Cellular Respiration Review

1. Cellular Respiration Review

2. 1. Define cellular respiration. A process that releases energy from food, such as the simple sugar glucose, when there is oxygen present. Cellular Respiration 2. Name several organisms that undergo cellular respiration Nearly all living things undergo cellular respiration*. Exceptions include a few microscopic marine animals (Loricifera) and some bacteria.

3. 3. Using chemical formulas, write the balanced equation for cellular respiration. Cellular Respiration 6O2 + C6H12O6 6CO2 + 6H2O + Energy 4. Now write out the equation using words. Oxygen + Glucose yields Carbon dioxide + Water + Energy

4. 5. What organelle in eukaryotes is involved in cellular respiration? Cellular Respiration The mitochondrion 6. What is a common analogy for mitochondria? Mitochondria are sometimes called “cellular power plants” or the “powerhouses” of the cell.

5. 7. Where in eukaryotes are mitochondria found? In all cells. Depending on the organism and the type of cell, the number of mitochondria can range from one to thousands. Cellular Respiration Mitochondria Root tip of a corn plant.

6. 8. What kind of human cells contain the most and least number of mitochondria? Cellular Respiration Cells that require the most energy contain the highest number of mitochondria. The cells of the brain, skeletal muscle, heart muscle, and the eye contain the greatest number (as many as 10,000 per cell) while the skin cells, which do not require much energy, contain only a few hundred. Skeletal Muscle

7. 9. Identify the mitochondria in this micrograph of a human pancreatic cell. Cellular Respiration The pancreas secretes insulin in response to glucose levels in the blood. Mitochondria Nucleus Endoplasmic reticulum Nucleolus Pancreas Pancreas cell

8. Identify the following structures of the mitochondrion. Cellular Respiration 10 11 12 13

9. Identify the following structures of the mitochondrion. Cellular Respiration Outer membrane 11 12 13

10. Identify the following structures of the mitochondrion. Cellular Respiration Outer membrane Inner membrane 12 13

11. Identify the following structures of the mitochondrion. Cellular Respiration Outer membrane Inner membrane Inner membrane space 13

12. Identify the following structures of the mitochondrion. Cellular Respiration Outer membrane Inner membrane Inner membrane space Matrix

13. 14. What are the three main stages of cellular respiration? Cellular Respiration Glycolysis (Converting glucose to pyruvic acid) Two pyruvic acid Glucose The Krebs cycle (Breaking down pyruvic acid into CO2) Three Carbon dioxide Pyruvic acid Electron Transport (Making lots of ATP) ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP

14. 15. Where in the mitochondrion does each stage of cellular respiration occur? Cellular Respiration Glycolysis takes place in the cell’s cytoplasm outside the mitochondrion The Krebs cycle occurs in the matrix The Electron Transport Chain operates in the inner membrane.

15. 16. What happens during glycolysis? Four enzymes are used to break glucose into two molecules of G3P* Cellular Respiration Two ATP are invested to get this done. Glucose Two G3P Five enzymes then convert G3P into pyruvic acid** Four ATP are produced. Two pyruvic acid Two electron carriers pick up electrons during the process A net of two ATP are made. ATP ATP ATP ATP ATP ATP ATP ATP Electron carriers Electron carriers *G3P is Glyceraldehyde-3-phosphate ** Pyruvic acid is known as pyruvate

16. 17. What happens in the Krebs cycle? Pyruvic acid enters the mitochondrial matrix where it will enter the Krebs cycle. Cellular Respiration Matrix Mitochondrion Oxaloacetate Acetyl CoA Pyruvic acid Enzymes Electron carriers

17. 17. What happens in the Krebs cycle? Here pyruvic acid will interact with enzymes and other molecules. Cellular Respiration Matrix Mitochondrion Oxaloacetate Acetyl CoA Enzymes Electron carriers

18. 17. What happens in the Krebs cycle? After a series of chemical reactions, three carbon dioxide molecules are produced. Cellular Respiration Matrix Mitochondrion Enzymes Electron carriers

19. 17. What happens in the Krebs cycle? In addition, a molecule of ATP is generated… Cellular Respiration Matrix Mitochondrion Enzymes ATP Electron carriers

20. 17. What happens in the Krebs cycle? Electron carriers* also pick up excess electrons. Cellular Respiration Matrix Mitochondrion Enzymes ATP Electron carriers * Electron carriers NAD+ and FAD

21. 17. What happens in the Krebs cycle? Electron carriers* also pick up excess electrons. They then travel to the inner membrane. Cellular Respiration Matrix Mitochondrion Enzymes ATP Electron carriers Electron carriers Electron carriers Electron carriers Electron carriers * Electron carriers NAD+ and FAD

