oxidative phosphorylation Flashcards
where does oxidative phosphorylation occur?
in the cristae
why does oxidative phosphorylation take place in the cristae
provides increased surface area for electron carriers and ATP synthase
where are the electron carriers located?
embedded in cristae, forms a chain
what is the role of ATP synthase
- adds phosphates
- large & stick out into matrix
- has a proton channel across membrane
what is the starting molecule of oxidative phosphorylation
10 reduced NAD from glycolysis, link reaction and Krebs cycle
what is the first stage of oxidative phosphorylation from reduced NAD?
- H ions are delivered to the electron transport chain and co enzymes become oxidised to NAD and FAD
- electrons are accepted by the first electron transport chain
what is the second stage of oxidative phosphorylation
- each protein complex in the cristae (cytochrome) has a ham group containing an iron ion
- this ion accepts electrons and becomes reduced
- it then donates the electrons to the next cytochrome and becomes oxidised
- when electrons are donated, energy is released
what is the third stage of oxidative phosphorylation
- FAD/NAD return to matrix to pick up more H ions and become reused
- 2 reduced FAD come from Krebs
what is the fourth stage of oxidative phosphorylation
energy is used to move H ions from matrix across the inner mitochondrial membrane into the inter membrane space
what is the fifth stage of oxidative phosphorylation
- the lipid composition of the inner membrane differs from the outer membrane so the lipid bilayer is less permeable to small H ions
- due to reduced permeability, H ions accumulate to form a gradient
what is the sixth stage of oxidative phosphorylation
- H ions diffuse through the channels and cause conformational change in ATP synthase
- this catalyses the conversion of ADP and Pi to ATP
