Microbiology midterm II

Introductory Microbiology Overview

  • Course Title: Introductory Microbiology (BIOL 228)

  • Instructor: Nusrat J. Urmi

  • Department: Biology Dept.

  • Year: 2016

  • Publisher: Pearson Education, Inc.

Microbial Metabolism

Key Concepts

  1. Metabolism Fundamentals

    • Metabolism: Sum of all biochemical reactions (anabolism + catabolism).

    • Anabolism: Energy-requiring processes (e.g., synthesis of chemical compounds).

    • Catabolism: Breakdown of compounds to release energy.

  2. Metabolic Classes of Microorganisms

    • Phototrophs: Obtain energy from light (oxygenic and anoxygenic photosynthesis).

    • Chemotrophs: Obtain energy from chemical reactions (aerobic/anaerobic respiration).

      • Chemoorganotrophs: Use organic compounds for energy.

      • Chemolithotrophs: Use inorganic compounds for energy.

    • Heterotrophs: Obtain carbon from organic sources.

    • Autotrophs: Obtain carbon from CO2 (primary producers).

Energy and Electron Transfer

  • Redox Reactions: Involves electron donors and acceptors.

  • NAD+/NADH: Key electron carriers facilitating redox reactions; recycled during metabolic processes.

  • ATP Production: Energy-rich compounds involved in ATP synthesis through oxidation-reduction reactions.

Catabolic Processes

  • Two Pathways: Fermentation and respiration differ in ATP synthesis mechanisms.

    • Fermentation: Substrate-level phosphorylation (ATP directly from an energy-rich intermediate).

    • Respiration: Oxidative phosphorylation, utilizing proton motive force (PMF).

  • Glycolysis: Common catabolic pathway for glucose, producing ATP and fermentation products.

Citric Acid Cycle (CAC)

  • Pathway oxidizing pyruvate to CO2, generating NADH and FADH.

  • CAC is pivotal for catabolism and biosynthesis.

  • Higher ATP yield in aerobic respiration (38 ATP in prokaryotes, 36 in eukaryotes).

Electron Transport Chain

  • Electron carriers mediate electron transfer, facilitating ATP synthase to produce ATP from PMF.

  • Complexes I-IV: Involved in transporting electrons and forming PMF.

Biosynthesis

Sugars and Polysaccharides

  • Synthesis from activated glucose (e.g., ADPG for glycogen).

  • Gluconeogenesis allows glucose synthesis from intermediates.

Amino Acids and Nucleotides

  • Biosynthesis involves multistep pathways originating from glycolysis or the citric acid cycle.

  • Purine and Pyrimidine: Complex pathways for nucleotides biosynthesis.

Fatty Acids and Lipids

  • Fatty acids are synthesized two carbons at a time, with acyl carrier protein (ACP) involvement.

Photosynthesis Overview

  • Autotrophic Pathways: CO2 is assimilated into organic material via pathways like the Calvin cycle.

    • Calvin Cycle: Requires ATP and NADPH; key enzyme is RubisCO.

    • Reverse Citric Acid Cycle: Used by certain bacteria for CO2 fixation.

Photosystems

  • Oxygenic photosynthesis generates ATP and NADPH through two light reactions.

  • Chlorophylls: Pigments neccessary for phototrophy.

Viral Overview

Definitions

  • Virus: Obligate intracellular parasite with a nucleic acid genome.

  • Virion: Extracellular form facilitating transmission.

Viral Replication Cycle

  1. Attachment

  2. Penetration

  3. Synthesis of nucleic acid and proteins

  4. Assembly and release of new virions.

Immunology Basics

Immunity Types

  • Innate Immunity: Nonspecific, rapid response to pathogens.

  • Adaptive Immunity: Specific response requiring previous exposure to the pathogen.

Immune Response

  • Phagocytes: Recruit to infection sites and engulf pathogens.

  • Inflammation: Localized response; helps isolate infection and recruit immune cells.