Chapter 5 Flashcards

1
Q

what other organelle is involved in the fission of mitchondria?

A

the ER. wraps around the mito and acts as a noose. fission facilitated by DRP1 proteins

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2
Q

T/F: mitochondria contain cholesterol

A

false, they contain cardiolipid, a disphophatidyl glycerol

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3
Q

role of cardiolipid

A

a di phosphatidyl glycerol that facilitates protein complexes involved in ETC and ATP synthesis

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4
Q

which of the two membranes in a mitochondria have more proteins

A

the inner mito membrane has more proteins

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5
Q

what enzymes are contained in the outer mito memberane

A

enzymes involved in trytophan synthesis and epinephrine oxidation and FA elongation

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6
Q

why is the outermembrane so permeable compared tot he inner membrane?

A

the outermembranes have porin channels that allow flow of ATP, NADH, coA etc

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7
Q

Where in the mito is the DNA and the ribosomes

A

in the matrix

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8
Q

why is mito DNA important

A

it codes for 2rRNAs and 22tRNAs responsible for mito protein synthesis

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9
Q

mitochondrial RNA is synthesized by ____ polymerase

A

RNA polymerase

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10
Q

3 steps of cell resp for aerobes

A

1) glycolysis
2) Krebs
3) ETC

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11
Q

2-carbon acetyl coA is ____ with oxaloacetate to form citrate

A

condensed

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12
Q

ketogenic amino acids

A

amino acids that are broken down into acetyl coA

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13
Q

glucogenic amino acids

A

AAs that are broken down into Krebs intermediates

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14
Q

what does the glycerol phosphate shuttle do

A

converts cytosolic NADH from glycolysis into the inner membrane by converting it into FADH2

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15
Q

two methods of cytosolic nadh entering the inner membrane to go through ETC

A

1) malate aspartate shuttle

2) glycerol phosphate shuttle

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16
Q

oxidative phosphorylation

A

when ATP formation is driven by energy that is released from electrons removed during substrate oxidation

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17
Q

good oxidizing agents have a ____ electron affinity

A

high electron affinity. oxidizing agents will oxidize a substance because it wants its electrons

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18
Q

redox reactions are accompanied by a ____ in free energy, why?

A

decreased in delta G. as electrons get passed, they lose energy, you cannot pass electrons to create a higher energy product spontaneously

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19
Q

electron carriers in the ETC complex I have a _____ redox potential than complex IV

A

complex I has a lower redox potential. Complexes are in order of increasing electron affinity (higher and higher electron affinities)

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20
Q

5 types of electron carriers

A

1) flavoproteins
2) cytochromes
3) Fe-S
4) Three Cu Atoms
5) ubiquinones

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21
Q

what is a flavoprotein and how many electrons can they accept? what vitamins are they derived from?

A

flavoprotein is an electron carrier that is a poly peptide bound to FMN or FAD. derived from B2. can accept 2 e-

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22
Q

Cytochromes contain a ____ prosthetic group. how many e- can they carry? how many types of cytochromes?

A

heme prosthetic group, can carry one e- (fe3+ to 2+), 3 types of cytochromes (a,b,c)

23
Q

3 Cu atoms. How many electrons can they hold?

A

1 e=

24
Q

Ubiquinone is ____ soluble. how many electrons does ubiquinone hold? What is it made of?

A

its lipid soluble, can hold 2 e-. Made of 5 isoprenoid rings

25
Q

What are Fe-S electron carriers? how many e- can theyhold?

A

Fe-s is an electron carrier with iron covalently bonded to inorganic sulfer. can hold one e-.

26
Q

how are Fe-S electron carriers linked to their specific protein complexes?

A

through cystein residues

27
Q

how is the sequence of Fe-S electron carriers in the ETC determind

A

using inhibitors

28
Q

example of an FMN flavoprotein

A

Quinone–>semiquinone—>hydroquinone

29
Q

redox states of ubiquinone

A

ubiquinone —>ubisemiquinone —> ubiquinol

30
Q

alternative name for complex I

A

NADH dehydrogenase

31
Q

name for complex III

A

cyt c reductase

32
Q

name for complex IV

A

cyt c oxidase

33
Q

why are complexes called proton pumps?

A

because it uses active transport in the form of electrons to pump protons across the gradient

34
Q

how does cyt c oxidase (complex IV) pump protons across the gradient?

A

it relies on the energy released by oxygen reduction to drive conformational change of the pump to push protons across

35
Q

what are substrate protons?

A

protons that get used by complex IV but do not get pumped across the gradient. these protons are consumed in complex IV’s reactions.

complex 4 uses 8 protons in total:

  • 4 as substrate protons
  • 4 that are pumped across the membrane

both types contribute to creating an electrochemical gradient

36
Q

2 components to the proton gradient. What do these components create?

A

1) the concentration gradient, creating a change in pH
2) the separation of charge across the membrane creates an electric potential

both components create the proton motive force

37
Q

chemiosmotic theory

A

generation of ATP via ATP synthase, which functions by coupling H+ flow/translocation that is powered by e- transfer down the electron transport chain

38
Q

how does DNP uncouple glucose oxidation with ADP phosphorylation?

A

it is lipid solluble and engulfs a proton, allowing protons to move back into the cell through its gradient. No atp is formed during this.

39
Q

how does rotenone block electron transport?

A

it keeps Fe-S electron carrier in complex I reduced, so no electrons can be transfered to ubiquinone.

40
Q

how does antimycin A block electron transport

A

inhibits the oxidation of ubiquinone. electrons cannot be transfered to complex III

41
Q

Why is cyanide lethal?

A

because it blocks the ETC, block complex IV at the site where O2 is supposed to accept e-

42
Q

how can you remove the F1 particles of ATP synthase for analysis?

A

1) sonification to expose ATP synthase heads

2) treat with Urea

43
Q

bindning change mechanism

A

energy released by movement of protons does not direcly drive ADP phosphorylation, but CHANGES THE BINDING affinity of the active site for ATP production

44
Q

how many active sites on F1

A

three, the beta subunits)

45
Q

three statees of F1beta subunts

A

1) L state; loose state, reactants loosely held
2) tense state: reactants are smooshed together (forms atP)
3) open state: low affinity for nucleotides, ATP is released.

46
Q

ATP is synthesized by _____ catalysis

A

rotational catalysis: stalk rotates relative to the alpha and beta subunits in the F1 head

47
Q

the pmf and electrical energy stored in the proton gradient is ______ into mechanical energy (rotation of F0 base and stalk), which makes ATP

A

transduced

48
Q

___ degree rotation creates one atp

A

120 degree rotation of the stalk creates one atp

49
Q

how can you directly observe rotational catalysis?

A

by tagging the gamma subunit (stalk) with a fluorecent actin filament. attach the filament by switching a serine residue to a cysteine of the stalk

50
Q

what amino acid in Fo complex is required for the protons to enter the c subunit disk?

A

Asp61 is present in the C subunit, binding the protons. everytime a proton binds, the ring rotates 30 degrees

51
Q

for every ATP produced, how many H+ ions need to be moved?

A

4 get pumped back into the matrix

52
Q

function of adenine nucleotide translocase

A

transport ATP from matrix to the cytosol for cellular activities, exchanging for ADP

53
Q

functino of peroxisomes

A

site of H2O2 synthesis and degradation