How living organisms harvest and utilize energy

1. How living organisms harvest and utilize energy

2. Teachable Unit • How living organisms harvest and utilize energy • Learning Goals: • 1. Students will be able to define chemical energy, proton gradient, • chemiosmosis, ATP, oxidation and reduction. • 2. Students will be able to explain the importance of reduction and • oxidation by the electron transport chain in the generation of • the proton gradient across the inner mitochondrial membrane. • 3. Students will be able to predict what will happen to the rate of • ATP synthesis under the following conditions: • - elimination of the proton gradient; • - inhibition of electron transport; • - diminished oxygen levels. • 4. Students will be able to describe the importance of chemiosmosis • to the production of ATP.

3. A Teachable Tidbit #1:Electrons and protons – Pass it on! Addressing different learning styles in an introductory biology classroom

4. Learning Goal: Students will be able to explain the importance of reduction and oxidation by the electron transport chain in the generation of the proton gradient across the inner mitochondrial membrane.

5. Learning outcomes of Tidbit #1 Students will be able to illustrate a model of the flow of electrons through the electron transport chain. Students will be able to describe the dynamic nature of electron transport and the generation of the proton gradient across the inner mitochondrial membrane.

6. Prior Learning/Assumptions Students have already completed readings, lectures, and in discussions: - Glycolysis - Citric acid cycle - Electron transport - Oxidative phosphorylation

7. 1. The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is: A) pyruvate B) water C) NAD+ D) oxygen

8. 2. When electrons flow down the mitochondrial electron transport chain (ETC) which of the following occurs? A) The pH of the matrix increases. B) The electrons gain free energy. C) NAD+ is oxidized.

9. 3. Flow of electrons down the electron transportchain directly causes: ATP synthesis. formation of a proton gradient. NADH reduction. production of CO2.

10. 4. In the presence of a metabolic poison thatspecifically and completely blocks electron flow down the ETC, which would you expect? A) a decrease in the pH difference across the inner mitochondrial membrane B) increased oxygen consumption and water production C) an increased rate of accumulation of NAD+

11. ATP for life http://static-p4.fotolia.com/jpg/00/06/63/71/400_F_6637167_Zcosvn3nSERcbR654K5uQfSC3MIndmA2.jpg http://www.magicsoil.com/Zucchini%20Plant,%20with%20seed%20pod%20on%20top,%203-15-06.jpg http://www.honda-e.com/IPW_6_PhotoGallery/04_Dionaea/PHOTO_JPEG/Flytrap002%20copy.jpg http://www.tribuneindia.com/2005/20050816/sp2.jpg

12. Coupling of ATP synthesis to electron transfer

13. Coupling of ATP synthesis to electron transfer ATP ATP ATP H+ H+ H+ H+ Cyt c Q IV I III ATP synthase II H2O FADH2 2 H+ + 1/2 O2 FAD+ NADH+ NAD+ ATP ADP + P i Electrons from reduced carbon H+ Electron transport chain Electron transport and pumping of protons (H+) to establish a transmembrane H+ gradient Chemiosmosis ATP synthesis driven by the flow of H+ back across the membrane

14. 1. The final electron acceptor of the electron transport chain that functions in oxidative phosphorylation is: A) pyruvate B) water C) NAD+ D) oxygen

15. 2. When electrons flow down the mitochondrial electron transport chain (ETC) which of the following occurs? A) The pH of the matrix increases. B) The electrons gain free energy. C) NAD+ is oxidized.

16. 3. Flow of electrons down the electron transportchain directly causes: ATP synthesis. formation of a proton gradient. NADH reduction. production of CO2.

17. 4. In the presence of a metabolic poison thatspecifically and completely blocks electron flow down the ETC, which would you expect? A) a decrease in the pH difference across the inner mitochondrial membrane B) increased oxygen consumption and water production C) an increased rate of accumulation of NAD+

18. Learning Goal: Students will be able to explain the importance of reduction and oxidation by the electron transport chain in the generation of the proton gradient across the inner mitochondrial membrane.

19. Diversity considerations: • Animation with narration addresses visual and • audial learners • Activity addresses kinesthetic learners • As many students can be involved as want to be • Assessment of reading and prior learning • Repeated assessment after activity • The focus of this activity was on ETC dynamics. However, this could easily be linked to several human health problems that have been shown to be associated with mitochondrial defects. Examples include Parkinson’s, bipolar disorder, and obesity.

20. Dinitrophenol (2,4-DNP), a yellow food dye, was once routinely added to commercial baked goods to make them appear "egg rich." In 1933, this manufactured chemical was introduced as a treatment for obesity. DNP helped patients lose weight. This proved to be very dangerous; many users suffered injury and death due to elevated body temperature. Over one hundred thousand people took these “anti-fat medicines” before they were abandoned in 1937.