Microbial Metabolism, Glycolysis, TCA Cycle

Metabolic Pathways in Microorganism

1. Chapter 5 Microbial Metabolism

2. What is Metabolism? Metabolism is the buildup and breakdown of nutrients within a cell. These chemical reactions provide energy and create substances that sustain life. Involves two key players Enzymes ATP

3. Enzymes Generally Proteins Requires Cofactors or coenzymes (FAD, NAD+ & NADPH) Binds to specific substrate (only)  Product For Example- ELISA

4. ATP (Adenosine triphosphate) A molecule that stored excess energy in the form of phosphate bonds When need some phosphate bond is break and energy released

5. Metabolic Pathways

6. Catabolism Anabolism Breakdown of complex carbs Building of complex carbs Degradative and hydrolytic reaction Biosynthesis and dehydration synthesis process Exergonic (produce more energy, consumes less energy) Endergonic (produce less energy, consumes more energy) Glucose  CO2 + H2O Formation proteins, nucleotides etc.

7. Energy Links Pathways Both pathways are linked by energy. Catabolism provide energy for anabolism.

8. Structure of ATP One nitrogenous base (adenine), a five-carbon sugar (ribose), and three phosphate groups. High energy stored in triphosphate bonds, released when a phosphate group is broken off and converts ATP into adenosine diphosphate (ADP).

9. Enzymes Biological catalysts that speed up reactions without being consumed. It always acts upon its specific substance called substrate via active site. Lock & Key Induced Model

10. Substrate contacts with enzymes active site Form enzyme substrate complex Substrate convert into products Enzyme is recovered and unchanged Mechanism Of Enzymatic Actions

11. Characteristics of Enzymes • Specificity - Specific to substrate • Efficiency - highly efficient under optimal conditions • Reusability & Turnover number- Max no. of substrate an enzymes convert (1 or 10,000 or 500,000) Example- DNA polymerase I, turnover no. is 15. Lactate dehydrogenase, removes H+ from lactic acid, turnover no. is 1000.

12. Enzyme Components Apoenzymes- inactive protein which requires non protein component to activate called Cofactor- a non protein component that bind to apoenzymes and make an active enzymes called Holoenzymes- An activated enzymes ready to bind with substrate

13. Enzyme Naming ( - ase ) Class Functions Example Hydrolase Hydrolysis or addition of water Lipase Ligase Joining of two molecules DNA Ligase Oxidoreductase Oxidation reduction reactions Cytochrome oxidase Transferase Transfer of functional group Kinases Lyase Removal of atom with hydrolysis Isocitrate layse

14. Factors Affecting Enzymes The optimal activity of enzymes influence by Temperature - 35C to 37C pH -5.0 Substrate concentration - Increase substrate α Increase reactions

15. Enzyme Inhibition A way to control growth of bacteria by inhibit, their enzymes. Antibiotics and heavy metals (arsenic & mercury). As a result, the cells stop functioning and die.

16. Glycolysis vs. Fermentation Glycolysis Fermentation Complete breakdown of glucose into pyruvic acid Incomplete breakdown glucose into alcohol (in prokaryotes) and lactic acid (in eukaryotes) Inside the cytoplasm Outside of the cell Completed in 9 steps Completed in 2 steps 2NADPH and 2 ATP molecules released None No CO2 release CO2 release during alcohol fermentations Aerobic respirations Anaerobic respiration

17. Glycolysis Also called Embden-Meyerhof pathway . Glycolysis means splitting sugar by releasing energy Composed of 9 steps and 2 stages Preparatory stage Energy conserving stage

18. Krebs Cycle Pyruvic acid is converted into Krebs cycle, acetyl CoA. Produce ATP and CO2 Electron carriers NAD+ and FAD. Donate electrons to the electron transport chain.

19. Electron Transport Chain A system take place in mitochondria, where a series of electrons pass along the chain in a gradual and stepwise process.

20. Fermentation

21. ATP Yield Comparison Aerobic respiration: 38 ATP Fermentation: 2 ATP

22. Applications of Microbial Metabolism • Fermentation: beer, wine, yogurt • Biotechnology: antibiotics, enzymes • Environment: sewage treatment, nutrient cycling