RESPIRATIONEXTERNAL RESPIRATION

BREATHING - PROCESS BY WHICHCELLS OBTAIN OXYGEN AND RELEASE

CARBON DIOXIDE

CELLULAR RESPIRATIONPROCESS OF RELEASING ENERGY

FROM FOODTO BE USED BY THE CELL

RESPIRATION

C6H12O6 + 6 O2 + 6 H2O 6 CO2 + 12 H2O + ENERGY

C6H12O6 + 6 O2 6 CO2 + 6 H2O + ENERGY

NET REACTION

ACTUAL REACTION

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 NADH2 (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

GLUCOSE

PGAL+ P

PGAL+ P

PGAL + P

PGAL + P

PYRUVICACID

PYRUVICACID

NAD + 2HNAD + 2H

NADH2NADH2

ATP

ADP + P

ATP

ADP + P

2 ADP + 2P

2 ATP

2 ADP + 2P

2 ATP

FERMENTATIONBREAKDOWN OF PYRUVIC ACID (ANAEROBIC

PROCESS)– DOES NOT PRODUCE ANY ATP– USES NADH2 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 NADH2

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– NADH2 DONATES HYDROGEN IONS, CO2 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

PYRUVICACID

PYRUVICACID

LACIC ACIDfermentatio

n

NADH2 NAD (Return to Glycolysis)

LACTICACID

ALCOHOLIC

fermentation

CO2

ETHYLALCOHOL

NADH2 NAD (Return to Glycolysis)

ALCOHOLIC FERMENTATION

AEROBIC RESPIRATION• REQUIRES OXYGEN• IS ALWAYS PRECEDED BY GLYCOLYSIS• BREAKS DOWN PYRUVIC ACID INTO CO2

AND H2O• OCCURS IN THE MITOCHONDRIA• BROKEN INTO THREE STEPS

– FIRST» PYRUVIC ACID BROKEN INTO CO2 AND ACETIC

ACID AND HYDROGEN IS ADDED TO NAD TO FORM NADH2

» 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 CO2 ARE GIVEN OFF (HYDROGEN IS

CAPTURED BY NAD TO FORM NADH2

• FORMS A 5 CARBON (KETOGLUTARIC ACID)• TWO MORE HYDROGEN AND ANOTHER CO2 ARE GIVEN

OFF TO FORM ANOTHER NADH2

• 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

FADH2 USING FAD• FORMS ANOTHER 4 CARBON (MALIC ACID) • TWO MORE HYDROGENS ARE REMOVED BY NAD TO FORM

NADH2

• REGENERATING THE 4 CARBON (OXALOACEIC ACID) TO START THE CYCLE AGAIN

KREBS CITRIC ACID CYCLE

PYRUVICACID

CO2

CO-A

CITRIC

ACIDOXALOACETI

CACID

NAD NADH2

ACETYLCO-A

CO2

NAD NADH2

SUCCINIC

ACID

KETOGLUTARIC

ACID

CO2

NADNADH2

MALICACID

ATP ADP + P

FADFADH2

NAD

NADH2

H2 O

H2 O

H2 O

TWO PYRUVIC ACIDMOLECULES ARE

METABOLIZED IN THEKREBS CYCLE

SUMMARY OF RESPIRATION• GLYCOLYSIS PRODUCED

– 4 ATP - 2 ATP = 2 ATP GAINED– 2 NADH2

• ANAEROBIC RESP (ACETYL CO-A)– 1 NADH2 PER PYRUVIC ACID = 2 NADH2

• KREBS CYCLE– 3 NADH2 PER PYRUVIC ACID = 6 NADH2

– 1 FADH2 PER PYRUVIC ACID = 2 FADH2

– 1 ATP PER PYRUVIC ACID = 2 ATP

TOTALS

4 ATP

10 NADH2

2 FADH2

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 NADH2

• 2 ATP MOLECULES ARE GENERATED FOR EACH MOLECULE OF FADH2

NET YIELD OF ATP FROM ALL RESPIRATION

10 NADH2 X 3 = 30 ATP 2 FADH2 X 2 = 4 ATP

+ 4 ATPTOTAL 38 ATP MOLECULES