2. Cellular Respiration Harvesting Chemical Energy ATP

3. Energy needs of life Animals are energy consumers –What do we need energy for? Synthesis – building molecules and compounds in the body Reproduction Active transport – remember from last week? Movement Temperature control – oh yea…homeostasis

4. Where do we get energy? Energy is stored in organic molecules –carbohydrates, fats, proteins – oh yea, we learned about these things three weeks ago! Animals eat these organic molecules – food!!! Food is digested, providing –fuels for energy (ATP) –raw materials for building more molecules –carbohydrates, fats, proteins, nucleic acids

5. ATP What is energy in biology? Whoa! Hot stuff!

6. How do we harvest (get) energy stored in food? Cellular respiration –Process of breaking down food to produce ATP Occurs in mitochondria – remember these from two weeks ago? using oxygen –formula identified below shows glucose, but could be other sugars, fats or proteins glucose + oxygen  carbon + water + energy dioxide C 6 H 12 O 6 6O 2 6CO 2 6H 2 O36ATP  + +++ heat

7. CO 2 + H 2 O + heat Fuel (firewood) O2O2 We “burn fuels” to make energy 1) Combustion – (when you burn firewood, a familiar example) making heat energy by burning fuels in one step ATP CO 2 + H 2 O + ATP (+ heat) 2) Respiration – when you “burn” food making ATP energy (& some heat) by burning fuels in many small steps food (carbohydrates) O2O2

8. How do we use ATP for work in our bodies? A working muscle recycles over 10 million ATPs per second Whoa! Pass me the glucose & oxygen! We can’t store ATP  too unstable  only used in cell that produces it  only short term energy storage  carbohydrates & fats are long term energy storage

9. What do we need to make energy? The “Furnace” –mitochondria Fuel –food carbohydrates, fats, proteins The Helpers –oxygen “aerobic” –enzymes O2O2 food ATP Make ATP! Make ATP! All I do all day… And no one even notices!

10. How do we make ATP from food? ATP ADP + P work 1.The molecule ADP (adenosine diphosphate (“di” means two) joins with another phosphate (P) molecule to form adenosine triphosphate 2.ADP + P  ATP 3.The ATP is then used for cellular work and is broken down again to ADP and P 4.When energy is made available from food, the ADP and P will join together again to produce ATP The cycle repeats, just like a rechargeable battery Follow the numbered steps that correspond with the graphic 1, 4 2 3

11. What if oxygen is missing? Cells are unable to complete aerobic cellular respiration, and anaerobic respiration occurs –Alcohol fermentation can occur Yeast are the organisms that do this –glucose  (breaks down into) ATP + CO 2 + alcohol –beer, wine, bread made this way –Lactic acid fermentation – this is what happens in our muscles! (Ever feel or hear of a “runner’s or swimmer’s burn”? Occurs in bacteria, animals –glucose  (breaks down into) ATP + lactic acid –animals feel muscle fatigue Yogurt made this way O2O2 These only make a little bit of ATP!

12. Resources www.bio.kimunity.com Miller, Ken and Joe Levine. Prentice hall Biology. Pearson Education Inc. New Jersey, 2005.