Respiration for WJEC

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This is the first step in Aerobic respiration 

This process cantake place with or without oxygen and takes place in the cytoplasm of a cell. Gulcose is then phosphoralated ( phosphorus is added) this makes the glucose more reactive thus making it easier to split.

This process yeilds 

  • 2 molecules of ATP
  • 2 molecules of NADH2
  • 2 molecules of Pyruvate ( this is made up of three carbon atoms)

The Pyruvate is dehydrated

NAD is Nicotinamide Adenine Dinucleotide NADH2 is the reduced version of this molecule, it has had hydrogen added to it.

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The Link Stage

 This must take place where there is oxygen. This stae takes place in the matrix of the Mitochrion.

This process converts Pyruvate into Acetyl co enzyme A. In order to do this the Pyruvate must be decarboxylated ( the removal of CO2) and Co enzyme A must be  added. This molecule can then go on to play a role in the Krebs cycle

This reaction yeilds

  • 2CO2 molecules
  • 2NADH2 molecules

when you look at what the reactions yeild think about how this relates to the equation for respiration

C6H12O6+6O2= 6CO2+6H2O +38 ATP

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Krebs Cycle


This is because there are two molecules of Pyruvate produced for each molecule of glucose

The Acetyl co enzyme A combines with an acid which as four carbons ( to create an acid which has 6 carbons) this molecule is then decarboxylated to form an  acid which has 5 carbons attached to it an then again to produce th 4 carbon acid we started with.

Per molecule of Gulcose this reaction Yields

  • 2 ATP
  • 4CO2
  • 6NADH2
  • 2FADH2

FAD is NAD's friend - it stands for Flavin Adenine Dinucleotide

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