Cellular Respiration I pp. 131-135

How do organisms “eat”? Autotrophs get energy by making their organic molecules such as glucose through photosynthesis Heterotrophs break down the glucose to make ATP to fuel their metabolism

What is Cellular Respiration? A process that converts glucose into energy Occurs in or near the mitochondria 6 O2 + C6H12O6  6 CO2 + 6 H2O + energy

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Two Pathways Path is determined by the presence of oxygen If O2 is ABSENT then anaerobic respiration occurs in the cytoplasm. If O2 is PRESENT then aerobic respiration occurs in the mitochondrion.

aerobic anaerobic (with oxygen) (without oxygen)

Anaerobic Respiration (no O2) First step is glycolysis Occurs in the cytoplasm by the mitochondria Products: 2 ATP and 2 NADH A (6 carbon) glucose breaks apart in 2 (3 carbon) pyruvic acids Pyruvic acid is also called pyruvate

Anaerobic Respiration (no O2) Second step is fermentation The pyruvate is converted into ethyl alcohol or lactic acid Ex: Wine, Antibiotics, Yeast

Fermentation Alcoholic Fermentation: Occurs in yeast to make wine or champagne Glucose  Pyruvate  Ethyl alcohol and Carbon Dioxide

Fermentation Glucose  Pyruvate  Lactic acid Lactic Acid Fermentation: Can in your muscles during exercise Glucose  Pyruvate  Lactic acid