Protein Respiration

Content copied here from Metabolosomes. To be reformatted once bio process pages are on the wiki.

Aerobic cellular respiration (glucose -> ATP)

The actual process of breaking down glucose for energy takes place in several steps in both prokaryotes and eukaryotes. The only difference is where some of the enzymes are located and organized. Below is a summary of the various reactions with the full names of the molecules and the chemical formulas/abbreviations.

Glycolysis: Glycolysis takes place in several steps, catalyzed by 10 different enzymes with 11 intermediate compounds. The end result is one glucose produces two pyruvate molecules, two ATP molecules and two NADH molecules (which are later converted to 4-5 ATP molecules). Glycolysis occurs in the cytoplasm of both eukaryotes and prokaryotes

The net reaction looks like this:

Glucose + 2 ADP + 2 NAD+ + 2 Pi → 2 pyruvate + 2 ATP + 2 NADH + 2 water

If you'd like to learn more about glycolysis, visit https://www.tuscany-diet.net/2018/02/06/glycolysis/.

Linker reaction:

This reaction connects glycolysis to the next major reaction cycle in ATP production: The Krebs cycle, also known as the citric acid cycle.

2 Pyruvate + 2 CoA + 2 NAD+ + 2 Pi → 2 acetyl-CoA + 2 NADH + 2 CO2

Krebs cycle:

2 acetyl-CoA + 6 NAD+ + 2 FAD + 2 GDP + 2 Pi + 4 H2O → 2 CoA + 6 NADH + 6 FADH2 + 4 H+ + 2 GTP + 4 CO2

Electron transport chain and oxidative phosphorylation:

10 NADH + 10 H+ + 2 FADH2 + 2 GTP + 6 O2 -> 25ATP + 3 ATP + 2 ATP

Remeber there is also 2 ATP produced by glycolysis. This brings the total amount of ATP produced to 32.

However, the actual maximum amount of ATP possible varies between species and tissues due to differences in the amount of hydrogens pumped across the mitochondrial membrane by the electron transport chain. In other words, the amount of ATP generated per NADH and FADH2 molecule depends on the species. The total amount is commonly stated as being between 36-38 ATP.

Abbreviations:

ATP: Adenosin TriPhosphate

ADP: Adenosine DiPhosphate

NAD+: Nicotinamide Adenine Dinucleotide

NADH: Nicotinamide Adenine Dinucleotide (Hydrated)

FAD: Flavin Adenine Dinucleotide

FADH2: Flavin Adenine Dinucleotide (Hydrated)

GTP: Guanosine TriPhosphate

GDP: Guanosine DiPhosphate

Pi: inorganic Phosphate

CoA: Coenzyme A

CO2: Carbon Dioxide