Electron Transport Chain Flashcards
Why is the Electron Transport Chain important?
The electron transport chain (ETC) is the main source of ATP production in the body and as is vital for life.
Where is the electron transport chain located?
The electron transport chain is located in the mitochondria.
Complexes in the ETC
There are five main protein complexes in the ETC, located in the inner membrane of the mitochondria.
These are labelled Complexes I, II, III, IV and V.
How do NADH and FADH2 begin donating their electrons?
The two electron carriers, NADH and FADH2, begin the chain by donating their electrons to Complex I and Complex II respectively.
These electrons are then passed along to the next complex in the chain.
What is the result of NADH and FADH2 donating their electrons?
This process generates energy which is used to pump hydrogen ions into the intermembrane space.
In doing so, a proton motive force is generated.
This is an electrical and chemical gradient of hydrogen ions between the intermembrane space and the matrix.
The main route for protons to re-enter the matrix is via ATP synthase or Complex V.
What does ATP synthase do?
Allows the proton motive force to be discharged and utilised by the cell.
This energy generated by hydrogen ions diffusing back into the matrix via Complex V is harnessed, thereby creating ATP from ADP.
What happens when the concentration of ATP rises?
Less ADP for ATP synthase to use. Therefore, there is a limitation in periods of high respiration to avoid large amounts of ATP from being produced.
What can happen when electrons and hydrogen ions combine?
The electrons, meanwhile, combine with the hydrogen ions and oxygen to form water by Complex IV. However, this process is not perfect.
Electrons can leak out of the electron transport chain and can reduce oxygen, which can produce free radicals such as superoxide and hydrogen peroxide.
What does uncoupling proteins do?
Provide an alternative route for proteins to pass into the matrix through the membrane.
