells)
• Cell identity markers: MHC
• Protein movement: Rotational and lateral diffusion

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14
Q

Integral transmembrane proteins (30% total proteins, amphipathic)

A

Single: (Glycophorin) /Multipass: (Band3) proteins
• Often α-helical in secondary protein structure
• Receptors (signalling & adhesion), channels, transporters/pumps

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15
Q

Peripheral proteins

A

Located entirely outside but associated with inner / outer leaflet by noncovalent
(often electrostatic) interactions
• Part of cytoskeleton, cytochrome C

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16
Q

Lipid-anchored (peripheral) proteins

A

Located either side of bilayer, have lipid group that inserts into bilayer
• Signaling (Glycosylphosphatidylinositol: GPI – Outer Leaflet) &
Adhesion (Fatty acylation or prenylation link proteins – Inner Leaflet)

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17
Q

Red Blood Cell Membrane main characteristic

A

no nucleus

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18
Q

Two types of Transmembrane proteins present in RBC?

A

glycophorin and Band 3

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19
Q

glycophorin

A

single pass transmembrane protein present in rbc

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20
Q

Band 3

A

Multi pass transmembrane protein in rbc

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21
Q

Peripheral proteins in rbc?

A

Ankyrin and Band protein 4.1

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22
Q

Ankyrin

A

Connects Band 3 with spectrin

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23
Q

Band Protein 4.1:

A

Connects Glycophorin with Actin and also

connects Band 3 with Spectrin “BAG of BS”

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24
Q

Cytoskeletal protein of rbc

A

spectrin

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25
Q

spectrin

A

(α & β chains) that reinforces bilayer, deformable

network, and can withstand stress

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26
Q

Junctional Complex on rbc

A

4-5 tetramers of Spectrin held together by Actin and

Protein 4.1 “SAP”

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27
Q

Acanthocytosis / Spur Cell Anaemia mechanism?

A 
Increase Cholesterol (Transferred to outer leaflet)
defects RBC cell membrane → Acanthocytes →
Decreased deformability → Sequesration and
destruction by spleen → Haemolytic Anemia
→Increase Reticulocytes
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28
Q

Acanthocytosis / Spur Cell Anaemia key words to look for

A

Jaundice, Ascites, Caput Medusa, Chronic Liver

Disease, Acanthocytes, Spur Cells

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29
Q

Acanthocytosis / Spur Cell Anaemia cell biology

A 
Decreased Fluidity:
Increased cholesterol
Saturated fatty acid tails (No cis-double bonds)
Long fatty chains
Decreased Temp
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30
Q

Hereditary Spherocytosis inheritance pattern?

A

Autosomal dominant in 75% of cases

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31
Q

Hereditary Spherocytosis mechanism

A

Defect Spectrin, Ankyrin, Protein 4.1 defects RBC
cytoskeleton membrane → Decreased
deformability → Sequesration and destruction by
spleen → Haemolytic Anemia →Increase
Reticulocytes

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32
Q

Hereditary Spherocytosis key words

A

Splenomegaly, Jaundice, Gallstone

Spectrin, Ankyrn, Protein 4.1

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33
Q

Hereditary Spherocytosis cell biology

A

Spectrin: Cytoskeletal protein that forms junctional
complex
Ankyrn: Peripheral protein that connects Band 3
(multipass transmembrane protein) with spectrin
Protein 4.1: Peripheral protein that connects
Glycophorin with Actin and also connects Band 3
with Spectrin

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34
Q

Glycocalyx

A

5% cell membrane = carbohydrate (prrimary marker for cell recognition)

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35
Q

Glycocalyx function in the cell

A

Protection (from acid, enzymes, etc.)
• Recognition (leukocyte binding to endothelial wall) & Cell adhesion
• Repulsion: negative charges from sialic acid sugars
• Embryonic development: guides embryonic cells to destination

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36
Q

how glycocalyx differ in cancer cells than on normal cells?

