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1. Chapter 9 – Harvesting chemical energy What pathways capture chemical energy for cellular work?
What are the inputs and outputs for each pathway?
Where in the cell are these pathways located?
Under what conditions do these pathways operate?
How are these pathways regulated?
How do these pathways connect with the rest of cellular metabolism?
2. Cellular Energy Pathways Carbs ? 6 carbon sugars – organic carbon
Pyruvate ? 3 carbon sugarCarbs ? 6 carbon sugars – organic carbon
Pyruvate ? 3 carbon sugar
3. Energy metabolism in prokaryotes Living organisms must have some way to capture energy
- Food is the electron donors who donate electrons to carriers (NADH) which give it to the transport chain. Living organisms must have some way to capture energy
- Food is the electron donors who donate electrons to carriers (NADH) which give it to the transport chain.
4. Sequence of reactions create incremental releases of energy which eventually creates ATPSequence of reactions create incremental releases of energy which eventually creates ATP
5. Proton gradient across the plasma membrane drives chemisosmotic ATP synthesis (oxidative phosphorylation) and other reactions in prokaryotes ATP synthesis is in the mitochondria ? active transport reactionsATP synthesis is in the mitochondria ? active transport reactions
6. Cellular locations of energy pathways
7. Q: ATP is a short-term energy-storage compound.
the cell’s principle compound for energy transfers.
a molecule all living cells rely on to do work.
one of the four building blocks of RNA
all of the above
8. Structures of ATP, ADP and AMP
9. Oxidized and reduced forms of NAD A lot of potential energy in NADHA lot of potential energy in NADH
10. Initial steps of glycolysis use 2 ATPs, split glucose to 2 G3P
11. Q: In the first reaction of glycolysis, hexokinase couples phosphorylation of glucose to hydrolysis of ATP. The phosphorylation of glucose has a free energy change of +3.3 kcal/mol, whereas the hydrolysis of ATP has a free energy change of -7.3 kcal/mol. This coupled reaction is: respiration.
a redox reaction.
overall exergonic.
overall endergonic.
fermentation.
12. As 2 G3Ps are oxidized to 2 pyruvates, 2 NADH are produced...
13. ...and 4 ATPs
14. ATP synthesis by substrate-level phosphorylation
15. Q: During glycolysis, for each mole of glucose oxidized to pyruvate 6 moles of ATP are produced.
4 moles of ATP are used, and 2 moles of ATP are produced.
2 moles of ATP are used, and 4 moles of ATP are produced.
2 moles of ATP are used, and 2 moles of ATP are produced.
net 4 moles of ATP are produced.
16. Changes in free energy during glycolysis GOOD GRAPH!!!!!!!!
Oxidation to CO2 is -636 kcal/molGOOD GRAPH!!!!!!!!
Oxidation to CO2 is -636 kcal/mol
17. Q: To maintain glycolysis at a high rate, a non-respiratory cell must generate: NADH.
Oxygen.
More ATP.
Acetyl-CoA.
NAD+. A non-respiratory cell needs to generate NAD+ because that will run out during high rates of glycolysis due to the rapid use of NAD+ in creating NADH!!!!A non-respiratory cell needs to generate NAD+ because that will run out during high rates of glycolysis due to the rapid use of NAD+ in creating NADH!!!!
18. Fermentation converts pyruvate to lactic acid or ethanol Fermentation occurs when there is no respirationFermentation occurs when there is no respiration
