Cellular Respiration

Cellular Respiration

The process of converting energy in glucose into usable ATP for cellular work.

Overall equation for aerobic cellular respiration

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ~32 ATP.

Stages of Aerobic Respiration

Glycolysis, pyruvate oxidation, citric acid cycle, and oxidative phosphorylation.

Glycolysis location

Occurs in the cytoplasm of the cell.

Outputs of Glycolysis

2 pyruvate, 2 ATP, and 2 NADH.

Pyruvate oxidation

The process in which each pyruvate is converted into Acetyl-CoA and CO₂, producing NADH.

Location of Pyruvate Oxidation

Takes place in the mitochondrial matrix.

Citric Acid Cycle function

To extract high-energy electrons by oxidizing Acetyl-CoA.

Location of Citric Acid Cycle

Occurs in the mitochondrial matrix.

Outputs of Citric Acid Cycle (per glucose)

4 CO₂, 2 ATP, 6 NADH, and 2 FADH₂.

Oxidative Phosphorylation

The production of ATP using energy from electrons transferred through the electron transport chain (ETC).

Location of Oxidative Phosphorylation

Occurs in the inner membrane of the mitochondria (cristae).

Components of Oxidative Phosphorylation

The electron transport chain (ETC) and chemiosmosis.

Electron Transport Chain (ETC)

A series of protein complexes that transfer electrons and pump protons to create a gradient.

Chemiosmosis

The use of a proton gradient to drive ATP synthesis via ATP synthase.

Final Electron Acceptor in ETC

Oxygen, which forms water after accepting electrons.

Total ATP from one glucose molecule (aerobically)

Approximately 30–32 ATP.

Role of NADH and FADH₂ in respiration

They carry high-energy electrons to the electron transport chain.

If oxygen is not available

The cell performs anaerobic respiration or fermentation.

Importance of Cellular Respiration

It provides ATP, which powers nearly all cellular processes.