Cellular Respiration Definition: Gradual release of energy by the break-down of food molecules in aerobic conditions (= O 2 present) Definition: Gradual release of energy by the break-down of food molecules in aerobic conditions (= O 2 present)

Where does the energy in food come from? Light provides the energy to make molecules from…

+ Water

6CO 2 +H 2 O  C 6 H 12 O 6 +6O 2 Photosynthesis takes place in grasses (and other plants) growing… Which are eaten by cattle

And end up as food on our Plates

How does energy get released from food? In humans and many other vertebrates: Food particles get broken down in the digestive system. Chewing - teeth Acids and Enzymes - stomach Enzymes – small intestine

Role of the small intestine In the small intestine, the broken down food particles diffuse into the capillaries (small blood vessels).*vessels).* Tiny food particles (glucose) are carried in the blood to each cell in the body.

Which organelle releases the energy from glucose?

What happens next? In the mitochondrion, each molecule of glucose is broken down into smaller particles. When this happens ENERGY is released. This ENERGY is stored in molecules of ATP.

Why are mitochondria called the POWERHOUSE OF THE CELL?

Cell Respiration Lab With your group: Read over the entire lab and discuss the pre-lab questions.

Aerobic vs. Anaerobic Aerobic = O 2 present Anaerobic = No O 2 present Can organisms break down glucose and release its energy in anaerobic conditions?

YES! Fermentation – an anaerobic cellular process by which glucose is broken down. Fermentation - used by organisms that need small quantities of energy: unicellular organisms or simple multicellular organisms AND Fermentation – used when energy is needed very quickly by muscle cells in animals.

Fermentation Two types of fermentation a) lactic acid fermentation b) alcohol fermentation.

Lactic Acid Fermentation Used by bacteria for the breakdown of glucose. Used to produce yogurt and cheeses. Used by muscles when energy is needed quickly (a sprint), and O 2 is in short supply. Lactic acid build up causes a burning sensation resulting in “sore muscles”.

Alcoholic Fermentation When yeast is added to bread dough, the CO 2 that’s produced is released and trapped in the dough—causes bread to rise.*causes bread to rise. The alcohol produced in the reaction evaporates when the bread is baked!

Breaking down Glucose Cellular Respiration Aerobic 3 Stages Nets 36 ATP molecules Fermentation Anaerobic Lactic Acid Fermentation OR Alcoholic Fermentation Nets 2 ATP molecules

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