BIOL 210 Bacterial metabolism F22

Page 1: Microbial Metabolism

  • Key Components:

    • Outer Membrane

    • Inner Membrane

    • Electron Transport Chain (ETC) Elements:

      • NADH

      • O2 (Oxygen)

      • H2O (Water)

  • Processes:

    • ATP Synthesis via ATP Synthase

    • Citric Acid Cycle details (sucrose, fumarate)

    • Proton gradients and energy transfer

Page 2: Objectives

  • Differentiate between anabolism and catabolism.

  • Identify components of enzymes and describe enzymatic action.

  • Factors influencing enzymatic activity.

  • Explain oxidation-reduction (redox) reactions.

  • Describe glycolysis and Krebs cycle products.

  • Chemiosmotic model for ATP generation.

  • Compare aerobic and anaerobic respiration.

  • Chemical reactions and products of fermentation.

  • Categorize organism nutritional patterns according to energy and carbon source.

Page 3: Metabolism Overview

  • Metabolism: Sum of all chemical reactions in an organism.

  • Catabolism: Energy-releasing reactions that provide building blocks for anabolism.

  • Anabolism: Energy-consuming reactions that synthesize large molecules.

  • Metabolic Pathways: Sequence of enzymatically catalyzed reactions encoded by genes.

Page 4: Role of ATP

  • ATP Function:

    • Transfers energy from catabolic to anabolic reactions.

    • Converts ADP + Pi to ATP.

    • Generates heat during energy transfer.

Page 5: Collision Theory

  • States that reactions occur when particles collide.

  • Activation Energy: Minimum energy required to initiate a reaction.

  • Reaction Rate: Influenced by collision frequency, temperature, pressure, and enzyme activity.

Page 6: Enzyme Activation

  • Enzymatic Mechanisms:

    • Enzymes lower activation energy for reactions.

    • Reaction progress visualized in enzyme vs. no enzyme scenarios.

  • End products: Glucose and Fructose from sucrose.

Page 7: Enzymes

  • Characteristics:

    • Biological catalysts that are specific and not consumed in reactions.

  • Components:

    • Apoenzymes, Cofactors, Holoenzymes, Coenzymes (e.g., NAD+).

  • Naming examples: Lactate dehydrogenase, Cytochrome oxidase.

Page 8: Enzymatic Reactions

  • Mechanism: Active site binds substrate, forming an enzyme-substrate complex.

  • Reaction alters the substrate slightly and products are glucose and fructose.

  • Enzyme remains unchanged.

Page 9: Factors Influencing Enzyme Activity

  • Denaturation: Loss of enzyme function from denaturation.

  • Substrate Concentration: Affects rate of reaction.

Page 10: Enzyme Inhibitors

  • Types of Inhibitors:

    • Competitive Inhibitors

    • Noncompetitive (Allosteric) Inhibitors.

Page 11: Sulfa Drugs

  • Chemistry:

    • Example: Sulfanilamide mimics PABA, a substrate for bacterial enzymes.

Page 12: Feedback Inhibition

  • Definition: Control mechanism preventing overproduction of substances.

  • Non-competitive action by end-products.

Page 13: Redox Reactions

  • Oxidation: Removal of electrons.

  • Reduction: Gain of electrons.

  • Biological oxidations include dehydrogenation reactions.

Page 14: Biological Redox Reactions

  • Electrons often linked with hydrogen atoms.

  • Reduced compounds gain protons, transporting electrons.

Page 15: ATP Generation

  • Phosphorylation Types:

    • Substrate-level phosphorylation.

    • Oxidative phosphorylation via ETC and chemiosmosis.

Page 16: Energy Production Pathways

  • Cellular Respiration Types:

    • Aerobic: Complete oxidation of substrates.

    • Anaerobic: Partial oxidation with less ATP yield.

    • Fermentation: Anaerobic breakdown of organic molecules.

Page 17: Glycolysis Steps

  • Glucose converts to pyruvate.

  • ADP + Pi generates ATP.

  • NAD+ is converted to NADH.

Page 18: Krebs Cycle

  • Generates acetyl-CoA from pyruvate (decarboxylation).

  • Produces ATP, reducing power, and precursor metabolites.

Page 19: Detailed Krebs Cycle

  • Cycling of compounds through decarboxylation and oxidation steps.

  • Key produce: 2 CO2, NADH, FADH2, ATP.

Page 20: Electron Transport Chain

  • Series of electron carriers that facilitate redox reactions.

  • Generates proton gradient for ATP synthesis through chemiosmosis.

Page 21: Chemiosmotic ATP Generation

  • Proton motive force drives ATP production.

  • NADH and O2 involvement in the process.

Page 22: Respiration vs. Fermentation

  • Respiration:

    • Pyruvic acid enters Krebs cycle, producing CO2 and energy carriers (NADH, FADH2).

    • ATP produced via electron transport.

  • Fermentation: Uses pyruvic acid with lower energy yields; end products depend on the fermenting organism.

Page 23: Anaerobic Respiration

  • Uses inorganic molecules as final electron acceptors (e.g., NO3-, SO4-).

  • Lower ATP yield compared to aerobic respiration.

Page 24: Fermentation Overview

  • General definitions (spoilage, alcohol, microbial processes).

  • Scientific definition: Organic molecules as final electron acceptors without Krebs or ETC, yielding low energy.

Page 25: Fermentation Pathways

  • Glycolysis: Generates NADH and ATP.

  • In Lactate fermentation, pyruvate converts to lactate regenerating NAD+.

  • In Alcohol fermentation, pyruvate converts to acetaldehyde then ethanol.

Page 26: Polysaccharide Catabolism

  • Enzymes for digestion of polysaccharides: Amylases and Cellulases (specific to bacteria and fungi).

Page 27: Lipid Catabolism

  • Lipids broken down by lipases into glycerol and fatty acids.

  • Fat metabolism links to both glycolysis and Krebs cycle.

Page 28: Protein Catabolism

  • Processes:

    • Extracellular proteases break down proteins, leading to deamination and other reactions yielding organic acids.

Page 29: Protein Pathways

  • Metabolites formed from various amino acids enter the Krebs cycle or used for gluconeogenesis.