Cellular Respiration

Definitions

• Recall that 6CO2 + 6H2O -> C6H12O6 + 6O2

enzymes, light , chlorophyll

Cellular Respiration

• Process where mitochondria break food molecules to = ATP

• Three stages–Glycolysis–Krebs Cycle–Electron Transport Chain

Glycolysis• Series of chemical reactions

in cytoplasm that break down glucose

• Glucose 6 carbon = 2 pyruvic acid

• Three carbon compound• 2 ATP to start and only 4 are

produced = 2 net ATP for every glucose

• Forms NADH• Anaerobic • Other two stages are aerobic• Pyruvic acid loses its CO2

• Becomes Acetyl CoA• Also forms NADH + H+

Glycolysis

Krebs Cycle• Similar to Calvin Cycle• Calvin cycle forms glucose,

citric acid cycle breaks down glucose

• Occurs in matrix of mitochondria

• Results in NADH and FADH2

• One ATP per turn, 2 turns per glucose

Electron Transport Chain• Occurs in cristae of mitochondria• Series of carriers accepts

electrons from glucose • NADH and FADH2 pass along the

chain slowly releasing energy• Some hydrogen ions used to

make ATP, others to make electrochemical gradient

• Final electron acceptor = oxygen

• Making this aerobic• Makes 32 ATP

ATP Production For Each Glucose

• Glycolysis – Net gain of 2 ATP, 2 NADH, and 2 Pyruvic Acid

• Acetyl-CoA formation – 2 NADH

• Krebs – 2 ATP, 6 NADH, & 2 FADH2

• ETC – 32 ATP from NADH & FADH2

Fermentation

•Sometimes oxygen is scarce

•Still need to produce ATP•Anaerobic •Two major types

–Lactic Acid fermentation–Alcoholic fermentation

Lactic Acid Fermentation

• Does not go through the electron transport chain

• 2 pyruvic acids + NADH = 2 lactic acid

• 2 ATP per glucose• Quick burst of energy but

goes into oxygen debt and muscle fatigue

Alcoholic Fermentation

• Yeast produces CO2 and ethyl alcohol

• Also produces two ATP• CO2 forms bubbles

• In bread, that’s why there are air pockets

Recall Overall Equation

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

–Exergonic reaction