1. Introduction to Cell Respiration chp 7 Life is Work!!!

2. Photosynthesis  Energy in ecosystems first comes from sun

3. 2 nd Law thermodynamics  Universe is all going to lower energy!  NOT LIFE  Living things work to combat entropy  Photosynthesis energy must be stored and used to prevent loss as heat

4. Cellular respiration  Process of harvesting chemical energy to do work  Autotrophs – (Plants) capture sunlight and form organic compounds (photosynthesis)  Heterotrophs (animals, fungi etc) (and autotrophs) use this energy

5. Respiration uses the chemical energy from photosynthesis

6. Respiration In Mitochondria  Uses O 2  Uses Sugar (Org. comp) Produces CO 2 Sugar  ATP Photosynthesis In Chloroplasts  Produces O 2  Produces Sugar (Org. Comp) Uses CO 2 Light  Sugar

7. Cell Respiration  Use of Sugar and Oxygen to produce ATP energy for life functions

8. MOST energy in respiration is Still lost as heat

9. SOME free energy is formed into ATP  ATP production is the goal of cell respiration

10. Cell Respiration is “like” fire Fire needs Respiration needs Wood and OxygenGlucose and Oxygen BUT respiration is SLOW and Using redox reactions

11. Redox reactions  Breakdown of food requires oxidation  Oxidation is the loss of electrons  Reduction is the gain of electrons.  These reactions are usually coupled together

12. NAD+ Nicotinamide Adenine Dinucleotide NAD+ is the main energy molecule used to make ATP  NAD+ is an enzyme cofactor  In the process of glucose breaking down A redox reaction causes it to gain electrons and H+, energizing it  NAD+  NADH

13. NADH – forms ATP  Electron transport chain  At the end of respiration electrons are released from NADH by electron transport chain which powers production of ATP

14. Two types of respiration  Aerobic respiration – if electron acceptor is oxygen  Anaerobic respiration – no oxygen

15. Fermentation  When there is NO oxygen  Called Anaerobic respiration  Catabolic process breaking organic compounds  Produces only 2 ATP

16. Aerobic Respiration happens in the mitochondria  Uses oxygen and process a lot of ATP

17. Respiration  Sugar + Oxygen  Carbon Dioxide + Water + ATP  C 6 H 12 O 6 + O 2  CO 2 + H 2 O + ATP

18. Stages of respiration 1) Glycolysis – Glucose breaks into 2 pyruvates and forms 2 ATP. 2) Krebs Cycle – Pyruvate is broken into C0 2 molecules and forms 2 ATP and NADH and FADH 2 (H+ carriers) 3) Electron Transport Chain – NADH and FADH 2 produce 34 ATP, using up oxygen and producing water.

19. Sites of Cellular Respiration  1) Glycolysis in cytoplasm  2) Krebs cycle in mito. Matrix  3) ETC in inner mito. membrane

20. Electron Transport Chain (system) Electron Transport Chain (system)  Occurs in the inner Mitochondria membrane  NADH and FADH 2 are Oxidized (lose electrons) to form 34 ATP  Oxygen is used up (final electron acceptor)  Water is produced from H + and OH-

21. ETC molecules :  Energy molecules NADH and FADH 2 carry H + and e - to Inner Mito. membrane where there are a lot of protein complexes

22. ETC electron flow  Electrons flow along protein chain in inner membrane  At End, Oxygen accepts electrons forming water

23. 1 st - NADH and FADH 2 are oxidized  Electrons are removed releasing energy which is used to pump H+ protons from matrix into the inter membrane space.  Electrons travel through ETC

24. 2 nd – H+ Protons flow back into matrix through ATP synthase High H+ concentration pushes H+ ions through ATP synthase which spins like a rotary engine, producing ATP. Called chemiosmosis

25. Chemiosmosis  The diffusion of ions across a selectively- permeable membrane. Usually it generates ATP by the movement of hydrogen ions across a membrane during cellular respiration. ionsATP hydrogenmembraneionsATP hydrogenmembrane

26. ATP formed by Oxidative phosphorylation in electron transport chain  ATP synthase phosphorylates ADP using proton gradient pump in inner mitochondrial membrane  OXIDATION NOT substrate level phosphorylation

27. Oxygen. The Final electron acceptor  At end of ATP phosphorylation, Oxygen accepts the electrons from the ETC and combines with the H+ ions forming water as a by product of respiration  With out oxygen to accept electrons, the ETC would not take place

28. ATP amounts  NADH – forms 3 ATP each  FADH 2 – forms 2 ATP each (starts farther down the ETC)  Note – NADH produced in cytosol must use one ATP to transport into mitochondria

29. Summary of Cell respiration  Cell Respiration Harvests as much free energy (ATP) from sugar as possible  Redox reactions produce NADH which then makes ATP in electron transport  ATP is used in cells for all endergonic reactions