crooler
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so i was studying biology (a level caie) and i totally get the other parts of respiration (glycolysis, link reaction, krebs cycle) but i just cant seem to understand the last part-oxidative phosphorylation and the electron transport chain...

can someone pleeasseee help me out by explaining it in detail so i can understand
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Reality Check
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(Original post by crooler)
so i was studying biology (a level caie) and i totally get the other parts of respiration (glycolysis, link reaction, krebs cycle) but i just cant seem to understand the last part-oxidative phosphorylation and the electron transport chain...

can someone pleeasseee help me out by explaining it in detail so i can understand
A book gives you detail... It's better to give you an overview so you can get the general gist of it, and then you can go back to a book and fill in the details.

All those electrons which have been used to reduce NAD/FAD to NADH/FADH2 during glycolysis and the Krebs Cycle were removed for a purpose. These reduced electron carriers pass their electrons on to a series of (enzyme) proteins in the mitochondrial inner membrane - this series of proteins forms a chain called the electron transport chain.

The electrons from NADH/FADH2 are used to reduce the first protein in the chain - the electron carrier is thus re-oxidised and can be used again. The first protein (or complex) then passes the electron on to the next protein in the chain and so on - it is a series of redox reactions. The final protein in the chain transfers the electrons to molecular oxygen to form water - this is why it's called 'aerobic respiration', because oxygen is required.

As well as reducing oxygen to water, the passing of electrons down the chain causes hydrogen ions, H+, to be pumped out of the matrix of the mitochondria into the intermembranal space. When these protons flow back into the matrix through a special enzyme called ATP-ase, ATP is synthesised (technically, it's released). This is the energy-making part of the ETC, and the H+ flow is called the 'chemiosmotic theory'.

To do:

  • Ensure you understand redox fully, including the definition of 'reduction' meaning the addition of hydrogen and 'oxidation' the removal of hydrogen.
  • Look at the different complexes (proteins) of the ETC, and the carriers which shuttle electrons between them. Which proteins use metal ions, and what metal ions are they?
  • Look at the chemiosmotic theory in more detail, and how the ATPase acts as a 'molecular motor'.
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crooler
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(Original post by Reality Check)
A book gives you detail... It's better to give you an overview so you can get the general gist of it, and then you can go back to a book and fill in the details.

All those electrons which have been used to reduce NAD/FAD to NADH/FADH2 during glycolysis and the Krebs Cycle were removed for a purpose. These reduced electron carriers pass their electrons on to a series of (enzyme) proteins in the mitochondrial inner membrane - this series of proteins forms a chain called the electron transport chain.

The electrons from NADH/FADH2 are used to reduce the first protein in the chain - the electron carrier is thus re-oxidised and can be used again. The first protein (or complex) then passes the electron on to the next protein in the chain and so on - it is a series of redox reactions. The final protein in the chain transfers the electrons to molecular oxygen to form water - this is why it's called 'aerobic respiration', because oxygen is required.

As well as reducing oxygen to water, the passing of electrons down the chain causes hydrogen ions, H+, to be pumped out of the matrix of the mitochondria into the intermembranal space. When these protons flow back into the matrix through a special enzyme called ATP-ase, ATP is synthesised (technically, it's released). This is the energy-making part of the ETC, and the H+ flow is called the 'chemiosmotic theory'.

To do:

  • Ensure you understand redox fully, including the definition of 'reduction' meaning the addition of hydrogen and 'oxidation' the removal of hydrogen.
  • Look at the different complexes (proteins) of the ETC, and the carriers which shuttle electrons between them. Which proteins use metal ions, and what metal ions are they?
  • Look at the chemiosmotic theory in more detail, and how the ATPase acts as a 'molecular motor'.
oh..
thank you so muchh!!!!!!! i really appreciate it!!!!
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Reality Check
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(Original post by crooler)
oh..
thank you so muchh!!!!!!! i really appreciate it!!!!
You're welcome. Does that help? Does it make sense? Anything else you need clarification on?
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crooler
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(Original post by Reality Check)
You're welcome. Does that help? Does it make sense? Anything else you need clarification on?
yeahhh it toally does help and it does makes total sense
and no, i think i got it from here

thank you so so much thoo!!!!! this really helped a lot!!!!
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Reality Check
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(Original post by crooler)
yeahhh it toally does help and it does makes total sense
and no, i think i got it from here

thank you so so much thoo!!!!! this really helped a lot!!!!
Great
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