A

different sugar coat than noncancerous cells, Immune defense: recognizes difference

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37
Q

Anti-cancer therapy and glycocalyx

A

target enzymes that assemble tumor Glycocalyx

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38
Q

Electin

A

important for binding to sugar chains involved for cell to cell
recognition

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39
Q

L-selectins recognise?

A

addressins on lymphoid organ endothelial cells

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40
Q

G protein Cycle

A

The GTP “switch”

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41
Q

Small monomeric G proteins

A

RAS, RHO, RAB, RAN, ARF

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42
Q

Every G protein has what in coomon?

A

GAP and GEF

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43
Q

GAPs

A

GAPs: “Turns OFF” Hydrolyze GTP to GDP “GAP turns me OFF”

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44
Q

GEFs: guanidine nucleotide exchange factor

A

“Turns ON” Exchange GDP for GTP “GEF turns me ON”

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45
Q

Nuclear Import

A

process that imports cargo from the cytosol into the nucleus

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46
Q

cargo protein that is destine to go into the nucleus contains?

A

Nuclear Localization Signal (NLS)

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47
Q

Importin

A

(Import receptors in cytosol) binds NLS & nucleoporins:

Imports

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48
Q

nuclear export

A

process to carry cargo from the nucleus to the cytosol. such as ribosomes or mrna

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49
Q

cargo protein that is destined to go out of the nucleus contains what?

A

Nuclear Export Signal (NES)

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50
Q

Exportin

A

(export receptors in nucleus) binds NES & nucleoporins:

Exports

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51
Q

Import & Export require what?

A

Translocation of protein complexes through NPC requires energy
(RAN GTPase)

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52
Q

Nuclear Import steps

A 
1. Importin binds to Cargo w/
NLS in cytoplasm
2. Cargo-Importin binds to NPC to
enter the nucleus
3. Ran-GTP binds to Importin thus
creating dissociation of Cargo
in nucleus
4. Importin-GTP enters cytoplasm
5. Ran-GAP hydrolyzes Ran-GTP
→ Ran-GDP thus creating
dissociation of Importin in
cytoplasm
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53
Q

nuclear export steps

A 
1. Exportin bound Ran-GTP binds
to Cargo w/ NES in nucleus
2. RanGTP-Exportin-Cargo complex
binds to NPC enter cytoplasm
3. Ran-GAP hydrolyzes Ran-GTP →
Ran-GDP thus creating
dissociation of Exportin, Cargo,
and Ran-GDP
4. Exportin returns back to nucleus
(Does NOT need signal to return
back to nucleus)
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54
Q

Ran GEF

A 
• Guanidine Nucleotide
Exchange Factor
• ON SWITCH
• Exchange GDP with GTP
• In nucleus
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55
Q

Ran GAP

A
  • GTPase Activating Protein
  • OFF SWITCH
  • Hydrolyze GTP to GDP
  • In cytosol
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56
Q

related to the nuclear envelope, what triggers the start of mitosis

A

Lamin phosphorylation

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57
Q

when is lamin phosphorylated and which kinase does the job?

A

during prophase 1 by Cdk1

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58
Q

what is the result of the phosphorylation of lamins?

A

nuclear lamina disassembly

→ nuclear envelope disassembly into vesicles containing Lamin B

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59
Q

how are lamins A, B and C released after phosphorylation?

A

Lamins A & C released as free dimers

• Lamin B = anchored to inner membrane

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60
Q

what triggers the end of mitosis? by what process?

A

Lamin Dephosphorylation → Inactivation of Cdk1

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61
Q

process of nuclear reassembly after mitosis?

A
  • Membrane vesicles bind chromosome surface → reassembly

* Telophase: Lamin A and C start to bind again to lamin B

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62
Q

nuclear membrane outer layer is continous with what other organelle?

A

Rough ER

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63
Q

On the outer membrane of the nucleus are proteins that interact with what?

A

cytoskeletal fillamets

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64
Q

function of nuclear lamins?

