Chapter 7&8 Lec Notes

Microbial Metabolism Overview

• Metabolism: Sum of all chemical reactions in a cell

Key Components of Metabolism

• Anabolism: Synthesis reactions (require energy)

  • Example: Use of anabolic steroids to build muscles

  • Function: Builds complex molecules

• Catabolism: Breakdown reactions (release energy)

  • Example: A cat breaking a vase, symbolizing destructive actions

Enzymes

• Enzymes: Biological catalysts speeding up reactions

  • Made of specialized proteins

  • Require co-factors and coenzymes to function

• Cofactors and Coenzymes:

  • Cofactors: Inorganic minerals

  • Coenzymes: Organic vitamins

  • Together, they form Haloenzymes

• Enzyme Function:

  • Substrate binds to the active site, forming an ES complex (lock and key model)

• Types of Enzymes:

  • Constitutive Enzymes: Constantly produced

  • Regulated Enzymes: Production varies based on needs

Environmental Influences on Enzyme Activity

• Optimal conditions: Temperature, pH, osmotic pressure essential

• Heat and extreme pH can denature proteins and hinder function

Metabolic Pathways

• Begin with a specific molecule and end with a product

• Series of reactions catalyzed by different enzymes

Controls on Enzyme Action

• Inhibitors:

  • Competitive Inhibitors: Mimic substrates and compete for the active site

  • Noncompetitive Inhibitors: Bind to regulatory sites and cause changes in enzyme activity

Energy in Cells

• Exergonic Reactions: Release energy

• Endergonic Reactions: Require energy to proceed

Oxidation-Reduction (Redox Reactions)

• Involve transfer of electrons

• Key players: NAD and FAD as electron carriers

Genetic Concepts

• Genotype: Genetic makeup

• Phenotype: Observable traits

• Chromosomes: Genetic material organized in structures

Transcription and Translation Overview

• Transcription: DNA to RNA process

  • RNA Polymerase initiates transcription at promoter sites

• Translation: RNA to protein process using mRNA, tRNA, and ribosomes

• Codons signify amino acids, with redundancy in the genetic code

• Operon: Genes regulated as a unit, controlling metabolic pathways based on nutrients availability

• Phase Variation: Ability of bacteria to turn gene families on/off to adapt to environmental changes, enhancing pathogenicity.