Oxidative Phosphorylation Flashcards
Where does oxidative phosphorylation take place?
The inner mitochondrial membrane
How many protein pumps are involved in the ETC?
. 3 protein pumps involved
. Complex I, III (cytochrome C reductase), IV (cytochrome C oxidase)
Which enzyme links oxidative phosphorylation to the TCA cycle? How so?
. Succinate dehydrogenase (complex II)
. Catalyses the conversion of succinate to fumarate in the TCA cycle, which yields FADH2
Name two enzymes involved in oxidative phosphorylation.
Succinate dehydrogenase and ATPase
Name the two intermediate small components involved in the ETC.
CoQ and Cytochrome C
What is the role of complex I?
. Accepts electrons from NADH and transfers them to CoQ via Fe-S proteins
. Pumps out 4 protons into intermembrane space
What is the role of complex II? Give another name for complex II
. Accepts electrons from FADH2 and transfers them to CoQ via Fe-S proteins
. Succinate dehydrogenase, link to TCA cycle
What is the role of complex IV? Give another name for complex IV.
. Accepts electrons from cytochrome C (oxidising it) and transfers them to 1/2 O2, which is reduced to water
. Pumps out 8 protons into intermembrane space
. Cytochrome C oxidase
What is the role of complex III? Give another name for complex III.
. Accepts electrons from CoQ and transfers them to cytochrome C (reducing it)
. Pumps 2 protons into intermembrane space
. Cytochrome C reductase
What is the role of complex V? Give another name for this complex.
. Catalyses conversion of ADP+ Pi to ATP
. ATPase
Describe the structure of ATPase and how this relates to its function.
. Consists of F0 and F1 region
. F0 is a coupling factor and channel protein which allows protons from the intermembrane space to pass into the mitochondrial matrix
. As the protons move down their concentration gradient through F0, they cause the C-ring of F0 to rotate
. This causes a conformational change in the beta subunit of F1
. ADP and Pi can then bind to F1, which catalyses the conversion to ATP
Name two types of agent that can affect oxidative phosphorylation.
. ATPase inhibitors e.g. oligomycin
. Uncouplers- neutralise proton gradient, which inhibits synthesis of ATP)