Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CELL 301 > Section 1 - ROS part 1 > Flashcards

Section 1 - ROS part 1 Flashcards

1
Q

ROS stands for _______

A

reactive oxygen species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

ROS are made inside _____? because?

A

-inside cells
-because oxygen is highly reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

ROS definition

A

oxygen-containing molecules that are short-lived and highly reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

3 types of ROS

A

-superoxide anion
-hydrogen peroxide
-hydroxyl radical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

superoxide anion + formed from ______

A

O2.-, oxygen + e-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

hydrogen peroxide + formed from ______

A

-H2O2
-superoxide anion (O2.-) + H+ = HO2., 2HO2. = H2O2 + O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

hydroxyl radical + formed from _____

A

-HO.
-superoxide anion (O2.-) + H2O2 = O2 + OH- + OH.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Harman (1950) hypothesized _____

A

Free Radical Theory of Aging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Free Radical Theory of Aging mainly claims that _____

A

-increasing ROS = increase in oxidative stress = increase aging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Free Radical Theory of Aging method

A

-irradiated people with radiation had an increase in ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Free Radical Theory of Aging observed that ______

A

older animals from different species has more ROS than younger animals (consistent phenomenon)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Free Radical Theory of Aging suggests that lifespan differences between different species is due to _______

A

different mechanisms against ROS, which cause aging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Location of ROS production? why?

A

-mitochondria
-it is the location of oxygen consumption in the cell due to oxidative phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Mitochondria Metabolism summary

A

-matrix: citric acid/krebs cycle produces NADH which donates e- to electron transport chain in inner membrane.
-intermembrane space: electron transport chain pump H+ into space & H+ enters back into matrix through ATP synthase. flux of H+ produces ATP. e- enters matrix again to reduce O2 in matrix to make H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

pH of mitochondrial intermembrane space

A

low pH (high conc of H+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

pH of mitochondrial matrix

A

high pH (low conc of H+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

cytochrome c oxidase complex does what?

A

moves H+ into the intermembrane space (part of oxidative phosphorylation machinery)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

artificial liposomes with cytochrome c oxidase do what in the presence of oxygen?

A

-consumes oxygen and moves H+ into the medium (pH of the medium drops rapidly with a gradually recovery as oxygen is depleted)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

charge of mitochondrial intermembrane space

A

positive charge (protons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

charge of mitochondrial matrix

A

negative charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

TMRM is what?

A

fluorescent compound that follows negative charge (often used to assay mitochondrial membrane potential )

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

MMP (def.)

A

mitochondrial membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

TMRM & mitochondria interaction

A

TMRM follows negative charge found inside the mitochondrial matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

other methods used to assay mitochondrial membrane potential

A

fluorimeter, microscopy or flow cytometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Oligomycin is what?

A

a drug that binds ATP synthase and blocks the proton channel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Oligomycin + TMRM signal

A

-increase TMRM signal because matrix is more negative as H+ flow into the matrix through ATP synthase is blocked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

FCCP does what?

A

-uncoupler that acts as a ionophore
-transports protons into matrix, disrupting ATP synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

FCCP + TMRM signal

A

-decrease TMRM signal rapidly because matrix is less negative as H+ enters the matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

______ allows for precise localization of fluorophores with __________

A

-Scanning confocal laser microscope
-minimal light incidence over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Why use scanning confocal laser microscope with fluorophores?

A

-high amount light destroys the fluorophores leading to bleaching; needs a low amount of incident light to prevent destroying fluorophores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

byproducts of destruction of fluorophores

A

ROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

activity that increases cell ATP demand

A

-transport mechanism
-protein folding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

increased ATP demand + TMRM signal

A

-decrease TMRM signal as H+ enters matrix to make ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Calcium controls _____ in mitochondria

A

pore opening (opens pore)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

recoverable Ca2+ load + TMRM signal

A

-decrease TMRM signal as H+ enters matrix to make ATP
-calcium removed over time, common in muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

excessive Ca2+ load + TMRM signal

A
  • apoptosis
  • decrease TMRM signal slightly as H+ enters matrix to make ATP until it reach permeability transition (loss of mitochondria membrane potential) and then decrease rapidly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

PTPC stands for

A

permeability transition pore complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

PTPC does what?

