3. Cellular Respiration Defined: The process (a series of reactions) by which glucose molecules are broken down to release energy Defined: The process (a series of reactions) by which glucose molecules are broken down to release energy Purpose: Convert food (such as glucose) into ATP Purpose: Convert food (such as glucose) into ATP Two Types: Two Types: Aerobic process: reaction requires O 2 Aerobic process: reaction requires O 2 Can produce 36 ATP molecules from each glucose Can produce 36 ATP molecules from each glucose Anaerobic process: reaction takes place without oxygen Anaerobic process: reaction takes place without oxygen Can produce 2 ATP molecules from each glucose Can produce 2 ATP molecules from each glucose Who? All eukaryotic cells Who? All eukaryotic cells

4. Cellular respiration is a series of chemical reactions that convert the energy in food molecules into a usable form of energy called ATP. Cellular respiration is a series of chemical reactions that convert the energy in food molecules into a usable form of energy called ATP. Cellular respiration Cellular respiration Step 1: Glycolysis Step 1: Glycolysis Step 2: The Krebs Cycle Step 2: The Krebs Cycle Step 3: Electron Transport Step 3: Electron Transport Cellular Respiration

5. Step 1: Glycolysis, the first step in cellular respiration, is a process by which glucose is broken down into pyruvate and energy is released. Glycolysis It occurs in the cytoplasm. Cellular Respiration (cont.)

6. Cellular Respiration Glycolysis Produces Glycolysis Produces Glycolysis 2 NADH 2 NADH 2 ATP 2 ATP 2 pyruvate 2 pyruvate Only about 2 percent of the chemical energy of a glucose molecule is released during glycolysis and enters the mitochondria Only about 2 percent of the chemical energy of a glucose molecule is released during glycolysis and enters the mitochondria The rest is released in step 2! The rest is released in step 2!

7. Reactions in the Mitochondria

8. Step 2: Kreb’s Cycle Where? Where? In the mitochondria What happens? What happens? A) Enzymes break apart the glucose fragments (pyruvate) into a substance called acetyl-CoA B) 2 ATP & CO 2 created along with NADH and FADH 2 C) Energy molecules (energy is contained in the electrons of those above names molecules) sent to inner mitochondrion membrane Mitochondrion C C C C C C En- zyme CO 2 ATP Energy molecule ATP

9. Electron transport All the remaining energy is contained in electrons carried by NADH and FADH 2 Electron transport= the process of transferring energy from NADH and FADH 2 to ATP Requires O 2 Can generate 32-36 ATP Step 3: Electron Transport Chain

10. Mitochondrion Step 3: Electron Transport Chain Where? mitochondrion membrane Where? mitochondrion membrane What happens? What happens? A) Mitochondrion takes in oxygen (aerobic) B) Enzymes + Energy molecule + O 2 bonds ADP + P to create…. Up to 34 ATP molecules O2O2 ATP Energy molecule En- zyme PADP ATP ADP O2O2 P P O2O2 O2O2 O2O2 P ATP

11. Review 1) Which molecule is the energy molecule of cells? 2) Which types of organisms perform cellular respiration? 3) Where does glycolysis occur? 4) What is broken down during glycolysis? 5) What is created as a result of glycolysis? 6) Where is aerobic respiration performed? 7) Name the 2 stages of respiration that take place in the mitochondria. 8) Which waste gas is created by the Kreb’s cycle? 9) How many ATP molecules are made during glycolysis? 10) How many ATP molecules are made during Kreb’s cycle? 11) How many ATP molecules are made during Electron transport chain? 12) How many ATP molecules are made in total?

12. Review Answers 1) Which molecule is the energy molecule of cells? ATP 2) Which types of organisms perform cellular respiration? Eukaryotes 3) Where does glycolysis occur? Cell’s cytoplasm 4) What is broken down during glycolysis? Glucose 5) What is created as a result of glycolysis? 2 ATP and 2 pyruvate 6) Where is aerobic respiration performed? Mitochondria 7) Name the 2 stages of respiration that take place in the mitochondria. The Kreb’s Cycle & The Electron Transport Chain 8) Which waste gas is created by the Kreb’s cycle? CO 2 9) How many ATP molecules are made during glycolysis? 2 ATP 10) How many ATP molecules are made during Kreb’s cycle? 2 ATP 11) How many ATP molecules are made during Electron transport chain? Up to 34 ATP 12) How many ATP molecules are made in total? Up to 38 ATP molecules