A

Maintain structure & stability:
attaches to integral membrane
proteins & NPCs (important for
spatial separation), protects DNA

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65
Q

Nucleolus substructures

A

Fibrillar center, Dense fibrillar components / pars fibrosa “Fibrillar Fix”, Granular component / pars granulosa “Great Assembly”

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66
Q

Fibrillar center of nucleolus

A
  • Transcriptionally inactive DNA

* NORs (Nucleolar Organiser Regions: pre-rRNA genes located)

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67
Q

Dense fibrillar components / pars fibrosa

A

“fibrilar fix” •rRNA being transcribed then cleaved & modified by snoRNPs

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68
Q

Granular component / pars granulosa

A

“Great Assembly”

•rRNAs begin assembly with ribosomal proteins

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69
Q

Hutchinson-Gilford Progeria Syndrome inherritance pattern?

A

(Autosomal Dominant Sporadic)

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70
Q

Hutchinson-Gilford Progeria Syndrome mechanism?

A

“progeriA defect lamin A”
Defect in ONLY Lamin A → Unstable Nuclear Envelope (Bleb
formation, Loss of peripheral heterochromatin, NPC clustering)
→ Progressive Nuclear Damage → Premature Cell Death

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71
Q

Hutchinson-Gilford Progeria Syndrome key words

A

“Premature Aging”
Lamin A, Prominent eyes, Alopecia (Loss of hair), Loss of
subfat, Arteriosclerosis, Joint stiffness, Accelerated age, Bleb
formation

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72
Q

Hutchinson-Gilford Progeria Syndrome cell biology

A

Arteriosclerosis: Scarring of vesicles and become hard

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73
Q

co-translation translocation meaning

A

transport into the ER

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74
Q

Post-translational translocation?

A

transport into other organelles

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75
Q

Emery-Dreifuss muscular dystrophy

affect which part of the cell?

A

Nucleus

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76
Q

Emery-Dreifuss muscular dystrophy

what type of effect on the organelle it affects?

A 
Mutation Emerin or LaminA/C
Contractures, especially in the elbows, ankles, neck → Flexion deformity of elbows, limited neck flexion
Muscle weakness & atrophy
Conduction defects & arrhythmias
Sudden heart failure common
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77
Q

Cotranslational Translocation steps

A
  1. Signal Recognition Particle (SRP) binds to ER signal sequence
    on protein
  2. SRP binds to SRP receptor in ER membrane
  3. SRP brings ribosome to translocon (pore complex) and transfers the
    ribosome
  4. SRP displace and recycled
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78
Q

BiP (Binding Protein):

A

Lumenal ER chaperone (help proteins fold)

and binds peptide in ER lumen & pulls it in

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79
Q

Signal peptidase cleaves what off

A

N-terminal signal peptide as protein

enters ER lumen

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80
Q

what doenst get cleaved during cotranslational translocation?

A

the internal sequences of proteins

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81
Q

Single-Pass Transmembrane Proteins, N-terminal signal sequence job

A

(Start Transfer signal) initiates

translocation (Gets Cleaved)

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82
Q

Single-Pass Transmembrane Proteins, Stop Transfer signal job

A

Anchors protein in membrane AFTER ER signal sequence is cleaved

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83
Q

Single-Pass Transmembrane Proteins, Internal signal sequence job

A

(start transfer signal) initiates

translocation (NOT cleaved)

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84
Q

Multipass transmembrane proteins

A

• Internal signal sequence (start transfer signal)
• Stop transfer sequence
• The multiple stop signals
→ Many hydrophobic α-helices cross the membrane

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85
Q

If a protein has an N terminal ER signal sequence, and two additional
hydrophobic stretches of amino acids, what type of protein is this?

A

Transmembrane

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86
Q

If a protein has an N terminal ER signal sequence, and two additional
hydrophobic stretches of amino acids, where will the C terminus of the protein be located?

A

ER lumen

87
Q

r ER fuction

A

Produces proteins destined for the ER, Golgi apparatus, endosomes, lysosomes, plasma membrane, & for secretion

88
Q

what do Free ribosomes synthesise

A

all other proteins & discharge in cytosol

(proteins targeted to nucleus, mitochondria, peroxisomes; post-translational translocation)

89
Q

Dolichol

A

is a membrane bound lipid that attaches 14 sugars to asparagine nonspecifically on proteins in the rER
• “N-linked: Asparagine.
2) the 14 sugar oligosaccharide gets assembled temporarily on it. It serves as an achor so when the protein gest made the sugar string is made and transferred to the nitrogen of the asparagine AA.

