1. CELLULAR RESPIRATION CH 9

2. All cells require energy from an outside source Some organisms obtain energy by producing it (photoautotrophs and chemoautotrophs) Some organisms obtain energy by consuming other organisms (heterotrophs)

3. What does this diagram tell?

4. energy enters ecosystem as sun and leaves as heat photosynthesis uses sunlight to make glucose which is used in cell respiration cell respiration makes ATP which is used for work

5. I. Catabolism of glucose Cellular respiration = catabolism of glucose to produce ATP Is a series of redox reactions 3 types of cellular respiration: Aerobic respiration (nearly all organisms) Anaerobic respiration (only a few types of bacteria) Fermentation (when aerobic can’t work)

6. II. Aerobic Respiration A. Overview

7. Requires O2 Occurs in most organisms In eukaryotes, most of it occurs in the mitochondria Produces 36 ATP Occurs in 4 stages: – Glycolysis – Oxidation of pyruvate – Kreb’s citric acid cycle – Electron transport chain and oxidative phosphorylation

8. B. Redox and Cell Respiration Glucose gives up electrons to NAD+ and FAD+ – Glucose is oxidized and NAD+ and FAD+ get reduced NADH and FADH2 donate electrons to ETC and then to O2 – NADH and FADH2 become oxidixed and O2 becomes reduced

9. C. Stages of Aerobic Respiration 1. Glycolysis: oxidizes glucose to pyruvate

10. Occurs in ALL cells Is anaerobic Occurs in the cytoplasm Breaks down glucose to 2 3-carbon molecules called pyruvate Electrons from glucose are donated to NAD+ making NADH

11. 2. Oxidation of Pyruvate

12. Converts pyruvate to acetyl CoA linking glycolysis to citric acid cycle Electrons from pyruvate are donated to NAD+ making NADH Occurs in the mitochondria

13. 3. Kreb’s citric acid cycle cycle Occurs in the mitochondrial matrix Electrons from molecules in citric acid cycle are used to reduce NAD+ and FAD+ to NADH and FADH2 http://highered.mcgraw- hill.com/sites/0072507470/student_view0/ch apter25/animation__how_the_krebs_cycle_w orks__quiz_1_.html

14. 4. Electron Transport Chain http://www.science.smith.edu/departments/Biology/Bio231/etc.html http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter9/

15. Occurs on inner membrane of mitochondria At this point, majority of energy from food is in NADH and FADH2 NADH and FADH2 donate e- to ETC which moves thru a series of proteins by redox NRG in e- is used to actively pump protons across the inner membrane As the protons diffuse down their concentration gradient, ATP synthase uses the energy in the gradient to make 32ATP by chemiosmotic phosphorylation O2 is final acceptor of e-. It becomes reduced to water

16. D. Compare Chemiosmosis in photosynthesis and respiration In both, electrons are shuttled thru ETC and protons are pumped up their gradient. As the protons diffuse thru ATP synthase ATP Iis made

17. Aerobic respiration: the big picture

18. III. Regulation of Aerobic Respiration By feedback regulation

19. High ATP means cell has enuf ATP and ATP acts like allosteric inhibitor to turn off 2nd enzyme in glycolysis (phosphofructokinase) High NADH means not enuf O2 and ETC is shutting. NADH acts as allosteric inhibitor to the oxidation of pyruvate High ADP means cell needs more ATP and ADP acts as allosteric activator to activate phosphofructokinase

20. Aerobic respiration in prokaryotes Same 4 parts but ETC occurs on cell membrane and everything else in cytoplasm

21. IV. Anaerobic respiration Occurs in certain bacteria (abligate anaerobes) Has the same stages as aerobic respiration However, O2 is NOT the final e- acceptor.

22. V. Fermentation

23. Without O2 ETC shuts Pyruvates from glycolysis enter into fermentation Produces limited ATP (only 2) when compared to aerobic respiration NADH produced in glycolysis is converted back to NAD to keep glycolysis running 2 types: lactic acid fermentation and alcoholic fermentation

24. 1. Lactic acid fermentation Occurs in muscle cells Produces lactic acid 2. Alcoholic fermentation Occurs in yeast cells Produces alcohol and CO2

25. VI. RELATIONSHIP BETWEEN PHOTOSYNTHESIS AND RESPIRATION