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cell bio > Mitochondria and Secretion > Flashcards

Mitochondria and Secretion Flashcards

1
Q

what are the organelles in a eukaryotic cell?

A 
Nucleus
Endoplasmic reticulum
golgi apparatus
cell membrane
lysosome
secretory vesicles
mitochondria
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2
Q

what are the sub compartments of mitochondria?

A 
outer membrane
inner membrane
intermembrane space
matrix- 2/3 or 67% of mitochondria proteins are here
crista
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3
Q

describe respiration cycle in mitochondria

A

mitochondria converts oxygen to water. Citric acid cycle forms CO2 and ADP converts to ATP for energy

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4
Q

what is the net result of the citric acid cyle?

A

1 GTP
1 FADH2
releases 2 CO2
3 NADH

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5
Q

the electron transfer is coupled to?

A

pumping H+ into the intermembrane space

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6
Q

what is oxidative phosphorylation?

A

conversion of ADP to ATP

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7
Q

The ATP synthesis is coupled to?

A

pumping H+ into the matrix

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8
Q

what does glycolysis yield?

A

2 ATP

2NADH

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9
Q

What does pyruvate converted to 2 acetyl-CoA yield?

A

2 NADH

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10
Q

What does the citrate cycle yield?

A

2x
1 FADH2 2 FADH2
3 NADH 6 NADH
1 GTP 2 GTP

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11
Q

what is the total number of ATP produced by glycolysis and the citric acid cycle for 1 molecule of glucose?

A

~32 ATP

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12
Q

mitonchondrial dna is located where?

A

the inner membrane on the matrix side

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13
Q

what is the d-loop in human mitochondrial DNA?

A

its the site where mtdna replication and transcription starts

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14
Q

what are the diseases with links to mutations in mitonchondrial dna?

A 
cancer
cardiovascular diseases
diabetes mellitus
neurodegenerative diseases
premature aging syndrome
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15
Q

what are the four locations proteins in mitochondria are at?

A

outer membrane protein
intermembrane protein
inner membrane space protein
matrix protein

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16
Q

what does a mitochondrial protein need to be in order to be imported?

A

the cytosolic precursor form of a mitochondrial protein must be in an unfolded conformation

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17
Q

protein import into the mitochondrial matrix requires?

A

signal sequence
substrate needs to be unfolded
membrane potential across the inner membrane
ATP inside the matrix

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18
Q

what does mitochondria store?

A

it stores calcium Ca2+ which is important for muscle contraction

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19
Q

what are the type of mutation in mitochondrial DNA?

A

point mutations
depletions
depletion of mtDNA

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20
Q

how are gene products synthesized in the cytosol imported into the mitochondria?

A

they are post translationally imported

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21
Q

where are many mitochondrial targeting signals located at?

A

at the N-terminus and form an amphipathic helix

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22
Q

what are psitively charged amino acids?

23
Q

what are the matrix targeting presequences?

A 
NH2 terminal
20-80 amino acids
cleavable or uncleavable
degenerate sequence that is rich in basic amino acids
forms aphipathic alphahelix
24
Q

what are the inner membrane / intermembrane space presequences?

A

NH2 terminal presequence directs import to matrix

internal stop transfer sequence that determines localization to outer membrane or inner membrane

