Chapter 9

Respiration

The route from food to energyGlucose

Then

With oxygen

Aerobic Respiration

Without oxygen

Fermentation

Alcoholic

Lactic Acid

Goes through Glycolysis

Not a lot of ATP made

The route from food to energyGlucose

Then

With oxygen

Aerobic Respiration

Without oxygen

Fermentation

Alcoholic

Lactic Acid

Goes through Glycolysis

Not a lot of ATP made

Glycolysis Breaks glucose down into 2 pyruvic acid

molecules Occurs in cytoplasm

Glycolysis 2 ATP invested 4 ATP generated

2 “net” ATP gained

Fast process! But… runs out of NAD+ rather quickly

Process can’t go further

Glucose

Then

With oxygen

Aerobic Respiration

Without oxygen

Fermentation

Alcoholic

Lactic Acid

Goes through Glycolysis

Not a lot of ATP made

Fermentation Occurs after glycolysis Does not require oxygen

Anaerobic

Switches NADH back into NAD+ Allows glycolysis to continue

Fermentation Two flavors

Alcoholic fermentation

Lactic acid fermentation

Alcoholic fermentation Done by yeast and other microbes

Formula

Makes bread, wine, and other food products

Lactic Acid Fermentation Done in our muscles!

And other cells too

Formula

Lactic Acid Fermentation Done in muscles during rapid exercise

Lactic acid causes the pH to drop in your cells Makes you feel a burn, stop until you can get O2

again

Makes cheese, yogurt, buttermilk, sour cream and other products

ALCOHOLIC LACTIC ACID

Glucose

Then

With oxygen

Aerobic Respiration

Without oxygen

Fermentation

Alcoholic

Lactic Acid

Goes through Glycolysis

Not a lot of ATP made

Aerobic Respiration After glycolysis Only in eukaryotes Require oxygen—aerobic

NOT THE SAME AS REGULAR RESPIRATION!

Where does aerobic respiration happen? In the mitochondria!

Mitochondria are organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use

2 Main steps of Aerobic Respiration1. Kreb’s cycle

o Pyruvic acid is broken down into CO2 in a series of energy-extracting reactions

• Also known as the Citric Acid Cycle• 2 ATP are generated

Kreb’s Cycle

2 Main steps of Aerobic Respiration2. Electron Transport Chain

o Uses high energy electrons from the Kreb’s cycle to convert ADP into ATPo 32 ATP are produced

Comparing Aerobic Respiration to glycolysis and Fermentation Glycolysis 2 ATP

Fermentation 0 ATP

Kreb’s Cycle 2 ATP

Electron transport 32 ATP

Anaerobic _________ Aerobic ___________

AEROBIC RESPIRATION is 18 TIMES

MORE EFFICIENT!

Where to go for energy? Instant energy—glycolysis LESS

ATP

Fast energy—fermentation

Slow energy—cellular respiration MOST ATP