Respiration

Glycolysis (cytoplasm) Link reaction (mitochondrial matrix) Krebs cycle (mitochondrial matrix) Oxidative phosphorylation (mitochondrial inner membrane-cristae)

Respiration produces ATP

First stage of anaerobic and aerobic respiration. It is an anaerobic process and occurs in the cytoplasm

• Phosphorylating glucose to phosphate using atp • The production of triose phosphate • Oxidation of triose phosphate to produce pyruvate with a net gain of 2 ATP and reduced NAD

Glucose —> glucose phosphate (by phpsphorylating the glucose) —> 2xtriose phosphate -> 2 x pyruvate (oxidation of triose phosphate to produce pyruvate)

2 x pyruvate Net gain of 2 ATP 2 x NADH

Pyruvate and nadh are actively transported from the cytoplasm into the mitochondrial matric

The pyruvate made in glycolysis is oxidised to acetate. NAD picks up the hydrogen and becomes reduced NAD Acetate the combines with coenzyme A in to produce acetylcoenzyme A

Acetyl-CoA reacts with a 4 carbon molecule, releasing coenzyme A and producing a 6 carbon molecule that enters the Krebs cycle. In a series of Redox reactions, the Krebs cycle generates reduced coenzymes and ATP by substrate-level phosphorylation, and carbon dioxide is lost

The products per cycle are: 3 x reduced NAD I x reduced FAD 1 x ATP 2 x CO2

6 x reduced NAD 2 x reduced FAD 2 x ATP 4 x CO2

10 reduced NAD 2 reduced FAD

This stage involves • electron transfer chain • movement of protons across the inner mitochondrial membranes • catalysed by atp synthase

In the absence of oxygen respiration occurs anaerobically. It occurs in the cytoplasm of the cell only

The pyruvate produced in glycolysis is reduced to form ethanol and carbon dioxide (in plants and microbes) or lactate (in animals) by gaining the hydrogen from reduced NAD. This oxidises NAD so that it can be reused in glycolysis and ensure more ATP is continued to be produced

One reduced NAD can result in a yield of 3 ATP molecules, whereas I reduced FAD can result in a yield of 2 ATP molecules.

Therefore, the total yield of ATP from one glucose molecule in aerobic respiration should be 38 molecul: of ATP. Aerobic respiration is approximately 32% efficient. This is due to some protons leaking across the mitochondrial membrane during oxidative phosphorylation, ATP being used to actively transport pyruvate and NADH into the matrix and because some energy is lost as heat.

Anaerobic respiration is even less efficient, because only 2 ATP molecules and produced from one glucose molecule.

From cytoplasm to mitrochondrial matrix. This is an example of cotransport facilitated by active transport so requires carrier proteins

Reduction of pyruvate

Phosphorylation of glucose using ATP; Oxidation of triose phosphate to pyruvate; • Net gain of ATP; 4 produced, 2 used. • NAD reduced;

Less/no reduced NAD/coenzymes • Oxygen is the final/terminal (electron) acceptor;

Regenerates/produces NAD OR oxidises reduced NAD; • (So) glycolysis continues;

Increases dissociation of oxygen; For aerobic respiration at the tissues/muscles/cells Anaerobic respiration delayed at the tissues/muscles/cells Less lactate at the tissues/muscles/cells;