Cellular Respiration

Cellular Respiration

A biochemical process where cells convert glucose into ATP, the primary energy currency.

Glycolysis

The first stage of cellular respiration occurring in the cytoplasm, breaking down glucose into two pyruvate molecules.

Link Reaction

Converts pyruvate into acetyl CoA, linking glycolysis and the Krebs cycle.

Krebs Cycle

A sequence of reactions that process acetyl CoA to produce NADH, FADH₂, and ATP.

Electron Transport Chain

A series of complexes that transfer electrons from NADH and FADH₂ to form a proton gradient, driving ATP synthesis.

Anaerobic Respiration

A process that enables ATP production without oxygen, producing either lactate or ethanol.

Phosphofructokinase (PFK)

Key regulatory enzyme in glycolysis that controls the rate based on ATP levels.

ATP Synthase

An enzyme that synthesizes ATP during oxidative phosphorylation, using energy from the proton gradient.

Acetyl CoA

A two-carbon compound formed from pyruvate that enters the Krebs cycle.

Oxaloacetate

A four-carbon molecule that combines with acetyl CoA to form citrate in the Krebs cycle.

Citrate

The first intermediate in the Krebs cycle formed from acetyl CoA and oxaloacetate.

NAD+

A coenzyme that acts as an electron carrier, being reduced to NADH during glycolysis and the Krebs cycle.

FADH₂

A coenzyme that carries electrons to the electron transport chain, generated in the Krebs cycle.

Total ATP Yield

~38 ATP produced per glucose molecule during cellular respiration, varying by cell type.

Key Molecules of Cellular Respiration

Includes glucose, ATP, NAD+, NADH, FAD, FADH₂, pyruvate, acetyl CoA, oxaloacetate, and water.

Final Electron Acceptor

Oxygen, which combines with electrons and protons to form water in the electron transport chain.