A

serves as a gatekeeper for the mitochondrial membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

problems with PTPC leads to ______

A

diseases like muscle dystrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

PTPC is formed by ______

A

ATP synthase under the influence of Ca+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

permeability transition is when the mitochondria does what?

A

mitochondria loses ability to hold H+ in intermembrane space and subsequently can’t creates ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

ROS and effect of PTPC

A

-hydrogen peroxide opens PTPC
-loss of membrane potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

level of ____ affects membrane permeability of mitochondria

A

oxidative stress and Ca+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

increase oxidative stress/Ca+ = ______ + effect on TMRN

A

increase membrane permeability of mitochondria/ open pore -> TMRN staining is lost

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

To understand how a mechanism works, you need to _____

A

identify and characterize the proteins or molecules executing it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Permeability Transition Pore Complex is a ______ (descr.)

A

600kDa multiprotein complex on the inner membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

PTPC regulates _____

A

exchange of ions and ATP between matrix and cytosol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

ROS and Ca+ can lead to _____

A

abnormal PTPC opening, leading to mitochondrial swelling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

PTPC opening reduces production of _____

A

ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

PTPC opening is promoted by ______

A

sustained calcium, pro-oxidants (ROS), nucleotide depletion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

PTPC opening is inhibited by ______

A

-Bcl2, BclXL, high ADP/ATP, cyclosporin A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Bcl2 proteins are _____ & function in mitochondria

A

-anti-apoptotic
-closes pore = ATP production continues (no apoptosis)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

PTPC open pore & effect on ATP production

A

-decrease ATP production (apoptosis started)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

ROS are _____ that modify _______ similar to _____

A

-cellular signalling molecules
-post-translationally many substrates
-phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

ROS modification of proteins crosstalks with ______

A

lipid modification (ex. palmitoylation)

56
Q

ROS modification: oxidation typically _____

A

affect cysteine residues (ex. forms disulfide bonds)

57
Q

result of ROS modification is ______ and it is very ______

A

-oxidation
-difficult to determine experimentally

58
Q

ROS opens PTPC by ______

A

post-translationally modifying the regulatory protein cyclophilin D

59
Q

cyclophilin D has this type of activity?

A

peptidyl-prolyl isomerase activity (changes structure of proline residues)

60
Q

ROS modifies cyclophilin D on _____

A

Cys 202 (humans)/ 203 (other species)

61
Q

Normal cell: cyclophilin D

A

Cys202 is S-palmitoylated

62
Q

Cell under ischaemia (low oxygen): cyclophilin D

A

Cys202 is oxidized on sulfur residue with ROS

63
Q

oxidized Cys202/203 of CyD effect on PTP

A

opens PTP

64
Q

Transfection allows for the easy ____

A

introduction of foreign DNA sequence

65
Q

Transfection methods (2)

A

-lipid treatment (using liposome to allow DNA to enter cell)
-electroporation (high voltage shocks to allow DNA to enter the cell)

66
Q

Problem with transient transfection

A

not all cells will express the protein; temporary

67
Q

Transient transfection vs. CRISPR/Cas 9

A

-temporary vs. permanent/may cause cell to adapt

68
Q

Mice with knockout cyclophilin D characteristics (3)

A

-smaller myocardial infarction
-reduction of neuroinflammation
-resistance to neurodegeneration

69
Q

Knockout cyclophilin D mice shows that _____

A

abnormal mitochondria activity plays a crucial role in disease progression

70
Q

mutation of cys202/203 of cyclophilin D effect

A

inhibits mPTP opening and improves cell viability

71
Q

proteins loaded with studied protein in western blot or other experiments serve as ______

A

indications that proteins are expressed at the same level in knockout and wildtype cells

72
Q

Ionomycin does what?

