oxidative phosphorylation Flashcards
where does oxidative phosphorylation occur?
takes place in the cristae (inner mitochondrial membrane)
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 the matrix
- has a proton channel across the membrane
what is the starting molecule of oxidative phosphorylation?
10 reduced NAD from glycolysis, link reaction & 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