20. Overview of eukaryotic energy pathways
21. Q: Which photo shows plant mitochondria?
22. In aerobic conditions, pyruvate is oxidized to acetyl CoA Oxidize pyruvate and transfer electrons
Take a Carbon from Pyruvate to create CO2Oxidize pyruvate and transfer electrons
Take a Carbon from Pyruvate to create CO2
23. Citric acid cycle generates ATP, NADH and FADH2 by oxidizing acetate to CO2 TCA cycle or Krebs cycle ? occurs in the mitochondrial matrix
Know the main inputs (acetyl CoA created from pyruvate) ? and know the main outputs (ATP, NADH, CO2, FADH2)TCA cycle or Krebs cycle ? occurs in the mitochondrial matrix
Know the main inputs (acetyl CoA created from pyruvate) ? and know the main outputs (ATP, NADH, CO2, FADH2)
24. Citric acid cycle releases (and captures) more free energy than does glycolysis Captured all of the available energy in glucoseCaptured all of the available energy in glucose
25. Q: Which of the following is produced during the citric acid cycle? FAD
Pyruvate
Reduced electron carriers
Lactic acid
Water
26. Citric acid cycle inputs and products Inputs: Acetate (as acetyl-CoA), water, NAD+ and FAD, ADP, Pi
Products: CO2, NADH, FADH2, ATP
per glucose (2 acetyl-CoA enters cycle):
4 CO2, 6 NADH + 6 H+, 2FADH2, and 2ATP are generated
Some free energy is captured as GTP/ATP, but most as reduced electron carriers NADH, FADH2 Important ? STUDY THIS!!!Important ? STUDY THIS!!!
27. Respiration charges a proton gradient & powers ATP synthesis via chemiosmosis ~10 protons pumped across the membrane per NADH~10 protons pumped across the membrane per NADH
28. Free energy changes in the respiratory chain BE aware of: Terminal Electron Acceptor ? OxygenBE aware of: Terminal Electron Acceptor ? Oxygen
29. Chemiosmotic synthesis of ATP
30. The F1 ATPaseHarvard Video www.sigmaaldrich.com/Area_of_Interest/Life_science/metabolomics/key_resources/metabolic_pathwayswww.sigmaaldrich.com/Area_of_Interest/Life_science/metabolomics/key_resources/metabolic_pathways
31. Total ATP production from glycolysis and respiration The times 2 is because each glucose creates 2 pyruvates and therefore 2 acetyl CoA’s
Mitochondria: 8*3 = 24 ATP’s
4 ATP from FADH
2 ATP
36-38 ATP per glucose overallThe times 2 is because each glucose creates 2 pyruvates and therefore 2 acetyl CoA’s
Mitochondria: 8*3 = 24 ATP’s
4 ATP from FADH
2 ATP
36-38 ATP per glucose overall
32. Q: How will excess acetyl-CoA affect the rates of glycolysis and the citric acid cycle?
Both will increase
Both will decrease
Glycolysis will increase, citric acid cycle will decrease
Glycolysis will decrease; the citric acid cycle will increase
Neither will change
33. Q: During intense exercise, as muscles go into anaerobiosis, the body will increase its consumption of:
fats
proteins
carbohydrates
All of the above Citric acid cycle and pyruvate oxidation do not occur in anaerobiosis.Citric acid cycle and pyruvate oxidation do not occur in anaerobiosis.
34. What do the following have in common? Both have specialized mechanisms for thermal regulationBoth have specialized mechanisms for thermal regulation
35. Q: Petite mutants of yeast have defective mitochondria incapable of oxidative phosphorylation. What carbon sources can these mutants use to grow?
Glucose
Fatty acids
Pyruvate
All of the above
None of the above
Concept 9.6 (7th ed)
Concept 9.6 (7th ed)
36. Thermogenesis in philodendrons
37. Brown fat in newborn mammals Maintains body temperature after leaving the womb ? mostly fat cells permeated with red blood vessels. Thermogenin or mito uncoupling potein ? facilitated diffusion of protons across the membrane .
All this energy is wasted as heat ? only purposeMaintains body temperature after leaving the womb ? mostly fat cells permeated with red blood vessels. Thermogenin or mito uncoupling potein ? facilitated diffusion of protons across the membrane .
All this energy is wasted as heat ? only purpose
38. Q: Some drugs known as uncouplers facilitate diffusion of protons across the mitochondrial inner membrane. When such a drug is added, what will happen to ATP synthesis and oxygen consumption?
Both ATP synthesis and oxygen consumption will decrease
ATP synthesis will increase, oxygen consumption will decrease
Both ATP synthesis and oxygen consumption will increase
ATP synthesis will decrease, oxygen consumption will stay the same
There will be no effect on ATP synthesis or oxygen consumption