Cellular Respiration

Steps

Throughout glycolysis, pyruvate oxidation and Krebs cycle, glucose is oxidized and electron carriers ( ${NAD}^{+}$ and $FAD$ ) are reduced. They then transport the electrons to the ETC.

Glycolysis

Glucose -> 2 Pyruvate + 2 $NADH$ + 2 ATP
Substrate-level phosphorylation

In cytosol

Phases:

Energy investment phase: glucose + 2 ATP -> 2 G3P
Energy payoff phase: 2 G3P -> 2 Pyruvate + 2 $NADH$ + 4 ATP

Pyruvate oxidation

2 Pyruvate -> 2 Acetyl-CoA + 2 $NADH$ + 2 ${CO}_{2}$

In mitochondria

Krebs cycle

2 Acetyl-CoA -> 6 $NADH$ + 2 ${FADH}_{2}$ + 2 ATP + 4 ${CO}_{2}$
Substrate-level phosphorylation
A.k.a. citric acid cycle

In mitochondria

Electron transport & chemiosmosis

10 $NADH$ + 2 ${FADH}_{2}$ + 6 $O_{2}$ -> 6 $H_{2} O$ + 26-28 ATP
Oxidative phosphorylation

In mitochondria
Makes most of the ATP

Steps:

Complex I / II transfers electrons from $NADH$ / ${FADH}_{2}$ to ETC.
Electrons flow through ETC and gives energy to complexes I, III and IV to pump protons to the intermembrane space to generate a proton gradient.
Protons flow through ATP synthase into the matrix, powering phosphorylation.

Contributors

Ajitani Hifumi

Changelog

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Cellular Respiration ​

Steps ​

Glycolysis ​

Pyruvate oxidation ​

Krebs cycle ​

Electron transport & chemiosmosis ​