90
Q

Oligosaccharide Processing in the ER

A

4 sugars removed from the N-linked precursor oligosaccharide (still in the
ER) signals time to move to Golgi

91
Q

Glycosylation: Important for?

A

correct folding, transport, and function

92
Q

O-Linked: Hydroxyl?

A

Processing of proteins that continues in Golgi (Specificity) after N-glycosylation in the ER

93
Q

where does O-Linked: glycosylation of collagen takes place?

A

in the ER

94
Q

where does protein without ER signal sequence end up?

A

in the cytosol

95
Q

where does protein with NLS signal sequence end up? and what AA sequence they are?

A

in the nucleus

Asp, Leu, Ser

96
Q

where does protein with SKL signal sequence end up? and what AA sequence they are

A

peroxisomes,

Ser, Lys, Leu

97
Q

where does protein with mitochondrial signal sequence end up? and what AA sequence they are

A

mitochondria

98
Q

where does protein with KDEL signal sequence end up?

A

ER, soluble

“KDEL is solubel”

99
Q

where does protein with KKXX signal sequence end up?

A

ER (transmembrane) where XX is any amino acid

100
Q

where does protein with M6P signal sequence end up?

A

Lysosome

101
Q

where are the default destinations for proteins with no signal sequence?

A

plasma membrane and for secretion

102
Q

If a protein has an ER signal sequence and one internal stop transfer
sequence (no other sequences or tags) where will it end up? why?

A

In the plasma membrane (cell surface) WHY b/c it has no KDEL or KKXX

103
Q

exocutosis

A

deliver proteins to plasma membranes and extracellular space

104
Q

two tyupes os secretion

A

constitutive and regulated secretion

105
Q

constituitive secretion

A

proteins are secreted as soon as they are made. examples are trans-membrane proteins

106
Q

regulated secretion

A

vesicles are ready and docked to the plasma membrane and waiting for a signal molecules to tell them to be secreted.

107
Q

how regulated secretion work

A

vesicles are charged with proteins to be delivered, signal comes com outside the cell, opens calcium ion channels that allows calcium to rush into the cell and interact twith the vesicle allowing it to fuse to the membrane

108
Q

how vesicles endup in the lysosomes?

A

M6P signal

109
Q

transcytosis

A

combination of endo and exocytosis. example: maternal IgG antibodies in breast milk are transported across intestinal epithelial cells

110
Q

processing in secretory vesicles

A

concentration of proteins and transport recycled from endosomes back to golgi

111
Q

progressive acidification allows for

A

activation of enzymes that will modify proteins contained into the vessicles

112
Q

pre-pro-proteins

A

example: proalbumin to albumim

113
Q

whats included in the recycled vesicles going back to the golgi

A

cargo receptors which will go back and pick up more cargo

114
Q

RAB-GTP

A

regulates initial docking and binding of SNAREs. GTP hydrolyses to GDP

115
Q

SNARE

A

proteins that provide specificity v-SNARE and t-SNARE

116
Q

v-SNARE

A

interact with v-snare to form complex

117
Q

synaptoragmins

A

calcium ion channels that open to allow calcium to go in the cell that allow v and t snares to fuse and let the vesicle bind the membrane and move on to the exocytosis process

118
Q

botulin toxin mechanism to paralysis

A

the neuro muscular junction contain Ach, the toxin cleaves the v-snares on vesicles that contain Ach. resultis in not being able to fuse their vesicles with the membrane and not release ACh into the muscle

119
Q

botulism

A

flaccid paralysis. floppy baby syndrome.

120
Q

tetanospasmin mechanism

A

cleaves v-snare of vesicles containing GABA and glycine, will result in spastic paralysis.

