* Cellular Respiration
respiration (system) \neq cellular respiration

circulatory system delivers glucose and O_2 picks up CO_2

C_6 H_{12} O_6 + 6O_2 \Rightarrow_{\text{cellular respiration}} 6CO_2 + 6H_2 O + \text{ATP}

** Steps:
1. Glycolysis
2. Kreb's cycle (TCA crycle, citric acid cycle)
3. electron transport chain (coupled with oxidative phosphorylation)

** Aerobic Cell Respiration
*** Glycolysis:
Conversion of glucose \rightarrow 2 (3C) molecurles (pyruvate)
2 net ATP produced
Occurs in cytoplasm
Occurs without O_2
NADH (caches 2 electrons) loaded with high energy electrons

*** Kreb's Cycle
Occurs in mitochondrion
O_2 required
2 ATP are produced
Carbon completely oxidized to CO_2
NADH and FADH_2 are loaded with high energy electrons

*** Electron transport chain:
Occurs in mitochondria
O_2 is required
NADH and FADH_2 unload high energy electron cargo
Big ATP payoff (around 25 ATP produced)

** Anaerobic Fermentation
Both aerobic and anaerobic do glycoloysis

** Creatine Phosphate
Another source of ATP production