All you nned to know on respiration

Aerobic Respiration

-Four stages involved in Respiration            

Before you start the best way i found to refvisie this subject was to buy the CGP book alearn the diagrams and draw them out...

All cells respire and dont confuse respiration to breathing.

From GCSE you should know that respiration occurs in mitochondria - a organelle in the cell.

You should also know : C6H1206 + 602 -> 6C02 + 6H20

1) Glycolysis. "Glucose splitting"

2) Link reaction.

3) Krebs Cycle.

4) Oxidative phosphorylation.

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Outline of Respiration


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Aerobic Respiration


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Glycolysis - 1st stage.

Glycolysis occurs in the cytoplasm of cells outside the mitochondria.

- It does not require is an anaerobic process.

-Glycolysis "Glucose splitting"

-One molecule of glucose( with 6 carbons) converted into 2 lots of the smaller 3 carbon molecule called Pyruvate.

There are two stages in Glycolysis- Phosphorylation and Oxidation

**You should know about oxidation-reduciton (redox) reactions. OiL RiG. In Oxidation electrons are Lost by a element/molecule. In Reduction electrons are gained.They can also be descirbes as Oxidation as the loss of hydrogen, Reduction as the gain of hydrogen.

Glucose 6C ->                       2Triose Phosphate3C ->                                2Pyruvate3C

              Phophorylation                                      Oxidation

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Glycolysis - 1st stage.


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Glycolysis - 1st stage.


Glucose -> 2 triose phosphate

1) Glucose is phospohrylated by adding two ATP molecules which donate their P groups

2) Two ADP and two triose phosphate molecules are formed.


 2 triose phosphate converted to two pyruvate

1) Oxidation - OiL. Oxidation is Lose of Hydrogen

Triose phosphate oxidised losing 2 H+. H+ collect by NAD to form Reduced NAD or NADH.

2) 4 ATP produced

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Stage 2 -Link Reaction

Occurs in the Mitochondria.So there must be a net movement of Pyruvate into the Mitochondria form the cytoplasm.

Link reaction converts PYruvate to Acetyl Coenzyme A (acetyl CoA)

1) First Pyruvate is decarboxylated ( a carbon is removed ) ... actually what happens is a CO2 is removed.

2) NAD is reduced the Pyruvate is oxidised... NADH is formed and so is acetate 

3) acetate reacts with coenzyme A for form Acetyl CoA.                

                                                                                     CoA  \

Pyruvate ->                                      Acetate ->                                               Acetyl CoA

                 I                        I                                             

               C02             reduced NAD

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Link reaction


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Link reaction

- Link reaction occurs once for every pyruvate molecule therefore twice for every glucose molecule.

C02 released as waste.

reduced NAD from glycolysisi and link reaction go inot 4th stage of respiration. (oxidative phosphorylation)

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Anaerobic Respiration

Anaerobic respiration 

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Krebs Cycle

Krebs cycle

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Krebs Cycle


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Krebs Cycle


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Oxidative Phosphorylation


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Iram Ali


Page 7 is all jumbled up but still alright :)



you missed out respiratory substrate, chemiosmosisi., etc, chemioosmotic theory..but got most of it :)

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