Chap. 7 : Cellular RespirationChap. 7 : Cellular Respiration -- the making of ATP by breaking -- the making of ATP by breaking

down organic compounds (mostly down organic compounds (mostly glucose)glucose)

I.I. GlycolysisGlycolysis -- glucose splits into 2 pyruvic -- glucose splits into 2 pyruvic

acidsacids -- occurs in the cytoplasm-- occurs in the cytoplasm -- requires 2 ATPs but produces 4 -- requires 2 ATPs but produces 4

so net gain of 2 ATPsso net gain of 2 ATPs -- also produces 2 NADH -- also produces 2 NADH

moleculesmolecules

II. II. Fermentation Fermentation – occurs in the absence of – occurs in the absence of oxygen (anaerobic)oxygen (anaerobic)

1. 1. Lactic Acid FermentationLactic Acid Fermentation -- changing of pyruvic acid from glycolysis into -- changing of pyruvic acid from glycolysis into

lactic acidlactic acid -- does not produce ATP so no energy but -- does not produce ATP so no energy but

produces NAD+ that is used to continue produces NAD+ that is used to continue glycolysisglycolysis

**** We can intentionally use to make things **** We can intentionally use to make things like yogurt and cheeselike yogurt and cheese

**** Lactic acid builds up in muscles causing **** Lactic acid builds up in muscles causing them to cramp,fatigue, and painthem to cramp,fatigue, and pain

2. 2. Alcoholic FermentationAlcoholic Fermentation – converts pyruvic – converts pyruvic acid into ethyl alcohol.acid into ethyl alcohol.

Accomplished by yeast – used to make Accomplished by yeast – used to make beer and wine and if CObeer and wine and if CO22 stays trapped stays trapped then champagne.then champagne.

In bread making the escaping of COIn bread making the escaping of CO22 makes air bubbles, the alcohol evaporates makes air bubbles, the alcohol evaporates while bakingwhile baking

*** Anaerobic respiration only produces *** Anaerobic respiration only produces enough energy for unicellular or small enough energy for unicellular or small multicellular organisms to survive.multicellular organisms to survive.

III. III. Aerobic RespirationAerobic Respiration – occurs when O – occurs when O22 is available for pyruvic acid after glycolysisis available for pyruvic acid after glycolysis

Occurs in cytoplasm in prokaryotes and in Occurs in cytoplasm in prokaryotes and in mitochondria of eukaryotes.mitochondria of eukaryotes.

3 parts :3 parts :

1.changing pyruvic acid into Acetyl 1.changing pyruvic acid into Acetyl CoA with the use of CoA enzyme. Makes CoA with the use of CoA enzyme. Makes 2 NADH2 NADH

2. Krebs Cycle-p.1382. Krebs Cycle-p.138

The end result of Krebs Cycle – 1 glucose The end result of Krebs Cycle – 1 glucose molecule makes :molecule makes :

6 NADH, 2 FADH6 NADH, 2 FADH22, 2 ATP, and 4 CO, 2 ATP, and 4 CO22 (everything (everything doubled because it started with 2 pyruvic acids from doubled because it started with 2 pyruvic acids from glucose so goes through Krebs Cycle twice)glucose so goes through Krebs Cycle twice)

3. Electron Transport Chain (chemiosmosis)-changing 3. Electron Transport Chain (chemiosmosis)-changing ADP into ATP by reducing NADH to NAD+ and FADH2 ADP into ATP by reducing NADH to NAD+ and FADH2 to FADto FAD

IV. IV. Electron Transport ChainElectron Transport Chain *** most important step for making energy (ATP) for *** most important step for making energy (ATP) for

cell.cell. --- occurs in cristae of mitochondria. ATP synthase --- occurs in cristae of mitochondria. ATP synthase

molecules line membrane. Chemiosmosis (changing molecules line membrane. Chemiosmosis (changing ADP into ATP) occurs here by proton concentration ADP into ATP) occurs here by proton concentration differences.differences.

A. A. Overall Energy Output from RespirationOverall Energy Output from Respiration

1 NADH = 3ATP1 NADH = 3ATP 1 FADH1 FADH22 = 2 ATP = 2 ATP Glycolysis = 2 ATP + 2NADHGlycolysis = 2 ATP + 2NADH = 8 ATP total= 8 ATP total making Acetyl CoA = 2 NADHmaking Acetyl CoA = 2 NADH = 6 ATP= 6 ATP Krebs Cycle = 6 NADH, 2 FADHKrebs Cycle = 6 NADH, 2 FADH22, 2ATP, 2ATP = 18 + 4 + 2 = 24= 18 + 4 + 2 = 24 Total ATP from the splitting of one glucose Total ATP from the splitting of one glucose

molecule = 38 ATPmolecule = 38 ATP