Cellular Respiration Questions

CELLULAR RESPIRATION QUESTIONS 1. Write the balanced word and chemical equation for aerobic respiration.  Glucose + oxygen  carbon dioxide + water + energy C 6H12O6 + 6O 2  6CO2 + 6H2O + 36 – 38 ATP 2. What is the purpose of cellular respiration?  Cellular respiration is the process that occurs in the mitochondria of organisms (animals and plants) to break down sugar in the presence of oxygen to release energy in the form of ATP. 3. Why is NADH called an electron shuttle bus?  It is called an electron shuttle bus because it picks up electrons/ becomes reduced when another molecule is oxidized and then transfers the electrons to another molecule. 4. What are the two mechanisms in which ATP is generated? Briefly describe each mechanism.  Glycolysis: The enzymes breakdown 1 molecule of glycolysis into 2 molecules of pryruvate. Some hgh – energy ATP and NADH is synthesized. Citric acid cycle: Acetyl – CoA molecules from pyruvate oxidation enter a metabolic cycle, where the acetyl group is completely oxidized to CO 2. In the process, ATP and the electron carriers NADH and FADH 2 are synthesized. 5. Make a comparison chart to show how much ATP is produced from substrate level phosphorylation versus oxidative phosphorylation (use the equivalent amount of ATP for coenzymes).  Substrate level phosphorylation: 2 from glycolysis, 2 from Kerbs Oxidative phosphorylation: chemiosmosis and 32 from Electron transport chain 6. Define the following terms: a. Aerobic cellular respiration c. Substrate level phosphorylation e. Chemiosmosis b. Anaerobic cellular respiration d. Oxidative phosphorylation f. Carboxylation  A. Aerobic Cellular Respiration is a process that uses oxygen to harvest energy from organic compounds B. Anaerobic cellular respiration is a process that uses a final inorganic oxidizing agent other than oxygen to produce energy C. Substrate level phosphorylation: The formation of ATP from the direct transfer of a phosphate group a substrate to ADP D. Oxidative phosphorylation: A process that forms ATP using energy transferred indirectly from a series of redox reactions. E. Chemiosmosis: process where by the energy converted from the electrochemical gradient and the ATPase is used to synthesize ATP F. Carbonxylation: A chemical reaction that add carbon 7.Identify two instances where carboxylation occurs during cellular respiration.   After Glycolysis, Pyruvate oxidation is the next step in capturing the remaining energy in the form of ATP. No ATP is made during this. This step takes place in the matrix. During the pyruvate oxidation, a carboxyl group is removed from pyruvate, realeasing crabon dioxide. NADH+ is reduced to NADH.  Next step is Kreb cycle. In eukaryotes, the citric acid cycle takes place in the matrix of the mitochondria. It has eight catalyzed reactions and only occurs if oxygen is present. During the cycle, it oxidized two of acety-CoA, and release 2 molecules of ATP and CO2. 6 NADH and 2 FADH are produced 8.What role do the following molecules have in cellular respiration: a.NADH & FADH2 b. Hydrogen ions c. Acetyl-CoA e. oxygen d. electrons  A. NADH and FADH: shuttle eletron from glycolysis and kerbs to the electron transport chain B. Hydrogen ions: used to create concenntration gradient in mitochondria (chemiosmosis) C. Acetyl – CoA: a coenzyme used in Kerb cycle – help deliver acetyl group to Kerbs as acetyl-CoA D. Electrons: move through ETC via redox reactions, allowing H+ to be pumped into the intermembrane space and set up a concentration gradient E. Oxygen: Find electron acceptor in ETC ; 9.a. What is the purpose of glycolysis?  Enzymes breakdown one molecule glucose into 2 pyruvate and synthesize NADH. It released 2 ATP b. What are the products of glycolysis?  2 ATP (net), 2 pyruvates 2 NADH c. What gets oxidized? Reduced?  Glyceraldehyde-3-phosphate Reduced: NAD+ 10.a. What are the products of one turn of Krebs cycle?  2 CO2, 6NADH, 2FADH, 2 ATP b. How many turns of the Krebs cycle are required to metabolize one molecule of glucose?  two turns 11. Draw a diagram of a mitochondria and label its parts.  12.What happens to pyruvic acid before it enters the Krebs cycle?  Before the Krebs cycle begins, pyruvic acid, which has three carbon atoms, is aplit apart and combined with an enzyme known as CoA. The product of this reaction is a two-carbon molecule called acetyl – CoA. 13. What happens to the substance entering the Krebs cycle?  For each acetyl- CoA that enters the citric acid cycle, three NADH and one FADH are produced along with one ATP. 14. During Krebs, what products are formed? How many for one molecule of glucose?   CO2, NADH, FADH2, ATP  12 NADH, 8 CO2, 8 ATP, 4 FADH2 15. How is the electron transport chain organized, and what is its purpose? Draw a labeled sketch that shows all of the protein complexes, energy molecules, electron movement, protons and location.  The electron transport chain consists of four complexes that couple redox reactions, creating an electrochemical gradient that leads to the creaction of ATP in a comlplete system named oxidative phosphorylation. 16. Where is the H+ reservoir located in the mitochondria?  intermembrane space Indicate where each part of cellular respiration occurs.  17. What happens to the electrons as they are passed along the electron chain?  They move from a higher to a lower energy level, releasing energy. 18. Explain how ATP is made by chemiosmosis.  The protons that have been released during the Etc creates an electrochemical gradient that can be used to drive the synthesis of ATP 19. At what point on the ETC do the electrons stop from getting passed on? When they join with oxygen 20. What happens to theses electrons after that point? They become part of H 2O 21. What happens to the NAD+ and FAD after it gives electrons to the ETC? They are recycled 22. What is the significance of the inner membrane and intramembrane space in the mitochondria? Inner membrane is where the ETC takes place Intra/ inermembrane space is where there is a high concentration of H+ allowing creation of ATP via ATP synthase 23. Compare alcoholic fermentation and lactic acid fermentation in terms of where it occurs, starting substrate, end products, and amount of energy produced. 24. When does fermentation occur?  Where oxygen is not present 25. What is being oxidized and reduced in fermentation?  Oxidized – NADH Reduced – pyruvate or acetaldehyde Contrast this to pyruvate oxidation and Krebs cycle phase.  oxidized – carbon molecules Reduced – NAD + FAD 26. What are the differences between alcoholic fermentation and lactic acid fermentation?