A

dissipates MMP; Ca2+ permeabilizing drug, increase Ca+ levels (calcium opens PTP)

73
Q

ionomycin + cyclophilin D that can’t be oxidized

A

-ionomycin does not dissipate mitochondrial membrane potential as efficiently

74
Q

cyclosporin A does what?

A

a drug that inhibits PTP by interfering with CypD activity

75
Q

cyclophilin D does what?

A

activates permeability transition (opens mPTP opening)

76
Q

In the presence of the mutant CypD (cyclophilin D), CSA (cyclosporin A) ______

A

is no longer able to alter PTP opening

77
Q

Ionomycin does not dissipate MMP well if ______

A

Cys203(sulfur) that is expressed cannot be oxidized

78
Q

max flux of PTP requires ______

A

binding of cyclophilin D (oxidized) and presence of ROS , Ca++

79
Q

ROS modulate mitochondrial energy output by _______

A

altering the open state of PTP

80
Q

how ROS is measured in vivo?

A

-H2DCFDA (outside cell) enter lipid bilayer and is transformed by esterases into H2DCF
-ROS reacts with it to produce fluorescent DCF probe (measured by fluorescence microscopy and flow cytometry)

81
Q

Advantages of flow cytometry to confocal microscopy

A

-precise quantification of fluorophores
-can observe live cell biological processes
-1D and 2D flow cytometry

82
Q

level of ROS is measured by ____

A

fluorescent DCF probe

83
Q

amount of fluorescent DCF probe is proportional to _____

A

amount of ROS

84
Q

level of ROS in healthy cells/ diseased cells

A

-can high or low (doesn’t support Free Radical Theory of Aging)

85
Q

ROS-induced ROS release (def.) in cardiac myocytes

A

-damaged mitochondria from illumination produces ROS then ROS damages another mitochondria, leading ROS release (propagation of mitochondria damage)

86
Q

ROS-induced ROS release affects ____

A

mitochondrial ATP production by affecting MMP (as seen in TMRM signal)

87
Q

ROS move from mitochondria to mitochondria, doing what?

A

disrupting mPTP

88
Q

Closed pore effect on ROS production

A

ROS production is slow

89
Q

Speed of OXPHOS/ATP production effect on ROS production

A

ROS production is fast

90
Q

ROS scavenging (the elimination of ROS) involves ____

A

multiple enzymes like SOD1 and SOD2

91
Q

_____ (ALS) is one of the more prevalent _____.

A

-Amyotrophic lateral sclerosis
-adult-onset neurodegenerative diseases

92
Q

ALS disease characterization

A

-progressive injury and death of lower motor neurons in the spinal cord and brainstem, and upper motor neurons in the motor cortex
-rapid progression
-survival only 2-3 years after symptoms appear

93
Q

ALS disease mutations

A

-20% familial ALS caused by mutaions in copper/zinc superoxide dismutase (Cu/Zn SOD, SOD1) - majority of cases are not familial

94
Q

mutations in SOD1 are not ____

A

the cause of most cases of ALS

95
Q

p66Shc adaptor protein controls what? However, futher studies show that it is not a _____

A

-oxidative stress response and lifespan in mammals
-lifespan gene

96
Q

p66 is a ____

A

mitochondrial protein

97
Q

loss of p66 does what?

A

-protected from paraquat death
-knockout mice live longer & protected from aging

98
Q

p66 does what?

A

sequesters cytochrome c after the induction of apoptosis, causing an increase in ROS production because electrons are no longer passed to complex IV of electron transport chain

99
Q

after p66 sequesters cytochrome c and increases ROS production, ______ ensue

A

induced permeability transition and apoptosis ensue

100
Q

Why are p66 ko mice protected from aging?

A

-p66 can no longer induce apoptosis through amplification of ROS production that promotes aging

101
Q

p66 ko mice are protected from ____ (2) but have ____

A
  • obesity and cancer
    -defective cold adaption (lack uncoupling protein function for thermogenesis)
102
Q

ROS production at complex I and II happens when ____

A

the steady oxygen supply is lost and the flow of electrons through electron transport chain is disrupted (traffic jams)

103
Q

ROS produced at complex I and II do what?