121
Q

initial signs of tetanus

A

trismus (lockjaw). nech stiffness, dysphagia

122
Q

simple test for tetanus

A

spatula test. induce gag reflex will result in patient locking jaw

123
Q

Endocytosis

A

how things get into the cell

124
Q

how many types of endocytosis

A

3: pinocytosis, phogocytosis, receptor mediated endocytosis

125
Q

pinocytosis

A

cell-dringling (fluid and solutes)

126
Q

phagocytosis

A

cell eating (food, development, defense) completely non-specific

127
Q

receptor mediated endocytosis

A

clathrin-coated pits, caveolin-coated cavellae

128
Q

two functions of endocytosis

A

bring material into the cell and reclycle plasma membrane

129
Q

what types of cell undergo pinocytosis?

A

all cells

130
Q

what causes membrane deformation for vesicles budding?

A

actin filaments

131
Q

opsonins?

A

anything that a macrophage has a receptor to bind to

132
Q

what happens when macrophage binds to a cells opsonis?

A

the actin filaments are activated and start to change the shape of the membrane to start engolphin the dying cell

133
Q

phases of phagocytosis

A

attachment, engulfment, fusion, difestion

134
Q

attachmetnt phase of phagocytosis

A

phagocyte binds to opsonins

135
Q

engulfment phase during phagocytosis

A

binding of receptors to foreign particles initiates actin filaments assembly. phagocytic cup form around foreingner

136
Q

residual body

A

anything that cant be digested in the phagolysosomes, that will be secreted from the cells

137
Q

receptor mediated endocytosis

A

protein coat binging to the membrane to initiate, (a hormone for example)

138
Q

lipid rafts

A

concentrate proteins inthe same place in the mmembrane

139
Q

dynamin

A

large Gprotein use ennergy to squeeze vesicle trhough membrane

140
Q

what allows the cargo to be released into the endosome from vesicles

A

higher pH

141
Q

steps in endocytic vesicle formation and destination

A 
1 AP (adaptins recruitments
2 clathrin assembly ???
142
Q

endosomes

A

immature lysosome

143
Q

what endosomes contain

A

endocytic material, concentrate the materials

144
Q

example of membrane reclyng

A

LDL recptor to pick up more cargo

145
Q

familial hypercholesterolemia

A

mutation on LDL-R that increases cholesterol, increases synthesis LDL, the receptors dont fold into lipid rafts. makes it difficult to proteins to cluster there, endocytosis will not work there

146
Q

types of mutation on LDL-R

A

affects: synthesis, transport, biding, clustering, recycling

147
Q

what any of the mutation in LDL-Receptor result in?

A

hypercholesterolemia

148
Q

caveolin-coated vesicles

A

type of coat protein in the membrane, they cluster into lipid rafts to dissociate the vesicle. (just recognize that it is a type of coat protein

149
Q

Lysosome?

A

principal sites of intracellular digestion

150
Q

what is the pH of a lysosome?

A

around 4.5

151
Q

types of lysosome?

A

primary: only contain lysosomal enzymes directly made from transgolgi
secondary: fusion of primary lysosome with substrate to be degraded, involved in varioys stages of degradation

152
Q

what is contained within late endosomes?

A

material from endocytosis and hydrolytic enzymes

153
Q

vesicles from early endosomes bud off from early endosomes and go to the golgi carrying what?

A

receptors to be recycled

154
Q

waht any vesicles traveling in the cell have in their membrane?

A

hydrogen pumps, to make the inside more acidic

155
Q

difference of endosome and lysosome,

A

echo

156
Q

difference btw early and late lysosome

A

echo

157
Q

when a endosome become a lysosome?

A

when all enzymes are fully active

158
Q

M6P tag

A

echo

159
Q

how are cathrin-coated vesicle created?

