Cell Respiration Breathing inhale air to get oxygen exhale air to release carbon dioxide Cell respiration Cells use oxygen and glucose Produce ATP and carbon dioxide

Cell Respiration Glycolysis ““sugar splitting” ooccurs in cytoplasm of the cell Glucose + 2 ATP + 2 NAD + 2 pyruvic acid + 4 ATP + 2 NADH 6-C 3-C

 Depending on the presence/ absence of oxygen, pyruvic acid can take two routes:  1. Aerobic Respiration  2. Anaerobic Fermentation

Aerobic Respiration  Series of reactions that use oxygen to release energy from food.  Occurs in mitochondrion

Aerobic Respiration 33 stages:  Pyruvic Acid conversion  Kreb’s or Citric Acid cycle  Electron Transport chain

Aerobic Cell Respiration Pyruvic acid conversion 22 Pyruvic acid 2 Acetyl Co-A + 2 CO 2  (3-C) (2-C) + (1-C)

Aerobic Cell Respiration Krebs cycle Products: 2 ATP = $ 8 NADH- to ETC 2 FADH 2 - to ETC 4CO 2 - released 2 Acetyl Co-A enter cycle

Aerobic Cell Respiration

Aerobic Cell Respiration Electron Transport Chain  NADH’s and FADH 2 ’s are “cashed in” for ATP’s  Every NADH produces 3 ATP’s  Every FADH 2 produces 2 ATP’s  Water is released

Anaerobic Respiration  Occurs without oxygen  Examples:  Lactic Acid Fermentation  Alcoholic Fermentation

Anaerobic Respiration Lactic Acid Fermentation  Occurs in muscle cells & bacteria  Glucose 2 lactic acid + 4 ATP  Allows muscles to work w/out O 2  Build up of lactic acid causes cramping and fatigue.

Anaerobic Respiration Alcoholic Fermentation  Occurs in plants & yeast  Glucose 2 ethanol + 2 CO2 + 4 ATP  Uses:  Grain & fruit fermentation forms alcoholic drinks  Yeast used in baking bread

Anaerobic Respiration Fermentation  Energy yield  Input 2 ATP to start  Produces 4 ATP  Net: 2 ATP in anaerobic respiration  Compare to 38 ATP formed in aerobic respiration  Which is more efficient?