1. Lecture 19: Cellular Respiration.
IB 150 Lecture 17
Lecture 19: Cellular Respiration.  
By the end of this lecture you should be able to…
Describe respiration as a redox reaction.
Concepts and terms: reductant, oxidant, NADH
Describe the structure of mitochondria
Discuss the major components of cellular respiration.
Concepts and terms: glycolysis, Krebs cycle, electron transport
Describe the major inputs and products of each component of the respiratory pathway.
Describe chemiosmosis.
Concepts and terms: ATP synthase, proton gradient.
Contrast aerobic and anaerobic respiration.
Concepts and terms: fermentation, lactic acid
Describe the role of inhibitors in studying respiratory biochemistry.
Assigned reading: Chapter 9 in the text.
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2. IB 150 Lecture 17
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3. IB 150 Lecture 17
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4. Mitochondria are the cells' power sources.
IB 150 Lecture 17
Mitochondria are the cells' power sources.
Usually they are rod-shaped; however they can be round.
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5. C6H12O6 + 6O2 6CO2 + 6 H2O Cellular respiration: IB 150 Lecture 17
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6. NAD: nicotinamide adenine dinucleotide
IB 150 Lecture 17
NAD: nicotinamide adenine dinucleotide
Electrons from food are transferred initially to NAD+
Some of the energy released from NADH is used to make ATP
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7. IB 150 Lecture 17
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8. IB 150 Lecture 17
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9. IB 150 Lecture 17
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10. Substrate-level phosphorylation
IB 150 Lecture 17
Substrate-level phosphorylation
Oxidative phosphorylation
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11. IB 150 Lecture 17
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12. IB 150 Lecture 17
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13. Figure 9.11 A closer look at the Krebs cycle (Layer 1)
IB 150 Lecture 17
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14. Figure 9.11 A closer look at the Krebs cycle (Layer 2)
IB 150 Lecture 17
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15. Figure 9.11 A closer look at the Krebs cycle (Layer 3)
IB 150 Lecture 17
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16. Figure 9.11 A closer look at the Krebs cycle (Layer 4)
IB 150 Lecture 17
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17. IB 150 Lecture 17
The conversion of pyruvate and the Krebs cycle produces large quantities of electron carriers.
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18. IB 150 Lecture 17
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19. IB 150 Lecture 17
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20. Chemiosmosis Peter Mitchell (1920 - 1992) Nobel Laureate…
IB 150 Lecture 17
Peter Mitchell ( ) Nobel Laureate…
…1961 paper introducing the chemiosmotic hypothesis.
Mitchell's proton pumping loops
Mitchell suggested that electron transport chains could act as proton pumps if they contained alternate electron carrying and H-carrying spans of redox couples arranged so as to transport electrons and hydrogen vectorially across the membrane.
The reduction of a H-carrier by an electron carrier in one phase would lead to uptake of H+; the diffusion of the H-carrier (as a neutral species) across the membrane, and its oxidation on the other side by an electron carrier would lead to release of a H+; electron transfer back across the membrane would carry a -ve charge across the membrane in the opposite direction, thus allowing the loop to carry 1 H+ (net) in an electrogenic proton pumping loop.
Chemiosmosis
Fall Semester 2001

21. Oxidative phosphorylation
IB 150 Lecture 17
Proton-motive force
Oxidative phosphorylation
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22. IB 150 Lecture 17
A protein complex, ATP synthase, in the cristae actually makes ATP from ADP and Pi.
ATP used the energy of an existing proton gradient to power ATP synthesis.
This proton gradient develops between the intermembrane space and the matrix.
Fig. 9.14
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
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23. IB 150 Lecture 17
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24. IB 150 Lecture 17
Aerobic
Anaerobic
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25. During extreme exertion…
IB 150 Lecture 17
During extreme exertion…
Initially, stored ATP is metabolized (~5mmol/kg muscle. It’s gone in about 5 s.
Then phosphocreatine is converted to ATP; gone in another 5 s.
Then glycolosis starts (anaerobic respiration)…oops, lactate accumulates.
Anaerobic respiration kicks in after about 2 min.
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26. Feedback mechanisms control cellular respiration
IB 150 Lecture 17
Feedback mechanisms control cellular respiration
Fall Semester 2001