A

chemically modify proteins close to mitochondria

104
Q

HyPer7 GFP-based probe does what?

A

detect H2O2 (that leads to ROS) within mitochondria upon injury and on the leading edge of moving cells

105
Q

antimycin does what?

A

blocks mitochondrial complex III

106
Q

mitochondria + antimycin

A

increase ROS production

107
Q

mitochondria, when undergoing forced respiration in the presence of galactose (instead of glucose/glycolysis) do what?>

A

increase ROS production

108
Q

mitochondria produce ROS if ______ or if _____

A

-their electron transport chain is impaired (blocking ETS)
-cellular energy levels drop (blocking glycolysis)

109
Q

this is not true but theoretically, deletion of SOD2/SOD1 should ____

A

induce mitochondrial ROS and decrease lifespan

110
Q

KO of SOD2 does what?

A

-decreases oxygen consumption, decreasing mitochondrial activity
-increase lifespan in C. elegans

111
Q

isp-1 is what?

A

an ortholog of human ubiquinol-cytochrome c reductase which is involved in ETC

112
Q

KO of isp-1 does what?

A

increase survival more than sod-2 KO, while decreasing mitochondrial activity

113
Q

KO of isp-1 and sod-2 together do what?

A

decrease mitochondrial function to the point of no survival

114
Q

the KO of isp-1 and sod-2 shows that a bit of ____

A

ROS (oxidative stress) is good as it turns on the cell protective mechanism, allowing for good cellular function

115
Q

mitochondrial ROS perform a dual function as _____

A

signaling molecules that can also lead to life span extension via activation of antioxidant defense mechanisms

116
Q

in KO SOD organisms, antioxidant systems are ____

A

more active so higher levels of ROS are needed before reaching oxidative stress

117
Q

over expression of ___ extends life span but deletion of ___ has often no. effect in C. elegans with the exception of _____

A

-catalase
-SOD
-SOD-2

118
Q

substrates of ROS include PTPC and ___

A

key cellular signalling proteins

119
Q

proteins controlled by ROS are often ____

A

sulfenylated (like phosphorylation)

120
Q

sulfenylation is a ____

A

post-translational modification (oxidized thiol)

121
Q

How to detect sulfenylated proteins?

A

-n-ethylmaleimide/iodoactemide block other thiols
-sulfenylated proteins were tagged with dimedone and dettected with an antibody

122
Q

signal of oxidized cys increases when?

A

incubated at low temp

123
Q

VCL is what?

A

vinculin western signal (loading control)

124
Q

N-acetylcysteine is what?

A

-antioxidant that will desulfenylate non-specifically)

125
Q

UCP1 is what?

A

-a mitochondrial transmembrane protein that decrease proton gradient developed by OXPHOS

126
Q

UCP1 (uncoupling protein 1) is involved in _____

A

non-shivering thermogenesis in brown adipose tissue

127
Q

in the presence of antioxidants, body temp ____

A

drops because UCP (which is involved in thermogenesis) is not oxidized (sulfenylated) by ROS

128
Q

Sulfenylated UCP changes focus of mitochondria on _____ rather than _____

A

-heat generation at UCP (leak)
-work at mPTP/ATPase (work)

129
Q

when oxidized/sulfenylated, UCP1 uncouples the ______ and causes _____

A

-mitochondrial proton gradient
-mitochondrial heat production to spike

130
Q

temperature of mitochondria

A

50 C

131
Q

Mito Thermo Yellow allows us to _____, with decrease in fluorescence meaning _____

A

-measure temperature within cells
-temp increase

132
Q

peroxisomes make heat via _____ due to the lack of _____

A

-B-chain oxidation of fatty acids which produce ROS
-respiratory chain

133
Q

hypoxia and hyperoxia conditions produce excess _____

A

ROS

134
Q

normoxia conditions still has ___

A

some ROS as it is needed for cellular activity

135
Q

under really low levels of oxygen, ROS production is ___

A

blunted

136
Q

Different tissues within the body have different _____ so mitochondria in vivo doesn’t ____

A

-oxygen supplies and demand
-have as much oxygen as in vitro

CELL 301 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions