Aerobic Respiration

What is glycolysis?

Splitting up glucose into pyruvate whilst producing ATP & Reduced Electron Carriers

Process of Glycolysis

1) 2 ATP is used to phosphorylated Glucose into G-6-P, this is catalysed by using hexokinase.

2) Phosphoglucose Isomerase is used to rearrange G-6-P to F-6-P.

3) Phosphofructokinase-1 is uses ATP to make F-1.6-BP

4) F-1,6-P is cleaved into 2 × (3C): DHAP & GAP.

5) DHAP is converted into GAP by TP Isomerase

6) GAPDH enzyme oxidised GAP, so e^- and H⁺ are donated to reduce NAD⁺ into NADH.

7) This oxidation drives the phosphorylated of GAP into 1,3-BPG.

8) PGK transfers phosphate from 1-3,BPG to ADP, Producing 3-PG & ATP via Substrate Level Phosphorylation

9) Phosphoglycerate mutase moves phosphate from C-3 to C-2, making 2-PG

10) 2-PG then releases a water molecule to make PEP

11) PEP donates a phosphate group to ADP to make ATP, and this tautomerises ineol PEP into a stable keto form of Pyruvate.

How do cells stop wasting unnecessary ATP on glycolysis

G-6-P inhibits hexokinase via a negative feedback mechanism

How much ATP is produced from glycolysis.

2 ATP

After Glycolysis where is pryuvate transported to

Mitochondrial Matrix

Process of Link reaction/ Pyruvate Oxidation

Pyruvagte is transported to mitochondrial matrix, where a carbon is removed, releasing CO2.

The remaining 2-C fragment is oxidised, with the lost electrons being donated to NAD+, reducing it NADH.

The remaining pyruvate becomes bound to CoA, forming Acetyl CoA, catalysed by the pyruvate dehydrogenase complex.

What is Beta Oxidation?

Respiration of Fatty Acids

ketosis

The body uses fat as an alternative energy source due to limited glucose

Ketogenesis

Triglycerides are broken down into fatty acids for energy, when glucose is in low supply.

Beta-Oxidation

Cells hydrolyse fatty acids into acetyl CoA (ready for the Krebs Cycle)

Process of Beta-Oxidation

Fatty acids are ‘activated’ to fatty acyl-CoA by acyl-CoA synthetase in the cytoplasm. (Using an ATP molecule).

Fatty acyl-CoA combines w/ carnitine (carrier protein) sop that it can be transported in the mitochonrdrial matrix (via carnitine acyltransferases).

Oxidation of fatty acyl-CoA (by Acyl-CoA dehydrogenase), reducing FAD⁺ to FADH_2.

_{Hydration w/ Water to form an alcohol (cataylysed by enoyl-CoA hydratse}

Respiration of Fatty Acids

Process of Citric Acid Cycle / Krebs

1) Acetyl-CoA joins with oxaloacetate to form Citrate

2) Citrate is converted into Isocitrate

3) Isocitrate is then oxidised into alpha-ketoglutarate, using Isocitrate Dehydrogenase

4) Alpha-glutarate is then oxidised into a 4-C molecule, forming Succinyl-CoA, this produces NADH & CO₂.

5) Succinyl-CoA is converted into Succinate, making CO₂ & GTP.

6) Succinate is then converted into Fumarate, and FADH₂ is produced.

7) Fumarate is converted into Malate

8) Malate is converted back into Oxaloacetate, & NADH is produced