Cellular Respiration …getting the energy back out of glucose

Photosynthesis Solar energy is stored in chemical bonds

Cellular Respiration Energy from chemical bonds extracted and used

Energy stored Photosynthesis Energy extracted Cellular respiration

Energy stored Photosynthesis Energy extracted Cellular respiration

Photosynthesis Cellular respiration animal plant

glucose + 6H20 + 6O2 6CO H20 Energy released and used Cellular respiration

1 / 2 O 2 H2H2 + H2OH2O Explosive release of heat and light energy Free energy, G Uncontrolled

2 H e – 2 H (from food via NADH) Controlled release of energy for synthesis of ATP 2 H + 2 e – H2OH2O + 1 / 2 O 2 Free energy, G Electron transport chain Cellular Respiration

Cellular respiration: 3 parts *Glycolysis *Krebs Cycle *Electron transport chain linking reaction

Cellular respiration

Glycolysis

Glycolysis: the gory details

Gylcolysis: splitting a glucose

Energy Still more potential energy

Linking Reaction

The linking reaction Glycolysis Krebs Cycle Energy Still more potential energy

Krebs Cycle

Krebs Cycle: the gory details

Krebs Cycle Energy

Electron transport Chain

Electron transport chain Electrons fall ‘down hill’ giving up energy

Water falls down hill giving up energy

Electron transport chain Electrons fall ‘down hill’ giving up energy High energy Low energy Energy released

Electron transport chain

Energy from falling electrons runs a pump

Pump creates concentration gradient of hydrogen ions (= protons)

Energy is in form of imbalance of protons (H+) across membrane

Protons (H+) flow through membrane running a ‘water wheel’

Energy from proton flow is captured in ATP recharging

ATP Synthase

Where’s the energy?

The Yield for Cellular Respiration 1 glucose molecule: Glycolysis Krebs Cycle 4 ATP Electron transport chain 32 ATP (+ many NADH & FADH)

The Yield

ETC

Electron transport chain High energy Low energy Energy released Oxygen

Aerobic respiration - final electron acceptor is oxygen Anaerobic respiration - final electron acceptor is molecule other than oxygen

Glycolysis

Anaerobic respiration

Lactic acid fermentation

Alcohol fermentation

Pyruvate Glucose CYTOSOL No O 2 present Fermentation Ethanol or lactate Acetyl CoA MITOCHONDRION O 2 present Cellular respiration Citric acid cycle

Citric acid cycle Oxidative phosphorylation Proteins NH 3 Amino acids Sugars Carbohydrates Glycolysis Glucose Glyceraldehyde-3- P Pyruvate Acetyl CoA Fatty acids Glycerol Fats Other pathways

ATP Citric acid cycle Citrate Isocitrate Oxaloacetate Acetyl CoA H2OH2O CO2CO2 NAD + NADH H2OH2O Malate NAD + NADH + H + Fatty acid

Regulating Aerobic Respiration