Microbial Physiology Overview

Microbial Physiology

• Definition: Study of the functions and processes of microorganisms at cellular and molecular levels.

• Cell Structure:

  • Prokaryotes vs. Eukaryotes:
    • Prokaryotes: No nucleus, smaller, simpler (bacteria and archaea).
    • Eukaryotes: Nucleus present, larger, more complex (fungi, protozoa).
  • Cell Wall: Provides shape and protection; composed of peptidoglycan in bacteria.

• Metabolism:

  • Catabolism: Breakdown of organic matter to release energy.
    • Example: Glycolysis, Krebs cycle, fermentation.
  • Anabolism: Synthesis of cellular components using energy.
    • Example: Protein synthesis, nucleic acid formation.

• Energy Sources:

  • Autotrophs: Use CO2 as a carbon source (e.g., photosynthetic bacteria).
  • Heterotrophs: Require organic compounds for carbon (e.g., most bacteria, fungi).
  • Chemolithotrophs: Obtain energy from inorganic compounds.

• Growth and Reproduction:

  • Binary Fission: Asexual reproduction method in bacteria.
  • Growth Curve: Phases include lag, log (exponential), stationary, and death phases.
  • Doubling Time: Time taken for the population to double; varies by species and conditions.

• Nutritional Requirements:

  • Macronutrients: Required in large amounts (e.g., carbohydrates, proteins, lipids).
  • Micronutrients: Required in trace amounts (e.g., vitamins, minerals).
  • Growth Factors: Organic compounds needed for growth (e.g., amino acids, nucleotides).

• Environmental Factors:

  • Temperature: Affects enzyme activity and growth rate; categorized as psychrophiles, mesophiles, thermophiles.
  • pH: Most bacteria prefer neutral pH; extremophiles can thrive in acidic or alkaline conditions.
  • Oxygen Requirements:
    • Aerobes: Require oxygen.
    • Anaerobes: Do not require oxygen; some are harmed by it (obligate anaerobes).
    • Facultative anaerobes: Can grow with or without oxygen.

• Signaling and Communication:

  • Quorum Sensing: Bacteria communicate and coordinate behavior based on population density.
  • Biofilms: Structured communities of microorganisms adhering to surfaces; exhibit cooperative behaviors.

• Adaptation and Resistance:

  • Antibiotic Resistance: Mechanisms include enzyme production, altered target sites, and efflux pumps.
  • Stress Responses: Mechanisms to survive adverse conditions (e.g., heat shock proteins, spore formation).

• Applications:

  • Biotechnology: Use of microbes for industrial processes (e.g., fermentation, bioremediation).
  • Medicine: Understanding pathogenic mechanisms for disease treatment and prevention.

Microbial Physiology

• Focuses on the functions and processes of microorganisms at cellular and molecular levels.

Cell Structure

• Prokaryotes:
  • Lack a nucleus, are smaller and simpler; includes bacteria and archaea.
• Eukaryotes:
  • Have a nucleus, larger and more complex; includes fungi and protozoa.
• Cell Wall:
  • Offers shape and protection; composed of peptidoglycan in bacteria.

Metabolism

• Catabolism:
  • Involves the breakdown of organic matter to release energy through processes like glycolysis, Krebs cycle, and fermentation.
• Anabolism:
  • Involves the synthesis of cellular components using energy; examples include protein synthesis and nucleic acid formation.

Energy Sources

• Autotrophs:
  • Utilize CO2 as a carbon source, commonly seen in photosynthetic bacteria.
• Heterotrophs:
  • Require organic compounds for carbon; includes most bacteria and fungi.
• Chemolithotrophs:
  • Derive energy from inorganic compounds.

Growth and Reproduction

• Binary Fission:
  • Asexual reproduction method for bacteria.
• Growth Curve:
  • Consists of four phases: lag, log (exponential), stationary, and death.
• Doubling Time:
  • The duration needed for population to double; varies among species and environmental conditions.

Nutritional Requirements

• Macronutrients:
  • Needed in large quantities; includes carbohydrates, proteins, and lipids.
• Micronutrients:
  • Required in trace amounts; includes vitamins and minerals.
• Growth Factors:
  • Essential organic compounds for growth; examples include amino acids and nucleotides.

Environmental Factors

• Temperature:
  • Influences enzyme activity and growth rate; classified as psychrophiles (cold-loving), mesophiles (moderate), and thermophiles (heat-loving).
• pH:
  • Most bacteria thrive at neutral pH; some extremophiles adapt to acidic or alkaline environments.
• Oxygen Requirements:
  • Aerobes require oxygen, non-aerobic anaerobes do not (some are harmed by oxygen), and facultative anaerobes can grow in both conditions.

Signaling and Communication

• Quorum Sensing:
  • Mechanism where bacteria communicate and coordinate behavior based on their population density.
• Biofilms:
  • Structured microbial communities that adhere to surfaces and display cooperative behaviors.

Adaptation and Resistance

• Antibiotic Resistance:
  • Mechanisms include production of enzymes, alteration of target sites, and utilization of efflux pumps.
• Stress Responses:
  • Adaptive mechanisms for survival during adverse conditions, such as heat shock proteins and spore formation.

Applications

• Biotechnology:
  • Involves using microbes for various industrial processes such as fermentation and bioremediation.
• Medicine:
  • Understanding pathogenic mechanisms aids in disease treatment and prevention.

Explore the fascinating world of microbial physiology, focusing on the cellular and molecular functions of microorganisms. This quiz covers key concepts such as cell structure differences between prokaryotes and eukaryotes, metabolic processes, and energy sources utilized by microorganisms.