25
what are the 2 major protein complexes required for protein import and sorting process?
the translocase of the outer membrane (TOM) | the translocase of the inner mebrane (TIM)
26
what is the role of mitochondrial dna?
produce enzymes and proteins needed for the many pathways that produce energy in the mitochondria. regulates cellular metabolism, apoptosis, and oxydative stress control
27
how are proteins imported into mitochondria and targeted to their final destinations?
proteins have signal sequence, recognized by chaperone called mitochondrial stimulation factor (MSF) MSF targets the protein to a receptor in the mitochondria outer membrane. and through the intermembrane space to the inner mitochondrial membrane (e.g. some proteins of the electron transport chain) and the matrix.
28
what is the role of mitochondria in apoptosis?
Permeabilization of mitochondrial membranes is main feature in apoptosis. Bcl-2 and Bcl-XL stabalize outer membrane. Bax and Bak de-stabilize outer membrane. when barrier of outer mitochondrial membrane is lost many apoptotic mitochondrial proteins like cytochrome c are released into the cytosol and activate enzymes like protease or capspases to induce cell death.
29
what is the role of mitochondria in apoptosis?
Permeabilization of mitochondrial membranes is main feature in apoptosis. Bcl-2 and Bcl-XL stabalize outer membrane. Bax and Bak de-stabilize outer membrane. when barrier of outer mitochondrial membrane is lost many apoptotic mitochondrial proteins like cytochrome c are released into the cytosol and activate enzymes like protease or capspases to induce cell death.
30
what is endosymbiosis?
bacterial origin of mitocondria
31
what are the physiological roles of mitochondrial Ca2+ ?
stimulate and control rate of oxidative phophorylation induce mitochondrial permeability transition and apoptosis modify theshape of cytosolic Ca2+ pules or transients (e.g. muscle contractoin)
32
what are free ribosomes?
free ribosomes synthesize proteins for use within the cell
33
what are membrane bound ribosomes?
bound ribosomes synthesize proteins for export from the cell or for use in lysosomes
34
what are microsomes?
vesicles from ER membrane
35
describe cell free protein synthesis with no microsomes present
no incorporation into microsomes; no removal of signal sequence
36
the lysosome has what pH?
acidic pH
37
the protein import from a ribosome to the ER is ?
co-translatational
38
what is glycosylation of proteins?
monitoring the status of protein folding in the ER In the ER, glycosylation is used to monitor the status of protein folding, acting as a quality control mechanism to ensure that only properly folded proteins are trafficked to the Golgi.Dependent on the linkage of the oligosaccharide to the amino acid side chain of the protein there are two major types of glycosylation: N- and O-glycosylation.
39
what does mtDNA encode?
respiratory chain complexes, ribosomal RNAs , transfer RNAs
40
the attachement of the glycosylation chain to secreted proteins occurs in ?
the lumen of the endoplasmic reticulum
41
what is the signal recognition particle?
a ribonucleoprotein, that recognizes the signal sequence of a protein being translocated across the ER membrane
42
posttranslational translocation
protein first synthesized in cytosol and then transported into the ER.
43
cotranslational translocation
translocation occurs at same time as protein is being made
44
how are proteins targeted to the outer side of the ER
by signal recognition particle (SRP)
45
how are proteins imported into the ER?
by signal sequence. Proteins are fed into the ER during translation if they have an amino sequence called a signal peptide Signal recognition particle (SRP)
46
how are protein modified and folded in the ER?
newly synthesized protein entering the endoplasmic reticulum (ER) undergoes a series of modifications and encounters a number of molecular chaperones and folding enzymes that all together assist its proper folding and subsequent release from the ER.
47
what is quality control?
ensuring that misfolded protein do not leave ER
48
whats the function of endo- and exocytosis?
Endocytosis is the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane, and bringing it into the cell. Exocytosis describes the process of vesicles fusing with the plasma membrane and releasing their contents to the outside of the cell
49
why are vesicles coated?
helps move vesicle from 1 compartment to another induces exocytosis and endocytosis to induced invagination and endocytosis by clathrins The transport of proteins and lipids between distinct cellular compartments is conducted by coated vesicles. These vesicles are formed by the self-assembly of coat proteins on a membrane, leading to collection of the vesicle cargo and membrane bending to form a bud.
50
function of glycosylation of proteins in ER?
protect from uncontrolled digest retain them in the ER transports to specific organelles In the ER, glycosylation is used to monitor the status of protein folding, acting as a quality control mechanism to ensure that only properly folded proteins are trafficked to the Golgi.
51
what is V-snare?
vesicle specific
52
what is t-snare?
target specific
53
KDEL receptors retrieve?
ER resident proteins. KDEL is an ER retention signal

cell bio (9 decks)

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