ENERGY AND METABOLISM 1

Transcription

1 ENERGY AND METABOLISM 1 Respiration and Fermentation 1. Some bacteria can use carbon dioxide rather than oxygen as the prime oxidizing molecule and therefore produce methane (CH4) rather than water as a waste product. (T/F) 2. Autotrophs are organisms which can go out and hunt for their own food, unlike plants which stay in one place and absorb sunshine. (T/F) 3. The chemiosmotic hypothesis was formulated by Hans Krebs when he realized there was more to ATP production than glycolysis and the cycle which bears his name. (T/F) 4. Which of the following is NOT an end product of glycolysis? a. ATP b. NADH c. lactic acid d. pyruvic acid 5. The activation energy needed to get glycolysis started is provided by a. vibration energy in the water. b. ATP. c. proton motive force. d. reducing glucose using electrons from NADPH. 6. What is the net gain in ATP molecules per glucose produced during the reactions of glycolysis under anaerobic conditions? a. 2 b. 10 c. 32 d. around How much molecular oxygen is required in the fermentation of one molecule of glucose? a. none b. 1 c. 24 d. 36 e Aerobic respiration oxidizes glucose down to 6 molecules of carbon dioxide. The complete oxidation of individual carbons to carbon dioxide is seen in a. glycolysis b. conversion of pyruvate to acetyl CoA c. Krebs Cycle d. both b and c are correct e. a, b and c are all correct 9. Which of the following statement is NOT true of Krebs Cycle? a. it begins when a molecule of acetyl CoA is attached to a 4 carbon molecule (oxaloacetate) to make a 6 carbon molecule (citrate) b. two substrate phosphorylation events occur per molecule of glucose c. it uses FAD as the only electron acceptor instead of NAD as used in glycolysis d. carbon skeletons may be removed to be used for amino acid biosynthesis 10. The most common product of fermentation in animal cells is a. butanol. b. ethanol. c. lactate. d. pyruvate.

2 ENERGY AND METABOLISM The purpose of fermentation is to a. make more ATP than can be obtained by glycolysis alone. b. complete the oxidation of glucose to carbon dioxide. c. oxidize NADH to NAD so glycolysis can continue d. provide strange byproducts so students can do weird and awful things to their heads. 12. Cyanide blocks the respiratory electron transport chain. As a result a. Krebs Cycle speeds up. b. electrons and hydrogens cannot flow from NADH to oxygen. c. three ATP are produced for every pair of electrons. d. production of water increases. e. glycolysis is inhibited. 13. For a living animal, which of the following compounds has the greatest amount of energy per molecule? a. ATP b. ADP c. H2O d. NADH e. pyruvic acid 14. When a molecule of glucose is completely broken down in a cell to water and carbon dioxide, some ATP molecules are synthesized directly and some by chemiosmotic phosphorylation via the electron transport system. What approximate percentage of the total number of ATP molecules formed comes from the latter process? a. 90% b. 66% c. 50% d. 25% 15. Despite the name, oxygen is not necessarily required for the process that we call oxidation. (T/F) 16. Oxygen is the terminal electron acceptor of the respiratory electron transport chain. (T/F) 17. The presence of excess ADP in the cytoplasm will stimulate glycolysis to proceed at a faster rate. (T/F) 18. Most organisms under certain conditions will use fermentation whose primary purpose is to which is needed in order to continue producing more ATP. a. produce ethanol b. produce carbon dioxide c. reduce NAD d. oxidize NADH A mitochondrion has an outer membrane, an inner membrane, an outer compartment and the inner compartment or matrix. Questions refer to where certain events are happening wither reference to the mitochondrion and its compartments. 19. Krebs cycle occurs in. 20. Glycolysis occurs in.

