Unit 4: Chapter 21 Flashcards
Protons will move back down into the matrix down electrochemical gradient though enzyme _______
ATP Synthase
ATP Synthase
Catalyzes ATP synthesis from proton motive force and formation of cristae
Cristae
Area where protons ready access to ATP synthesis
Energy released from proton gradient are used for
phosphorylation of ADP to ATP
Chemiosmotic coupling
proton concentration gradient generated by the electron transport chain, is what drives ATP production via ATP synthase
Oxidative phosphorylation depends on creation of ______________
proton gradient
Proton gradient is coupled to porduction of ATP in ________________
aerboic metabolism
pH of mitochondrial matrix is ____ than pH of intermembrane space
higher
(less protons as they are being pumped out into intermembrane space)
pH of intermembrane space is _____ than pH of mitochondrial space
lower
(more protons being pumped into intermembrane space)
_____ powers the synthesis of ATP
Proton gradient
Proton motive force
- Proton gradient generates by oxidation of NADH and FADH 2
- PMF = chemical gradient and charge gradient
ATP Synthase structure
2 units:
1. F1 componet (catalytic)
2. F0 componet (proton conducting)
F0 componet of ATP Synthase
Proton conducting
Contains proton channels and embedded in inner mitochondrial membrane
F1 componet of ATP Synthase
Catalytic site
Contains active sites and protrudes into mitochondrial matrix
ATP Synthase binds to one another to form _____ which then oligomerize –> oligomers contribute to fomration of _____
dimers; cristae
ATP Synthase contains __ active sites located on ___ beta strands
3 ; 3
What connects the F1 and F0 componet of ATP synthase?
Gamma (Y) subunit
Each beta catalytic subunit is distinct in conformation for each subunit and interacts different with
Gamma (Y) subunit
After proton pump from matrix to intermembrane space, protons return back to the matrix by _______
ATP Synthase
ATP synthesis from ATP synthase occurs
matrix
Protons flow from ATP synthase leads to release of
tightly bound ATP
Three catayltic beta subunits of F1 componet can exist in
3 conformations
O (open form) of ATP Synthase
Nucleotides can bind or be released from beta subunit
L (loose) form of ATP Synthase
Nucleotides are trapped in beta subunit
T (tight) form of ATP Synthase
ATP is synthesized from ADP and Phosphate
T form to O form:
releasing ATP
L form to T form:
produces ATP
The ___ accounts for synthesis of ATP in response to proton flow
binding change mechanism of ATP synthase
True or False: no 2 subunits are ever in same conformation of ATP synthase
True
Each subunit of ATP synthase cycles through
the 3 conformations
____ in proteins are crucial in synthesis of ATP in mitochondria
Conformational changes
Shuttles
Transfer electrons produced from cytoplasmic NADH by glycolysis so it can enter mitochondria
In muscle, electrons from cytoplasm of NADH enter ETC in mitochondria by
glycerol phosphate shuttle
Glycerol phosphate shuttle
From muscle glycolysis
1.5 ATP produced for each cytosolic NADH (1 less than normal) uses complex II
NADH (cytoplasm) donates electron to E-FAD (mitochondria) –> NAD+ (cytoplasm) and E-FADH2 (mitochondria)
Glycerol 3 phopshate is produced by the reduction of
DHAP: Dihydroxyacetone phosphatate
In heart, kidney , and liver, electrons from cytoplasmic NADH are used to generate mitochondrial NADH through
maltate aspartate shuttle
maltate aspartate shuttle consists of:
2 membrane transporters and 4 enzymes
Maltate aspartate shuttle
NADH (cytoplasm + H+ gives e- to NAD+ (mitchondria)
–> NAD+ (cytoplasm) + NADH (mitochondria)
2.5 ATP produced for each cytosolic NADH
Oxaloacetate is reduced to _____ in maltate aspartate shutte by _____
maltate; cytosolic maltate dehydrogenase
Entry of ADP into mitochondria is coupled to
exit of ATP
ATP-ADP translocase
Enables exchange of cytoplasmic ADP for mitochondria ATP powered by proton motive force
Mechanism for ATP ADP translocase
- ATP in cytoplasm allows for ADP to be made and binds to translocase
- Eversion
- ADP released into matrix
- ADP in matrix used to make ATP
- Eversion
- ATP released into cytoplasm
Cytoplasm and nucleus have more ___ than mitochondria
ATP
ATP synthasome
ATP–ADP translocase, the phosphate carrier, and the
ATP synthase form complex
________ is continous supply of ADP for the cytosol which is entered through ATP ADP translocase to produce ___ and return back to cytoplasm
ATP synthesized in mitochondria; ATP
Mitochondrial Transporters
allow metabolic exchange between cytoplasm and mitochondria
How is cellular respiration regulated?
By need for ATP
Complete oxidation of glucose yield ___ molcules of ATP
30
Of the 30 molecules of ATP from complete oxidation of glucose ___ are from oxidative phosphorylation
26
When cells need and use little energy
HIgh ATP, low ADP = High ATP/ ADP ratio
High NADH, low NAD+ = High NADH/ NAD+ ratio
When cells need and use more energy
low ATP, high ADP = low ATP/ ADP ratio
low NADH, high NAD+ = low NADH/ NAD+ ratio
Rate of oxidation is determined by
the need for ATP
electrons do not flow through ETC unless ___ is available
ADP so it can be converted into ATP
Acceptor/ respiratory control
regulation of oxidative phosphorylation by ADP
(ex of control of metabolism by energy change)
Uncoupling protein 1 (UCP 1)
generates heat by permitting influx of protons into the mitochondria without synthesis of ATP
Uncoupling protein
Protons are not in intermembrane space, but move back into matrix so ATP synthesis and proton gradient can not couple
Inhibitors of Oxidative phosphorylation
- Inhibition of ETC prevents oxidative phosphorylation by inhibiting formation of PMF
- Inhibition of ATP synthase by inhibiting proton flow prevents electron transport
- inhibition of ATP ADP translocase prevents oxidative phosphorylation
Uncouplers
Carry proteins across inner mitochondria so ETC can function, but ATP synthesis does not occur since proton gradient can never form
P/O Ratio
Ratio of ATP produced by oxidative phosphorylation to oxygen atoms consumed in electron transport
P/O = ? when NADH is oxidized
2.5
P/O = ? when FADH2 is oxidized
1.5
