Week 14: (A) Oxidative Phosphorylation Flashcards
What is oxidative phosphorylation?
- High energy electrons (carried by NADH and FADH2) are used to reduce O2 to H2O
- phosphorylation of ADP–> ATP
What is the source of high energy electrons?
NADH & FADH2
What is O2 reduced to?
H2O
What is the high energy electrons from NAD & FADH2 used for?
Their energy is used to pump protons (H+) from the mitochondrial matrix to the intermembrane space
How do these H+ flow back into mitochondrial matrix?
Protons flow back across the membrane, following their concentration gradient
-As a potential energy is made
What is a positive redox potential?
more positive the redox potential, the more readily a molecule is reduced.
What changes in the redox potential when co-factors move down the electron transport chain?
Electrons flow down the electron transport chain. NADH & FADH2 will go from negative to more positive redox potential
what do big jumps in redox potential cause?
equate to big changes in ΔG, meaningful work for the cell
Where does oxidative phosphorylation occur?
inner membrane of the mitochondria
What do the many invaginations in the mitochondrial membrane allow?
increase surface area
allow high conc of enzymes that perform in these e- transport reactions to be concentrated in a space
Are proton pumps close to one another?
YES dues to structure of the membrane
What is the coupling of respiration to ATP synthesis called?
oxidatie phosphorylation
What are the two stages in oxidative phosphorylation?
electron transport & ATP synthesis
What are 3 stages in electron transport?
- Electrons flow from NADH and FADH2 to O2
- Respiratory chain
- Energy is used to pump H+ out of the mitochondrial matrix
What are the 2 stages in ATP synthesis?
- Electrochemical gradient of H+ across mitochondrial inner membrane (osmotic charge)
- Energy stored in this gradient can be used to synthesise ATP
Is electron transport and ATP synthesis catalysed by separate proton pumps?
YES
Where do the e- from?
NADH & FADH2
What pumps, pump e- across the inner mitiochondrial membrane?
complex i, iii & iv
What does the increased positive change in the intermediate space cause?
positive charge
electrostatic attractions & conc gradient
What channel is used for H+ to flow through back into the matrix?
ATP synthase
What does ubiquinone do?
coenzyme Q, rapidly shuttles within membrane
How many of the four respiratory complexes pump H+?
3
How does the chain of pumps create an electron gradient?
Transfer of electrons through the respiratory chain
What membrane are the pumps located?
inner mitochondrial membrane
