1. 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)

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

3. + Water

4. 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

5. And end up as food on our Plates

6. 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

7. Role of the small intestine Tiny projections called villi line the small intestine (increases surface area), which absorb digested food into the capillaries (small blood vessels).*vessels).*

8. Food, Energy and Blood Tiny food particles (glucose) is carried in the blood to each cell in the body. Glucose enters each cell by the process of _______________________ Facilitated diffusion

9. Which organelle releases the energy from glucose?

10. What happens next? The chemical reaction for cellular respiration: High energy bonds low energy bonds 6O 2 + C 6 H 12 O 6  6H 2 O + 6CO 2 __________ What is missing from the equation? + ENERGY

11. Cellular respiration Occurs in THREE STAGES This allows the energy found in glucose to be released slowly rather than all at once. The energy in glucose is found in chemical bonds. When the bonds are broken, the energy is released and stored in molecules of ATP for later use!

12. Stage 1 - Glycolysis What happens? 1 molecule of glucose is broken into 2 molecules of pyruvic acid. Higher energy Lower energy C 6 H 12 O 6  2 C 3 H 4 O 3 + 4H + _____________ (glucose) (pyruvic acid) 1 (6) carbon molecule  2 (3) carbon molecules What is missing from the equation? + ENERGY

13. Glycolysis (Cont) Glycolysis releases energy. The energy is stored in the chemical bonds of two molecules. ADP (low energy) is converted to ATP (high energy) and NAD + (nicotinamide adenine dinucleotide) is converted into NADH (holds high energy electrons)

14. Glycolysis (cont) The amount of energy produced from glycolysis is small but the process occurs quickly. Glycolysis nets 2 ATP molecules Glycolysis releases only about 10% of all of the energy stored in the chemical bonds holding the glucose molecule together. Glycolysis occurs in the cytoplasm of cells*cells

15. Stage 2 – Krebs Cycle or Citric Acid Cycle Hans Krebs (1900–1980) Discovered the citric acid cycle, (aka) Krebs Cycle, in 1937. Awarded the Nobel Prize for his discovery in 1953.

16. Krebs Cycle Under aerobic conditions (O 2 present), pyruvic acid, passes to the second stage of cellular respiration What happens? Overall – Pyruvic acid is broken down into CO 2, A small amount of energy is stored in ATP, High energy electrons are stored in NADH

17. Krebs Cycle (cont) Pyruvic acid  3CO 2 + ENERGY NAD + (electron carrier) is converted into NADH (holds high energy electrons) Low energy ADP is converted to high energy ATP The CO 2 that is released in this reaction is the CO 2 that is exhaled in plant and animal respiration*.animal respiration*

18. Krebs Cycle (cont) Occurs in the mitochondrion of Eukaryotes  Occurs in the cytoplasm of Prokaryotes

19. Stage 3 – Electron Transport Chain Electron transport chain – series of reactions What happens? High energy NADH converts low energy ADP into ATP. About 34 ATP molecules are formed from the Krebs cycle and electron transport chain combined. Occurs in the mitochondrion of Eukaryotes Occurs in the cytoplasm of Prokaryotes

20. Why are mitochondria called the POWERHOUSE OF THE CELL?

21. Cell Respiration Together ____________, the _______________and the _________________________________________ make up cell respiration. Glycolysis Electron Transport Chain Krebs Cycle  In most cells, 1 molecule of glucose produces 36 molecules of ATP.  This amounts to 38% of the total energy stored in glucose. The rest of the energy is released as body heat.  Complete worksheet on Cell Respiration!

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

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

24. 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.

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

26. Lactic Acid Fermentation Stage 1 - Glycolysis occurs. Glucose  ____________________ pyruvic acid Stage 2 – Lactic acid fermentation Pyruvic acid broken down into lactic acid + NAD + Lact = milk!

27. Lactic Acid Fermentation The NAD + restarts the glycolysis reaction which produces 2ATP molecules from 2ADP molecules. 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”.

28. Alcoholic Fermentation Stage 1 - Glycolysis occurs. Glucose  pyruvic acid Stage 2 – Alcoholic fermentation – Process occurs in yeast. Pyruvic acid broken into CO 2 + ethanol alcohol. 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!

29. Breaking down Glucose Cellular Respiration Aerobic 3 Stages Glycolysis Krebs Cycle Electron Transport Chain Nets 36 ATP molecules Fermentation Anaerobic Glycolysis followed by Lactic Acid Fermentation OR Alcoholic Fermentation Nets 2 ATP molecules

30. The End + =