1. © 2004 Wadsworth – Thomson Learning Chapter 5 Metabolism of Microorganisms

2. © 2004 Wadsworth – Thomson Learning Metabolism in the cell Figure 5.1

3. © 2004 Wadsworth – Thomson Learning Biosynthesis in a cell Composition of cell –protein –RNA –DNA –Lipid –Lipopolysacharide –Peptidoglycan –Glycogen –Small molecules –Ions Figure 5.2

4. © 2004 Wadsworth – Thomson Learning Transport into the cell Outer membrane –pass through porin small size concentration gradient Cell wall –mesh-like –diffuse through Cell membrane –transporters Figure 5.3

5. © 2004 Wadsworth – Thomson Learning Oxidation/Reduction Reactions Reducing power used in metabolism –Oxidation loss of electrons –Reduction gain of electrons –reactions linked one molecule reduced one molecule oxidized Figure 5.5

6. © 2004 Wadsworth – Thomson Learning ATP: Biological Energy Adenosine triphosphate –negative charged phosphates repel –high energy bonds hold together –breaking bond to remove phosphate releases energy ATP –high energy ADP –low energy Figure 5.6

7. © 2004 Wadsworth – Thomson Learning Substrate level phosphorylation ADP obtains phosphate from metabolic intermediate –molecule which has a high energy bond ATP is formed Figure 5.7

8. © 2004 Wadsworth – Thomson Learning Glycolysis Start –6-carbon sugar (glucose) Energy input –two phosphorylations –2 ATP used for each glucose Cleave –two 3-carbon molecules Figure 5.9

9. © 2004 Wadsworth – Thomson Learning Glycolysis Reductions –two NAD+ are reduced –produce electron carriers Substrate level phosphorylation –2 ATP produced for every glucose Figure 5.9

10. © 2004 Wadsworth – Thomson Learning Glycolysis Dehydration –water removed Substrate level phosphorylation –2 more ATP produced End products –2 pyruvates –3-carbon molecules Figure 5.9

11. © 2004 Wadsworth – Thomson Learning Tricarboxylic Acid Cycle TCA or Krebs cycle Cycle –intermediates change from one form to another Converts Pyruvate to –CO 2 –Reducing power NADH FADH 2 used in electron transport for additional ATP synthesis –ATP Figure 5.10

12. © 2004 Wadsworth – Thomson Learning Pentose Phosphate Pathway Production of necessary precursors –Ribose-5-phosphate –Erythrose-4-phosphate Production of electron carriers –NADPH Figure 5.11

13. © 2004 Wadsworth – Thomson Learning Chemiosmosis Electron transport chain Generating a Proton gradient –protons pumped across membrane –occurs as electrons are transported from one carrier to another –high concentration outside of membrane Figure 5.8

14. © 2004 Wadsworth – Thomson Learning Chemiosmosis Generating ATP –Gradient drives ATPase synthesis of ATP from ADP and phosphates –Electron acceptor drives electron transport Oxygen (aerobic respiration) Sulfates, Nitrate, Fumarate (anaerobic respiration) Figure 5.8

15. © 2004 Wadsworth – Thomson Learning Biosynthesis Construct small molecules –Building blocks for macromolecules Uses products of catabolism –Precursor metabolites –ATP –Reducing power Figure 5.12

16. © 2004 Wadsworth – Thomson Learning Polymerization and Assembly Formation of macromolecules –DNA –RNA –Proteins –Polysaccharides –Peptidoglycan Assembly of cellular structure –Self-assembly— spontaneous –Enzyme-catalyzed Figure 5.13

17. © 2004 Wadsworth – Thomson Learning Anaerobic metabolism Anaerobic respiration –Electron transport –Final electron acceptor other than oxygen Fermentation –Substrate-level phosphorylation

18. © 2004 Wadsworth – Thomson Learning Fermentation No chemiosmosis Energy from glycolysis Conversion of pyruvate to other product –lactic acid –ethanol –mixed acids Figure 5.14

19. © 2004 Wadsworth – Thomson Learning Classification by nutrition Heterotrophs –Definition: Different feeders –Organic compounds as source of carbon Autotrophs –Definition: self-feeders –CO 2 as source of carbon Chemotrophs –Definition: chemical feeders –Energy and reducing power from chemical reactions Phototrophs –Definition: light feeders –Energy and reducing power from light energy

20. © 2004 Wadsworth – Thomson Learning Photosynthesis Synthesis of precursor metabolites From CO 2 Calvin-Benson Cycle Figure 5.15

21. © 2004 Wadsworth – Thomson Learning Photosynthesis Anoxygenic photosynthesis –Cyclic photophosphorylation –light energy activates electron –electron transport chain- proton gradient –produces ATP Figure 5.16

22. © 2004 Wadsworth – Thomson Learning Photosynthesis Oxygenic photosynthesis –Noncyclic –two levels of electron activation by light –water is source of electron –results in O 2 production Figure 5.17

23. © 2004 Wadsworth – Thomson Learning Regulation of metabolism Purpose –Ensure optimal amount of end products –Increase cell’s efficiency Types of Metabolic regulation –Enzyme regulation Gene regulation Activity regulation –allosteric activation –feedback inhibition

24. © 2004 Wadsworth – Thomson Learning Enzyme regulation Allosteric activation –product binds enzyme at allosteric site –inactivates enzyme Figure 5.18 Figure 5.20

25. © 2004 Wadsworth – Thomson Learning Enzyme regulation Feedback inhibition –multiple steps in metabolic pathway –end product inhibits enzyme earlier in pathway Figure 5.17