A

1 cargo receptors bind cargo proteins,
2 receptors concentrated in membrane
3 adaptins link receptors to clathrin coat proteins
5 coat proteins disassemble, exposing Rab and SNAREs then docking and fusion

160
Q

transport of hydrolases to lysosomes steps

A

Cargo binds to M6P Receptor
M6P Receptor clusters, with adaptors, clathrin buds off vesicle
Clathrin coat removed & fusion with acidic endosome
Acid dissociates cargo from M6P receptor
Phosphate removed from cargo so can not rebind to M6P receptor
M6P Receptors recycled to TGN

161
Q

Acidification of Endosome & Lysosome

A

V-type ATPase (H pumps), use energy from ATP to pump H+ into the lumen to make it more acidic

162
Q

3 pathways to degradation in lysosomes

A

Endocytosis
Phagocytosis
Autophagy
cells use this to regulate the amount of organelles needed or not needed.

163
Q

Maturation of early endosomes containing endocytic vesicles to late endosomes occurs via?

A

“Multivesicular bodies”

164
Q

Late endosomes become endolysosmes & lysosomes by?

A

Fusing with preexisting lysosomes

Progressive acidification

165
Q

why does multivesicular bodies (MVB) shed vesicles?

A

to recycle material back to PM and Gradually convert into late endosomes by fusing with eachother / with other late endosomes

166
Q

what do proteins destined to join MVB get?

A

a mono-ubiquitin tag

167
Q

what do M6P receptor are for?

A

to interact with lysosomal enzymes. vesicles have them

168
Q

how downregulate transmembrane protein

A

they become multivesicular bodies inside endosomal compartment

169
Q

difference btw poly and mono ubiquitin tag

A

poly: brings proteins from the cytosol to the proteosome,
mono: tag transmembrane proteins to be engulfed within a lysosome

170
Q

residual body

A

anything that cant be digested, can remain in the cell as lipofuscin or be exocytosed

171
Q

autopahgy

A

ER envelopes old organelles (ie: mitochondria)

Fusion with a lysosome
lysosomal lipases break down all inner membranes;
lysosomal membrane protected by heavily glycosylated proteins & lipids

172
Q

lipofuscin?

A

pigmented lipids (“age pigments” accumulate in multiple organs)

173
Q

Mucopolysaccharidoses (MPS)

A

Defective degradation of GAGs (mucopolysaccharides)
MPS I – MPS VII
All Autosomal Recessive EXCEPT Hunter (X-linked)

174
Q

Hurler syndrome (MPS IH) inheritance pattern

A

autosomal recessive

175
Q

Hurler syndrome (MPS IH) mechanism

A

Defect alpha-L-iduronidase → Accumulation of GAGs:
Dermatan sulphate and Heparan sulphate
“hurLer alpha-L-iduronidase”

176
Q

Hurler syndrome (MPS IH) key words

A

alpha-L-iduronidase, Corneal clouding,

Hepatosplenomegaly, Coarse facial features, Hirsutism,

177
Q

Hurler syndrome (MPS IH) cell biology

A

2 GAGs: Dermatan sulphate and Heparan Sulphate
• Dermatan sulphate: Functions in coagulation, cardiovascular
disease, carcinogenesis, wound repair, and fibrosis
• Heparan sulphate: Regulates biological activities and has cell
receptors for viruses
• Hirsutism: Abnormal growth of hair on face and body
• Coarse: Not proportional

178
Q

Hurler syndrome (MPS IH) similar to which other disease symptoms?

A

I cell disease. (inclusion cell disease

179
Q

mode of inheritance of hunter syndrome (MPS II)

A

X-Linked

180
Q

hunter, hurler, I cell disease

A

know enzymes affected

181
Q

Hunter syndrome (MPS II) inherritance pattern

A

X-linked recessive

182
Q

Hunter syndrome (MPS II) mechanism

A

Defect iduronodate sulphatase → Accumulation of GAGs:

Dermatan sulphate and Heparan sulphate

183
Q

Hunter syndrome (MPS II) key works

A

“Hunters like to DATE their sulFATE”

IduronaDATE sulFATEase

184
Q

Hunter syndrome (MPS II) cell biology

A

“Hunters aim for the X so they can see later”
Similar to Hurler syndrome BUT
X-Linked NOT autosomal recessive
NO Corneal clouding
Later presentation (2-4yrs) and milder course (30’s)

185
Q

Chédiak-Higashi syndrome inherritance pattern

A

autosomal recessive (rare)

