Honors Biology Chapter 6.8 6.12 Study Sheet The Citric Acid Cycle and Oxidative Phosphorylation PYRUVATE OXIDATION DRAW THE DETAILED REACTION BELOW: REACTION SUMMARY: SUBSTRATES: PRODUCTS: THE CITRIC ACID CYCLE (KREBS CYCLE): THE DETAILS DRAW THE DETAILED REACTION BELOW: REACTION SUMMARY: SUBSTRATES: PRODUCTS:
1. How many carbons from the original glucose enter the Krebs cycle? These carbons enter as what molecule? 2. How many times does the Krebs cycle turn per glucose molecule? 3. Where are all the carbons from the original glucose following the Krebs cycle? 4. Where is all the energy from the bonds of glucose following its oxidation in the Krebs cycle? THE ETC: THE DETAILS SUMMARY OF EVENTS: WHERE DO H+ ACCUMULATE? WHICH WAY DO H+ CROSS TO GENERATE ATP?
5. The ETC consists of a series of proteins and enzymes called. These proteins are embedded in the membrane of mitochondria. 6. The ETC separates hydrogen atoms into and. Electrons are transferred, step by step through the chain until the electrons are combined with to form. Thus oxygen serves as the final electron acceptor. 7. Just like in photosynthesis, the transfer of electrons thru each step in the chain releases a small amount of free energy which is used to transport from the to the space. Thus protons become concentrated in the innermembrane space of the mitochondria. 8. The production of a proton gradient creates a large source of potential energy which is then used to synthesize ATP. As protons cross back through the mitochondrial membrane, they can do so only through the enzyme complex. ATP is thus synthesized from ADP and phosphate using the energy of letting a proton back through. 9. NADH can drives the synthesis of 2.5 molecules of ATP, whereas FADH2 can drive the synthesis of up to 1.5 molecules of ATP. THE BALANCE BOOK OF ATP SYNTHESIS PROCESS Glycolysis NUMBER OF ELECTRON CARRIERS PRODUCED # ATP MOLECULES FORMED BY: DIRECT ATP OXIDATION OF SYNTHESIS ELECTRON CARRIERS (SUBSTRATE- IN ETC LEVEL PHOS.) TOTAL ATP MOLECULES Pyruvate to Acetyl-CoA Krebs cycle FADH 2 Total ATP per glucose molecule TEST YOUR KNOWLEDGE 1. In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs? (6.8) A. Oxygen atoms are formed into oxygen gas. B. A compound called coenzyme A binds to a two-carbon fragment from the pyruvate C. Pyruvate is reduced by oxidizing an NAD+ to an NADH. D. Carbon dioxide must be present for pyruvate to enter the citric acid cycle. 2. When pyruvate is converted to acetyl CoA,. (6.8) A. one turn of the citric acid cycle is completed B. CO2 and coenzyme A are formed C. CO2 and ATP are formed D. CO2 and NADH are formed
3. A scientist wants to study the enzymes of the citric acid cycle in eukaryotic cells. What part of the cell would she use as a source of these enzymes? (6.9) A. plasma membrane B. mitochondrial matrix C. mitochondrial inner membrane D. cytoplasm 4. What molecule is required to move pyruvate to the citric acid cycle? (6.9) A. NADH B. FADH2 C. O2 D. ATP 5. Most of the NADH that delivers high-energy electrons to the electron transport chain comes from. (6.9) A. the citric acid cycle B. glycolysis C. chemiosmosis D. the cytoplasm 6. Why is the citric acid cycle called a cycle? (6.9) A. NAD+ and FAD are recycled. B. Acetyl CoA binds to oxaloacetate that is restored at the end of the cycle. C. Glucose is cycled around and resynthesized. D. NADH is recycled in the electron transport chain. 7. The energy production per glucose molecule through the citric acid cycle is. (6.9) A. 2 ATP, 6 NADH B. 4 ATP, 8 NADH C. 2 ATP, 6 NADH, 2 FADH2 D. 38 ATP 8. Once the citric acid cycle has been completed, most of the usable energy from the original glucose molecule is in the form of. (6.9) A. ATP B. NADH C. acetyl CoA D. CO2 9. In oxidative phosphorylation, electrons are passed from one electron carrier to another. The energy released is used to. (6.10) A. pump protons (H+) across the mitochondrial membrane B. generate large amounts of NADH and FADH2 C. form ATP during glycolysis D. synthesize carbon dioxide 10. What is the fate of the electrons that are stripped from glucose during cellular respiration? (6.10) A. They are used to form ATP by chemiosmosis. B. They are donated to NADH. C. They are used to form water. D. They result in the formation of heat.
11. In cellular respiration, which of the following is performed directly by the electron transport chain (or its components)? (6.10) A. ADP is phosphorylated to make ATP. B. Carbon dioxide is formed. C. A proton gradient is formed. D. Oxygen gas is formed. 12. In a eukaryotic cell, the electron transport chain is precisely located in or on the. (6.10) A. cytoplasmic fluid B. intermembrane space of the mitochondrion C. cristae of the mitochondrion D. plasma membrane 13. Dinitrophenol (DNP) is a highly toxic membrane uncoupler. What happens when DNP makes the phospholipid bilayer of inner mitochondrial membranes permeable to protons (H+)? (6.11) A. The redox reactions of the electron transport chain cease. B. The proton pumps of the inner mitochondrial membrane would cease to function. C. NADH or FADH2 would no longer provide electrons to the electron transport chain. D. Many protons would bypass ATP synthase, leading to a sharp decline in ATP synthesis. 14. Which of the following directly requires molecular oxygen (O2)? (6.12) A. the electron transport chain B. glycolysis C. chemiosmosis D. the citric acid cycle 15. Substrate-level phosphorylation directly generates ATP during a chemical reaction. As a single molecule of glucose is completely oxidized, in the presence of oxygen, how many molecules of ATP are gained by substrate-level phosphorylation? (6.12) A. 4 ATP B. 6 ATP C. 2 ATP D. 38 ATP