Exam 4 (Topic 20) Flashcards
Increases membrane surface
Cristae
The inner membrane of mitochondria form extensive folds
Where is the electron transport chain?
Folds of the inner membrane (cristae)
Two main stages of the ETC
- Oxidation of electron carriers and pumping of protons (down the gradient) across the membrane from the matrix to the intermembrane space
- Creation of ATP
Stage 1 and Stage 2 are two separate events but a ___________ ____________ relationship
Chemiosmotic Coupling
Refers to ATP synthesis
chemi
Refers to the movement of H+ across a membrane
Osmotic
Energy from the passage of electrons through the ETC is used to pump protons across the membrane creating a very large
Proton gradient
Protons flow back down the electrochemical gradient through
ATP synthase
Protein complex that makes ATP from ADP + Pi
ATP synthase
In the electron transport chain, protons are pumped from the ________ to the _________ to form the proton gradient.
Matrix, Intermembrane space
NADH and FADH2 are ___________ in the ETC and converted back to ____ and ______
Oxidized
NAD+ and FAD
The electrons move down the ETC and combine with O2 to make
H2O
_______________________ provides the energy to pump protons from the matrix to the intermembrane space
The passage of electrons down the ETC
Protons are going _________ their electrochemical gradient
against
________________ drives the synthesis of ATP and is called __________________
Resulting proton gradient
Oxidative phosphorylation
ETC is made up of over ____ proteins
40
Three main respiratory enzyme complexes
- NADH dehydrogenase complex
- Cytochrome b-c1 complex
- Cytochrome oxidase complex
- NADH dehydrogenase complex
- Cytochrome b-c1 complex
- Cytochrome oxidase complex
Three main respiratory enzyme complexes
ETC begins when…
hydride ion is removed from NADH
NADH becomes oxidized
What energy pumps 1 H+ from the matrix to the intermembrane space?
Two electrons are passed through the NADH dehydrogenase complex and energy is released
Electrons are passed from the NADH dehydrogenase complex to
Ubiquinone
Small lipid soluble molecule that shuttles electrons from NADH dehydrogenase complex to the cytochrome b-c1 complex
Ubiquinone
Electrons are passed from Ubiquinone to the
Cytochrome b-c1 complex
Passage of electrons through the cytochrome b-c1 complex releases energy which is used to
pump 1 H+ from the matrix into the intermembrane space
Electrons are passed from cytochrome b-c1 complex to
cytochrome c
A protein that shuttles electrons from the cyctochrome b-c1 complex to the cytochrome oxidase complex
Cytochrome c
Electrons are passed throught the Cytochrome oxidase complex and again release energy to
pump 1 H+ from the matrix to the intermembrane space
Cytochrome oxidase complex
4 e- + 4 H+ + 1 O2 –> 2 H2O
Path of electrons in ETC
- NADH–> NADH dehyrogenase complex (1 H+ pumped)
- NADH dehydrogenase complex –> Ubiquinon (shuttle)
- Ubiquinone (shuttle) –> Cytochrome b-c1 complex (1 H+ pumped)
- Cytochrome b-c1 complex –> cytochrome c (shuttle)
- Cytochrome c (shuttle) –> cytochrome oxidase complex (1 H+ pumped)
- Cytochrome oxidase complex –> O2 –> H2O
Step 1 of the path of electrons in ETC
NADH–> NADH dehyrogenase complex (1 H+ pumped)
Step 2 of the path of electrons in ETC
NADH dehydrogenase complex –> Ubiquinon (shuttle)
Step 3 of the path of electrons in ETC
Ubiquinone (shuttle) –> Cytochrome b-c1 complex (1 H+ pumped)
Step 4 of the path of electrons in ETC
Cytochrome b-c1 complex –> cytochrome c (shuttle)
Step 5 of the path of electrons in ETC
Cytochrome c (shuttle) –> cytochrome oxidase complex (1 H+ pumped)
Step 6 of the path of electrons in ETC
Cytochrome oxidase complex –> O2 –> H2O
What does not pump H+ from the mitochrondria matrix to the mitochondria intermembrane space?
Cytochrome C
Ubiquinone
Pumping H+ across the inner membrane into the intermembrane space creates two things:
- A large membrane potential
2. A pH gradient
The matrix has an overall negative charge and the intermembrane space has an overall positive charge
Membrane potential
More H+ in the intermembrane space, so pH is lower than in the matrix
pH gradient
Combined, two gradients (membrane potential and pH gradient) add up to a steep
electrochemical gradient
Makes it energetically favorable for H+ to flow back into the matrix
Electrochemical gradient
It is energetically favorable for H+ to flow back into the matrix
Proton Motive Force
Can be used to make ATP
Proton Motive Force
H+ move down the gradient through a protein complex called
ATP synthase
The energetically favorable movement of H+ is used by ______________ to catalyze ADP + Pi –> ATP
ATP synthase
Molecular turbine
ATP Synthase
Two main complexes of ATP Synthase
F0 and F1
The transmembrane portion that allows H+ to flow back through the inner membrane
F0
A “lollipop” head portion that contains ATPase enzymatic activity
F1
The F1 is in the
mitochondria matrix
H+ flow down the electrochemical gradient through a channel in the ____ portion of ATP synthase
F0
Causing the F0 “stalk” to rotate
________ changes the conformation of the F1 portion of ATP synthase which activates the ATPase activity
Rotation
Activates the ATPase activity
When rotation changes the conformation of the F1 portion of ATP synthase
Rotation of the F0 portion can reverse if
Low concentrations of H+ are present
ATP synthase can work
in reverse
Where have seen an ATPase H+ pump?
Lysosome
If ATP synthase is working in reverse it must
Hydrolyze ATP to pump H+