186
Q

Chédiak-Higashi syndrome mechanism

A

“cheDiak-Higashi: DAG HAR”
Mutated CHS1/LYST: → “DAG”
1) → Delayed fusion of phagosome with lysosome in
leukocytes
2) → Autophagocytosis of melanosomes in melanocytes
→ Albinism
3) → Granular defects in NK cells & platelets

187
Q

Chédiak-Higashi syndrome key words

A

“HAR” Hypopigmentation, Autophagosome, Recurrent infections

188
Q

Chédiak-Higashi syndrome cell biology

A

Hypopigmentation, Autophagosome, Recurrent infections

189
Q

Chédiak-Higashi syndrome cell biology

A

NK: Natural Killers contain cytosolic granules to aid in immune system

190
Q

what the pH in a peroxysome?

A

regular physiological pH

191
Q

number of enzymes in a peroxisome?

A

about 50

192
Q

what do peroxisome produce?

A

hydrogen peroxide.

193
Q

perexidase function

A

break down Hydro peroxide

194
Q

what signal a protein need to get into a peroxisome?

A

C terminal SKL (Ser-Lys-Leu) import signal (PTS1 signal)

195
Q

peroxins

A

import protein that recognize the SKL import signal. to aid proteins to get from the cytoplasm into the peroxisome

196
Q

biosynthetic function of peroxisomes

A 
Plasmalogen synthesis (ether phospholipid)
Bile acid synthesis (derived from cholesterol; occurs in liver) Lipid biosynthesis: Cholesterol & dolichol (also made by sER)
197
Q

degradative function of peroxisome?

A

VLCFA β-oxidation
Purine catabolism (xanthine oxidase)
H2O2

198
Q

only place that beta oxidation of very long chain fatty acids (VLCFA) can be broken down?

A

peroxisomes only

199
Q

xanthine oxidase finction

A

degrades nucleic acid purines A and G into uric acid that is secreted after

200
Q

allopurinol

A

xanthine oxidase inhibitor which results in hyperuricaemia (gout arthritis)

201
Q

plasmalogen

A

Membrane components of heart & brain

202
Q

Zellweger Syndrome mode of inheritance

A

autosomal recessive, congenital

203
Q

Zellweger Syndrome mechanism

A

Defected Peroxin does not recognize SKL ! failure to import peroxisomal enzymes ! empty peroxisomes ! peroxisome deficiency: VLCFA
accumulation glial cell membrane ! abnormal brain development ! neuronal migration defects & hypomelination (lack of plasmalogen); accumulation of VLCFA in liver !
hepatomegaly & liver failure; lack of bile acids ! decreased fat absorption ! decreased ATP! muscle weakness.

204
Q

X-linked Adrenoleukodystrophy (XALD) mechanism?

A

Defect in transport of VLCFA into peroxisome ! defective breakdown of
VLCFAs ! accumulation of VLCFA: brain (glial cells) ! myelin breakdown; adrenal cortex! adrenal atrophy

205
Q

mitochondria innermembrane strrcture

A

permeable and allow free diffusion of small molecules and ions

206
Q

functions of mitochondria

A

atp production, and apoptosis

207
Q

number of mitochondria in a cell is related to what

A

the cell’s need for energy. more active cells will have more.

208
Q

mitochondria innermembrane

A

impermeable to most molecules. has cristae to increase surface area

209
Q

most important feature of inner membrane of mitochondria

A

the impermeability which allows for gradient

210
Q

where in the mitochondira is atp produced?

A

in the matrix, even though the atp synthase is in the inner membrane

211
Q

cardiolioin importance in the inner membrane?

A

lipid that makes is impermeable.

212
Q

properties of cardiolipin present in the inner membrane of mitochondria

A

it makes up to 20% of the inner membrane, it has double phospholipid (4 tails) it is made in the mitochondria unlike the others that are imported

213
Q

Barth syndrome

A

X-linked cardiolipin synthesis disorder
Cardiomyopathy
Generalised muscle weakness & chronic fatigue
Neutropenia

MCB (6 decks)

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