RESPIRATION EXTERNAL RESPIRATION BREATHING PROCESS BY WHICH CELLS

RESPIRATION EXTERNAL RESPIRATION BREATHING - PROCESS BY WHICH CELLS OBTAIN OXYGEN AND RELEASE CARBON DIOXIDE CELLULAR RESPIRATION PROCESS OF RELEASING ENERGY FROM FOOD TO BE USED BY THE CELL

RESPIRATION NET REACTION C 6 H 12 O 6 + 6 O 2 6 CO 2 + 6 H 2 O + ENERGY ACTUAL REACTION C 6 H 12 O 6 + 6 O 2 + 6 H 2 O 6 CO 2 + 12 H 2 O + ENERGY

GLYCOLYSIS • GLUCOSE ENTERS CYTOPLASM (6 CARBON) • ENERGY OF 2 ATP’S USED TO PHOSPHORYLATE (6 CARBON) • TWO 3 CARBON PGAL + P MOLECULES ARE FORMED • TWO HYDROGEN IONS ARE REMOVED FROM EACH AND ACCEPTED BY NAD TO FORM NADH 2 (USED LATER IN AEROBIC RESPIRATION) • TWO ATP ARE GENERATED FOR EACH PGAL MAKING A TOTAL OF 4 ATP • TWO PYRUVIC ACID MOLECULES REMAIN (TO BE USED IN ANAEROBIC OR AEROBIC RESPIRATION) • NET GAIN IS 2 ATP (4 ARE PRODUCED BUT 2 ARE USED)

GLYCOLYSIS ATP ADP + P NAD + 2 H NADH 2 GLUCOSE PGAL +P 2 ADP + 2 P ATP ADP + P NAD + 2 H NADH 2 2 ADP + 2 P 2 ATP PYRUVIC ACID

FERMENTATION BREAKDOWN OF PYRUVIC ACID (ANAEROBIC PROCESS) – DOES NOT PRODUCE ANY ATP – USES NADH 2 AND REGENERATES NAD+ TO BE USED AGAIN IN GLYCOLYSIS • LACTIC ACID FERMENTATION – OCCURS IN SOME UNICELLULAR ORGANISMS AND SOME ANIMAL CELLS (MUSCLE CELLS) – HYDROGEN IONS ARE ADDED TO PYRUVIC ACID FROM NADH 2 IN THE ABSENCE OF OXYGEN – CAUSES MUSCLE SORENESS – TRANSPORTED TO THE LIVER WHERE IT IS CONVERTED BACK INTO PYRUVIC ACID WHEN OXYGEN BECOMES AVAILABLE • ALCOHOLIC FERMENTATION – OCCURS IN SOME UNICELLULAR AND PLANT CELLS (YEAST) – CONVERTS PYRUVIC ACID INTO ETHYL ALCOHOL – NADH 2 DONATES HYDROGEN IONS, CO 2 AND NAD ARE RELEASED – IMPORTANT IN THE BEER AND WINE INDUSTRY – MOST OF THE ENERGY OF THE GLUCOSE REMAINS IN THE PRODUCTS

ANAEROBIC RESPIRATIONFERMENTATION LACTIC ACID FERMENTATION NADH 2 PYRUVIC ACID NAD (Return to Glycolysis) LACIC ACID fermentatio n LACTIC ACID ALCOHOLIC FERMENTATION CO 2 PYRUVIC ACID ALCOHOLI C fermentatio n NADH 2 ETHYL ALCOHOL NAD (Return to Glycolysis)

AEROBIC RESPIRATION • REQUIRES OXYGEN • IS ALWAYS PRECEDED BY GLYCOLYSIS • BREAKS DOWN PYRUVIC ACID INTO CO 2 AND H 2 O • OCCURS IN THE MITOCHONDRIA • BROKEN INTO THREE STEPS – FIRST » PYRUVIC ACID BROKEN INTO CO 2 AND ACETIC ACID AND HYDROGEN IS ADDED TO NAD TO FORM NADH 2 » ACETIC ACID COMBINES WITH CO-ENZYME A TO FORM ACETYL CO-A – SECOND » KREBS CITRIC ACID CYCLE – THIRD » ELECTRON TRANSPORT CHAIN

KREBS (CITRIC ACID) CYCLE • ACETYL CO-A (2 CARBON) ENTERS THE CYCLE AND COMBINES WITH A 4 CARBON (OXALOACETIC ACID) – COENZYME A IS REGENERATED • FORMS A 6 CARBON CITRIC ACID • TWO HYDROGEN AND CO 2 ARE GIVEN OFF (HYDROGEN IS CAPTURED BY NAD TO FORM NADH 2 • FORMS A 5 CARBON (KETOGLUTARIC ACID) • TWO MORE HYDROGEN AND ANOTHER CO 2 ARE GIVEN OFF TO FORM ANOTHER NADH 2 • AN ATP IS GENERATED WITH SOME OF THE ENERGY OF THE REACTION • FORMS A 4 CARBON (SUCCINIC ACID) • TWO MORE HYDROGEN IONS ARE REMOVED TO MAKE FADH 2 USING FAD • FORMS ANOTHER 4 CARBON (MALIC ACID) • TWO MORE HYDROGENS ARE REMOVED BY NAD TO FORM NADH 2 • REGENERATING THE 4 CARBON (OXALOACEIC ACID) TO START THE CYCLE AGAIN

KREBS CITRIC ACID CYCLE PYRUVIC ACID NAD TWO PYRUVIC ACID MOLECULES ARE METABOLIZED IN THE KREBS CYCLE NADH 2 CO-A ACETYL CO-A H 2 O CO 2 NADH 2 CITRI C ACID OXALOACETI C ACID CO 2 H 2 O KETOGLUTARI C ACID NAD ATP MALIC ACID ADP + P SUCCINI C ACID FADH 2 FAD H 2 O NADH 2 CO 2 NAD

SUMMARY OF RESPIRATION • GLYCOLYSIS PRODUCED – 4 ATP - 2 ATP = 2 ATP GAINED – 2 NADH 2 • ANAEROBIC RESP (ACETYL CO-A) – 1 NADH 2 PER PYRUVIC ACID = 2 NADH 2 • KREBS CYCLE – 3 NADH 2 PER PYRUVIC ACID = 6 NADH 2 – 1 FADH 2 PER PYRUVIC ACID = 2 FADH 2 – 1 ATP PER PYRUVIC ACID = 2 ATP TOTALS 4 ATP 10 NADH 2 2 FADH 2

ELECTRON TRANSPORT CHAIN • OCCURS IN THE INNER MEMBRANE OF THE MITOCHONDRIA (CRISTAE) • TRANSFERS ENERGY OF H+ IONS TO ATP • 3 ATP MOLECULES ARE GENERATED FOR EACH MOLECULE OF NADH 2 • 2 ATP MOLECULES ARE GENERATED FOR EACH MOLECULE OF FADH 2 NET YIELD OF ATP FROM ALL RESPIRATION 10 NADH 2 X 3 2 FADH 2 X 2 TOTAL = 30 ATP = 4 ATP + 4 ATP 38 ATP MOLECULES