1. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R O B I O L O G Y a n i n t r o d u c t i o n ninth edition TORTORA  FUNKE  CASE Part A 5 Microbial Metabolism

2. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Metabolism: The sum of the chemical reactions in an organism  Catabolism: The energy-releasing processes  Anabolism: The energy-using processes Microbial Metabolism

3. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Microbial Metabolism  Catabolism provides the building blocks and energy for anabolism. Figure 5.1

4. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  A metabolic pathway is a sequence of enzymatically catalyzed chemical reactions in a cell.  Metabolic pathways are determined by enzymes.  Enzymes are encoded by genes. PLAY Animation: Metabolic Pathways (Overview)

5. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Activation energy is needed to disrupt electronic configurations.  Reaction rate is the frequency of collisions with enough energy to bring about a reaction.  Reaction rate can be increased by enzymes or by increasing temperature or pressure.

6. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Enzymes Figure 5.2

7. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Enzymes  Biological catalysts  Specific for a chemical reaction; not used up in that reaction  Apoenzyme: Protein  Cofactor: Nonprotein component  Coenzyme: Organic cofactor  Holoenzyme: Apoenzyme plus cofactor

8. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Enzymes Figure 5.3

9. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Important Coenzymes  NAD +  NADP +  FAD  Coenzyme A

10. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Enzymes  The turnover number is generally 1-10,000 molecules per second. PLAY Animation: Enzyme–Substrate Interactions Figure 5.4

11. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.4 - Overview

12. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Enzymes can be denatured by temperature and pH Figure 5.6

13. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Temperature Figure 5.5a

14. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  pH Figure 5.5b

15. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Substrate concentration Figure 5.5c Saturation

16. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Competitive inhibition Figure 5.7a–b Examples: Poisons such as cyanide, arsenic, and mercury.

17. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity

18. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Noncompetitive inhibition Figure 5.7a, c Example: Fluoride

19. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Factors Influencing Enzyme Activity  Feedback inhibition Figure 5.8

20. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Oxidation-Reduction  Oxidation is the removal of electrons.  Reduction is the gain of electrons.  Redox reaction is an oxidation reaction paired with a reduction reaction. Figure 5.9

21. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 5.10

22. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Generation of ATP  ATP is generated by the phosphorylation of ADP.

23. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Generation of ATP  Substrate-level phosphorylation is the transfer of a high-energy PO 4 3– (PO 4 H 2 – ) to ADP.

24. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Generation of ATP  Oxidative Phosphorylation:  Energy released from the transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP by chemiosmosis.

25. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemiosmosis

26. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Generation of ATP  Photophosphorylation:  Light causes chlorophyll to give up electrons. Energy released from the transfer of electrons (oxidation) of chlorophyll through a system of carrier molecules is used to generate ATP.

27. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Photophosphorylation

28. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Metabolic Pathways

29. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Carbohydrate Catabolism  The breakdown of carbohydrates to release energy  Glycolysis  Krebs cycle  Electron transport chain

30. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Glycolysis  The oxidation of glucose to pyruvic acid produces ATP and NADH. Figure 5.11, step 1

31. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Glycolysis  Glucose + 2 ATP + 4 ADP + 2 PO 4 – + 2 NAD +  2 pyruvic acid + 4 ATP + 2 NADH + 2H + PLAY Animation: Glycolysis

32. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cellular Respiration  Oxidation of molecules liberates electrons for an electron transport chain.  ATP is generated by oxidative phosphorylation.

33. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Krebs Cycle  Oxidation of acetyl CoA produces NADH and FADH 2. PLAY Animation: Krebs Cycle

34. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings The Electron Transport Chain  A series of carrier molecules that are, in turn, oxidized and reduced as electrons are passed down the chain.  Energy released can be used to produce ATP by chemiosmosis. PLAY Animation: Electron Transport Chains and Chemiosmosis

35. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemiosmosis Figure 5.16

36. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Chemiosmosis Figure 5.15

37. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Respiration  Aerobic respiration: The final electron acceptor in the electron transport chain is molecular oxygen (O 2 ).  Anaerobic respiration: The final electron acceptor in the electron transport chain is not O 2. Yields less energy than aerobic respiration because only part of the Krebs cycles operations under anaerobic conditions.

38. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Electron acceptorProducts NO 3 – NO 2 –, N 2 + H 2 O SO 4 – H 2 S + H 2 O CO 3 2 – CH 4 + H 2 O Anaerobic Respiration

39. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PathwayEukaryoteProkaryote GlycolysisCytoplasm Krebs cycleMitochondrial matrixCytoplasm ETC Mitochondrial inner membrane Plasma membrane Location Comparison

40. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Pathway By substrate- level phosphorylation By oxidative phosphorylation From NADH From FADH Glycolysis260 Intermediate step06 Krebs cycle2184 Total4304  ATP produced from complete oxidation of one glucose using aerobic respiration.  36 ATPs are produced in eukaryotes.