3 ENERGY AND METABOLISM The molecules of the respiratory electron transport chain are found in 22. The lowest ph would be found in. a. the cytoplasm b. the matrix c. the outer compartment 23. When a muscle cell is metabolizing glucose in the complete absence of molecular oxygen, which of the following substances is NOT produced? a. PGAL b. ATP c. pyruvate d. lactate e. acetyl-coa 24. Which of the following is NOT an end product of Krebs Cycle? a. ATP or ATP equivalents b. citrate c. CO2 d. NADH e. FADH2 25. Which of the following is NOT necessary for Krebs Cycle to run? a. NAD b. oxaloacetate (OAA) c. AcetylCoA d. ATP 26. Which of the following produces the MOST NADH? a. Krebs Cycle b. Glycolysis c. the Respiratory Electron Transport Chain 27. Which of the following is directly responsible for most ATP production under aerobic conditions a. Krebs Cycle b. Glycolysis c. the Respiratory Electron Transport Chain 28. Which of the following is used to donate electrons for anabolic reactions? a. NADH b. FADH2 c. NADPH d. a and b e. a, b and c 29. The preparatory step linking Glycolysis and Krebs cycle directly produces all of the following EXCEPT a. NADH. b. AcetylCoA. c. CO2. d. ATP. 30. During anabolism, sugars are broken down for the production of energy. (T/F) 31. Autotrophic organisms use sunlight as an energy source while heterotrophic organisms must directly or indirectly get their energy from carbon compounds made by autotrophs. (T/F) 32. Although Krebs cycle does not directly use molecular oxygen, it will not be able to function for very long in the absence of oxygen. (T/F) 33. FAD is used in Krebs cycle as a coenzyme to assist the enzymes responsible for directing oxidation reactions. (T/F) 34. Energy is harvested directly from glycolysis in the form of phosphorylation. a. oxidative b. substrate c. photo- 35. The oxidizing agent used in glycolysis is a. NAD. b. NADP. c. oxygen. d. FAD.

4 ENERGY AND METABOLISM Four ATP are produced as a result of glycolysis, but the net yield is only 2 ATP because a. 2 ATP must be used to regenerate the starting materials. b. 2 ATP are used to prepare pyruvate for Krebs Cycle. c. on average, 2 ATP are lost due to spontaneous breakdown. d. 2 ATP were used to activate the glucose in order to start glycolysis. 37. The oxidation of glyceraldehyde-3-phosphate is a crucial step of glycolysis because a. it converts the molecule to pyruvate and thus completes the pathway. b. it releases the energy necessary to attach a phosphate group and make. 1, 3-bisphosphoglycerate. c. it completes the oxidation of one carbon which is released as CO Some bacteria acquire all their energy through fermentation in which glycolysis is not followed by Krebs cycle, but instead pyruvate is reduced to lactate or ethanol in order to a. regenerate the oxidizing agent used in glycolysis b. produce ATP c. prepare to reverse the pathway and make more glucose d. get the bacteria so drunk it doesn't care whether of not it can make ATP 39. Which of the following is NOT true of the preparatory step linking glycolysis and Krebs cycle? a. pyruvate is oxidized b. CO 2 is released c. ATP is made 40. Which of the following is NOT correct about Krebs cycle? a. the starting materials are oxaloacetate and acetyl Co A. b. ATP is made by oxidative phosphorylation c. it completes the oxidation of glucose Definitions. Explain the terms or phrases below with one sentence descriptions. 1. Coupled reaction 2. Substrate-level phosphorylation of ADP

5 ENERGY AND METABOLISM 5 Short Answer 1. Label the expertly rendered sketch of a mitochondrion below to show where (a) glycolysis takes place, (b) where Krebs Cycle takes place, (c) where the respiratory electron transport chain is located and (d) which compartment is the most acidic and (e) which compartment is called the matrix? What happens to the CO2 that is generated as a waste product by this organelle? 6 points 2. Peter Mitchell developed the "Chemiosmotic Hypothesis" to explain how ATP is generated in the mitochondria. Briefly describe the role of the electron transport chain in the inner mitochondrial membrane in generating the H+ gradient necessary for chemiosmosis to work. How is this gradient used to make ATP? And what is the role of molecular oxygen in this process? A neatly drawn and clearly labeled sketch would be a good way to answer this question.