22. 18. What do the carriers do with their electrons? The electron carriers drop off their electrons at the inner membrane. Cellular Respiration Matrix Mitochondrion Enzymes Electron carriers Electron carriers Electron carriers Electron carriers Electron carriers * Electron carriers NAD+ and FAD

23. 18. What do the carriers do with their electrons? The carriers then return to the matrix to pick up more electrons while other molecules are recycled. Cellular Respiration Matrix Mitochondrion Enzymes Oxaloacetate Acetyl CoA Electron carriers Electron carriers Electron carriers Electron carriers Electron carriers * Electron carriers NAD+ and FAD

24. 19. What happens to the electrons at the inner membrane? Cellular Respiration At the inner membrane, the electron carriers attach themselves to membrane proteins. Matrix H + ions Inner membrane Inner membrane space ATP Synthase Electron carriers Cytoplasm Outer membrane

25. 19. What happens to the electrons at the inner membrane? Cellular Respiration The electrons are then passed to the protein. Matrix H + ions Inner membrane Inner membrane space ATP Synthase Electron carriers Cytoplasm Outer membrane

26. 19. What happens to the electrons at the inner membrane? Some of the energy from the transfer of electrons is used to pump hydrogen ions (H+) into the inner membrane space. Cellular Respiration Matrix H + ions Inner membrane Inner membrane space ATP Synthase Cytoplasm Outer membrane

27. 19. What happens to the electrons at the inner membrane? Meanwhile, the shuttle protein ubiquinone moves in to pick up the electrons. Cellular Respiration Matrix H + ions Inner membrane Inner membrane space ATP Synthase Ubiquinone Cytoplasm Outer membrane

28. 19. What happens to the electrons at the inner membrane? The shuttle will move the electrons to the next protein. Cellular Respiration Matrix H + ions Inner membrane Inner membrane space ATP Synthase Ubiquinone Cytoplasm Outer membrane

29. 19. What happens to the electrons at the inner membrane? Some of the energy from the transfer of electrons will be used to pump more H+ ions across the membrane. Cellular Respiration Matrix H + ions Inner membrane Inner membrane space ATP Synthase Cytochrome C Cytoplasm Outer membrane

30. 19. What happens to the electrons at the inner membrane? Cellular Respiration The electrons will then be shuttled by cytochrome c to their last protein. Matrix H + ions Inner membrane Inner membrane space ATP Synthase Cytochrome C Cytoplasm Outer membrane

31. 19. What happens to the electrons at the inner membrane? Cellular Respiration Again, H+ ions will be pumped across the membrane. Matrix H + ions Inner membrane Inner membrane space ATP Synthase Cytoplasm Outer membrane

32. 19. What happens to the electrons at the inner membrane? Finally, an oxygen atom will pick up the two electrons along with two H+ ions to form a molecule of water. Cellular Respiration Matrix H + ions Inner membrane Inner membrane space O2 ATP Synthase H2O Cytoplasm Outer membrane

33. 20. Where does the water molecule go? Water will exit the mitochondrion Cellular Respiration Matrix H + ions Inner membrane Inner membrane space ATP Synthase H2O Cytoplasm Outer membrane

34. 21. How will the pH in the inner membrane space change? As more H+ is pumped into the inner membrane space, the space becomes more acidic. This causes the pH to drop. Cellular Respiration Matrix H + ions Inner membrane pH 7.8 Inner membrane space ATP Synthase Cytoplasm pH 7.2 Outer membrane

35. 22. How does the concentration of H+ ions in the matrix compare to that in the inner membrane space? Cellular Respiration There are more H+ ions in the inner membrane space, which sets up a concentration gradient. Matrix H + ions Inner membrane Low H+ Concentration Inner membrane space ATP Synthase Cytoplasm High H+ Concentration Outer membrane

36. 23. In which direction is the concentration gradient? The H+ ions will flow down their concentration gradient from the inner membrane space toward the matrix. Cellular Respiration Matrix H + ions Inner membrane Low H+ Concentration Inner membrane space ATP Synthase Gradient Cytoplasm High H+ Concentration Outer membrane

37. 24. Through what membrane protein will the H+ ions flow? The H+ ions will flow through an enzyme called ATP synthase. This flow provides the energy needed to generate ATP from ADP. Cellular Respiration Matrix H + ions Inner membrane ATP Synthase P ADP ATP Cytoplasm Outer membrane

38. 25. About how many ATP can be generated by cellular respiration from one glucose molecule? One glucose molecule yields about 36 to 38 ATP (2 ATP from glycolysis, 2 ATP from the Krebs cycle, and 32 to 34 ATP from the electron transport chain). Cellular Respiration Matrix H + ions ATP Inner membrane Inner membrane space ATP Synthase ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP ATP Cytoplasm Outer membrane