CELLULAR RESPIRATION

WHO DOES CELLULAR RESPIRATION? Animals Humans Plants/Algae Basically any organism with nuclei & mitochondria So what other organisms have mitochondria? Mitochondria: organelle in cell that functions in production of energy

WHAT IS CELLULAR RESPIRATION? 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O + 36ATP Exothermic reaction Occurs in the mitochondria Enzymes are necessary for reaction to occur Where have you heard enzymes before?

WHY DO THEY DO IT? To release energy stored in food To convert the energy into a different form of energy that the organism’s cell(s) can use

2 TYPES OF RESPIRATION Aerobic: oxygen is present; large amounts of ATP are produced Anaerobic: absence of oxygen; less amounts of ATP are produced

AEROBIC RESPIRATION: 3 STEPS Glycolysis: the breakdown of glucose (C 6 H 12 O 6 ) into pyruvate (3 carbon compound); 2 ATPs formed Kreb’s Cycle (Citric Acid Cycle): converts pyruvate into CO 2 ; 2 ATPs formed Electron Transport Chain: uses NADH & FADH 2 (just carrier molecules) to form 32 ATPs & water

CELLULAR RESPIRATION

GLYCOLYSIS Means “splitting of sugar” Breakdown of glucose into pyruvate Occurs in cytoplasm of cell Since it happens in the cytoplasm, what does this mean? Produces 2 ATP molecules

KREB’S CYCLE Converts pyruvate into CO 2 Occurs in the mitochondria Produces 2 ATP molecules + NADH + FADH 2 + CO 2 Remember NADH and FADH 2 are just carrier molecules.

ELECTRON TRANSPORT CHAIN Uses NADH & FADH 2 to form ATP & H 2 O Occurs in mitochondrial membrane Produces 32 ATP molecules & water END RESULT: 36 ATP molecules

ANAEROBIC CELLULAR RESPIRATION 2 types: Alcohol Fermentation Lactic Acid Fermentation Fermentation: the anaerobic (no oxygen) conversion of sugar to carbon dioxide

ALCOHOL FERMENTATION 2 Step Process: Glycolysis [produces 2 ATP molecules] Pyruvate + NADH  Ethanol (alcohol) + NAD + + CO 2 [produces NO energy] Final energy total: 2 ATP molecules from 1 molecule of glucose

ALCOHOL FERMENTATION CONT. Exhibited by yeast in baking bread Used to make wine or beer

LACTIC ACID FERMENTATION 2 Step Process: Glycolysis [produces 2 ATP molecules] Pyruvate + NADH  Lactic Acid + NAD + [produces NO energy] Final energy total: 2 ATP molecules from 1 molecule of glucose

LACTIC FERMENTATION CONT. Exhibited in the souring of milk Occurs in muscle cells when they run out of oxygen

LACTIC FERMENTATION IN MUSCLES When muscles are exercised & there is not enough O 2 in the cells, the cells must get energy another way- lactic acid fermentation.

The lactic acid, if not released, builds up in the muscles & causes fatigue & soreness.

After time, the lactic acid is removed from the muscles, taken to the liver & recycled back into pyruvate.