Cellular RespirationHarvesting Chemical Energy

ATP

Energy needs of life Animals are energy consumers

What do we need energy for? synthesis reproduction active transport movement temperature control

Where do we get energy? Energy is stored in organic molecules

carbohydrates, fats, proteins Animals eat these organic molecules food

digest food to get fuels for energy (ATP) raw materials for building more molecules

carbohydrates, fats, proteins, nucleic acids

ATP

What is energy in biology?

Whoa! Hot stuff!

Harvesting energy stored in food Cellular respiration

breaking down food to produce ATP in mitochondria using oxygen

formula shows glucose, but that is just an example could be other sugars, fats or proteins

glucose + oxygen carbon + water + energydioxide

C6H12O6 6O26CO2 6H2O ATP+ + + + heat

What do we need to make energy? The “Furnace”

mitochondria

Fuel food

carbohydrates, fats, proteins

The Helpers oxygen

“aerobic” enzymes

O2

food

ATP

Make ATP!Make ATP!

All I do all day…And no one

even notices!

CO2 + H2O + heatfuel

(carbohydrates)

O2

“Burn fuels” to make energycombustionmaking heat energy by burning fuels in one step

ATP

CO2 + H2O + ATP (+ heat)

respirationmaking ATP energy (& some heat) by burning fuels in many small steps

food(carbohydrates)

O2

Using ATP to do work?

A working muscle recycles over 10 million ATPs per second

Whoa! Pass me

the glucose& oxygen!

Can’t store ATP too unstableonly used in cell

that produces itonly short term

energy storage carbohydrates & fats

are long term energy storage

ATP

ADP + P

work

A Body’s Energy Budget

eatfood

synthesis

• resting energy• activity• temperature

control{• growth• reproduction{

storage• glycogen• fat{

ATP

What if oxygen is missing? Can’t complete aerobic respiration

alcohol fermentation yeast

glucose ATP + CO2+ alcohol

make beer, wine, bread

lactic acid fermentation bacteria, animals

glucose ATP + lactic acid make yogurt animals feel muscle fatigue

O2

but only make a little bit of ATP!but only make a little bit of ATP!

9-2 The Krebs Cycle and Electron Transport chain

WHAT HAPPENS DURING THE KREBS CYCLE?

Pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

The Krebs Cycle takes place in the mitochondrial matrix

Most of the chemical energy

gets transferred to electron

carriers NAD+ and FAD+

HOW ARE THE HIGH-ENERGY ELECTRONS USED BY THE ELECTRON TRANSPORT CHAIN?

The electron transport chain uses high-energy electrons from the Krebs Cycle to convert ADP to ATP

This stage takes place in the inner mitochondrial membrane

ATP

Any Questions??