Target. SWBAT describe both parts of the last step of cellular respiration aerobic respiration.

Transcription

1 Aerobic Respiration

2 Target SWBAT describe both parts of the last step of cellular respiration aerobic respiration.

3 Two Major Stages Krebs Cycle Electron Transport Chain

4 Chart: Page 66 Glycolysis Without O 2 With O 2 Fermentation Aerobic Respiration Kreb s Cycle Electron Transport Chain

5 Where does Aerobic Respiration happen? Takes place in the mitochondria Pyruvic Acid from glycolysis moves from the cytosol into the mitochondria by crossing the mitochondrial membrane

6 Where in the mitochondria? Krebs Cycle: Mitochondrial matrix Electron Transport Chain: Inner membrane

7 Mitochondri a Where ATP is made

8 Why in the Mitochondria? The mitochondria contains enzymes necessary for the Krebs cycle

9 Before the Krebs Cycle can begin As soon as pyruvic acid enters the mitochondria it is converted to Acetyl CoA

10 Pyruvic Acid Conversion: 1 step Pyruvic Acid reacts with Coenzyme A (CoA) to form Acetyl CoA One carbon is removed, forming CO 2 NAD is used during the process and comes out as NADH and H +

11 Next Steps The Acetyl CoA is now ready to move on to the Krebs Cycle

12 Krebs Cycle: Step 1 Acetyl CoA (2C) combines with oxaloacetic acid (4C) Citric Acid is produced (6C) Coenzyme A (CoA) is given off

13 Krebs Cycle: Step 2 NAD comes in and is reduced (gains an electron) to form NADH and H + CO 2 is released A 5-carbon compound results

14 Krebs Cycle: Step 3 NAD comes in and is reduced to NADH and H + CO 2 is released Energy from this step converts 1 ADP to 1 ATP A 4-carbon compound results

15 Krebs Cycle: Step 4 The 4-carbon compound reacts with FAD (flavin adenine dinucleotide) FAD accepts a H+ from the 4- carbon compound and is converted to FADH 2

16 Krebs Cycle: Step 5 NAD comes in and is reduced to NADH and H + The 4-carbon compound is converted to Oxaloacetic Acid The Krebs Cycle begins again

17 Important Point Remember that two Pyruvic Acid molecules are created during glycolysis Therefore the Krebs Cycle can be done twice with one glucose molecule

18 How many ATP are made during the Krebs Cycle? Two ATP One from each Pyruvic Acid made from glucose during glycolysis

19 Questions So far, has aerobic respiration made more ATP than fermentation? Glycolysis? Where then, can you assume most of the ATP is going to be made? Has oxygen been required for aerobic respiration so far? Where then, can you assume oxygen will be needed?

20 The Electron Transport Chain (Aerobic Respiration Part II) Second stage of aerobic respiration Occurs along the inner membrane of the mitochondria

21 Target SWBAT describe both parts of the last step of cellular respiration aerobic respiration.

22 What happens during the ETC? ATP is produced NADH and FADH 2 are regenerated back into NAD and FAD

23 How is ATP produced? To understand this we must follow the electrons and protons that are part of the electron transport chain (ETC)

24 NADH and FADH 2 Both are at a very high energy level when they exit the Krebs Cycle They are at the top of the stairs NADH and FADH 2 are passed through the ETC

25 What happens? The NADH and FADH 2 give off energy during the ETC that is used to pump protons (H+) from the Krebs Cycle across the inner membrane

26 Why pump the protons across the membrane? Protons build up on one side of the membrane to create a high concentration.

27 Equilibrium Do cells like to have a lot of protons on one side of the membrane? No! They want everything even

28 What do the cells do? Protons will begin to move across the inner membrane to an area of low concentration When they do this the energy is used to convert ADP into ATP. (Remember the light reactions?)

29 What next? What happens if protons just keep flowing down the ETC forever? Think about cars driving down a one way road to a dead end

30 Clearing the backup This is where oxygen comes in Oxygen accepts electrons and protons at the end of the ETC This helps remove protons so that the ETC can continue

31 Look Familiar? O 2 + 4e- + 4H + 2H 2 O Think about the ETC that occurs during the light reactions!

32 How many ATP? How many ATP are made by the ETC? 1 glucose molecule 34 ATP

33 How many ATP are made total? Glycolysis Krebs Cycle 2 ATP 2 ATP Electron Transport Chain +34 ATP Total 38 ATP

34 Cellular Respiration Equation C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + Energy

35 What does it look like? Cellular Respiration looks a lot like Photosynthesis

36 Important Point Cellular Respiration is not the opposite of Photosynthesis They occur in different organelles They serve different purposes Cellular Respiration is not ONLY for making ATP

37 What else is Cellular Respiration for? In addition to ATP, Cellular Respiration provides the building blocks that cells need to make structural compounds for your body like protein, carbohydrates and lipid.