Oxidative Phosphorylation Flashcards
(32 cards)
Where does oxidative phosphorylation occur in the cell?
On the inner mitochondrial membrane
What determines the number of mitochondria in a tissue?
The energy requirements of that tissue
Which muscle type has more mitochondria and why?
Red muscle as it supports sustained energy output via aerobic respiration and contains myoglobin
Why is the inner mitochondrial membrane crucial for oxidative phosphorylation?
It is impermeable to most polar and ionic substances forcing selective transport and enabling proton gradient formation
What is the consistency and content of the mitochondrial matrix?
- Gel like
- High protein content
- Enzymes for pyruvate dehydrogenase, citric acid cycle and beta oxidation
What is the chemiosmotic theory?
A proton gradient across the inner membrane stores energy used to synthesise ATP
What two components make up the energy in a proton gradient?
- Chemical
- Electrical
How do protons return to the mitochondrial matrix?
Through ATP synthase driving ATP synthesis
Besides ATP synthesis, what other processes are driven by proton gradients?
- Active transport
- Flagellar rotation
- Heat production
- Electrical potential
What tissue uses proton gradients to generate heat instead of ATP?
Brown adipose tissue in neonates and hibernating animals
What is the function of multilocular adipocytes?
They contain many mitochondria and dissipate electron transport energy as heat
What drives electron movement in the electron transport chain?
- A negative change in gibbs free energy
- Electrons move to molecules with higher affinity
What is the difference between acid bace and redox pairs?
- Acid base pairs involve proton transfer
- Redox pairs involve electron transfer
What is redox potential?
A voltage difference relative to a standard that indicates a molecule’s tendency to gain electrons
What are two key mobile electron carriers in the electron transport chain?
- Cytochrome C
- Ubiquinone
What role does ATP synthase play in oxidative phosphorylation?
It converts proton motive force into mechanical rotation that drives the phosphorylation of ADP to ATP
What type of energy conversion occurs in oxidative phosphorylation?
Conversion of redox energy from electron electron flow into a proton gradient then into chemical energy in ATP
What is the overall purpose of oxidativephosphorylation?
To generate ATP using the energy from electrons transferred through the electron transport chain,
What are the two shuttles that transfer electrons from cytosolic NADH into mitochondria?
The glycerol phosphate shuttle and the malate/aspartate shuttle
What does the glycerol phosphate shuttle do?
Transfers electrons from cytosolic NADH to FADH2 in the mitochondrial membrane
What does the malate/aspartate shuttle do?
Transfers electrons from cytosolic NADH to mitochondrial NAD+
What is complex II of the electron transport chain also known as?
Succinate dehydrogenase complex
What are two additional electron donors to the ETC besides NADH?
- Acyl-coA dehydrogenase
- Electron transfer flavoprotein
What determines the rate of oxidative phosphorylation?
The demand for ATP regulated by ADP levels and oxygen availability
