1. Introduction

Microbiology is the scientific study of microscopic organisms, including bacteria, viruses, fungi, protozoa, and archaea. These organisms are fundamental to ecosystems, human health, industry, and biotechnology.

2. Major Groups of Microorganisms

Microorganism Description Example
Bacteria Single-celled, prokaryotic, diverse metabolism Escherichia coli
Viruses Non-living, require host to replicate Influenza virus
Fungi Eukaryotic, includes yeast and molds Saccharomyces cerevisiae
Protozoa Unicellular, eukaryotic, motile Amoeba proteus
Archaea Prokaryotic, extremophiles Halobacterium

3. Cell Structure & Function

Prokaryotic vs. Eukaryotic Cells

Cell Structure Diagram

  • Prokaryotes: No nucleus, circular DNA, simple organelles.
  • Eukaryotes: Nucleus, linear DNA, complex organelles.

Key Structures

  • Cell wall: Protection and shape.
  • Plasma membrane: Controls entry/exit.
  • Flagella/cilia: Movement.
  • Ribosomes: Protein synthesis.

4. Microbial Growth & Reproduction

  • Binary fission: Most bacteria reproduce by splitting into two.
  • Budding: Yeast and some bacteria.
  • Viral replication: Hijacking host machinery.

Growth Curve Phases

  1. Lag phase
  2. Log (exponential) phase
  3. Stationary phase
  4. Death phase

5. Environmental Microbiology

Microbes are found in every habitat, from soil to water, air, and extreme environments (hot springs, deep sea).

Plastic Pollution in Deep Oceans

Recent discoveries show microplastics in the Mariana Trench, the deepest ocean point. Microbes interact with plastics, sometimes colonizing and degrading them.

Reference:
Peng, X., et al. (2020). “Microplastics in the deepest ocean: The Mariana Trench.” Science of The Total Environment, 698, 134123. Link

6. Microbes & Human Health

  • Pathogens: Cause diseases (e.g., tuberculosis, COVID-19).
  • Normal flora: Beneficial, aid digestion, immunity.
  • Antibiotics: Target bacteria, not viruses.

7. Industrial & Biotechnological Applications

  • Fermentation: Bread, yogurt, beer.
  • Bioremediation: Cleaning oil spills, degrading plastics.
  • Genetic engineering: Insulin production, vaccines.

8. Surprising Facts

  1. Plastic-eating bacteria have been isolated from polluted environments, showing potential for bioremediation.
  2. Microbes outnumber human cells in the body; the human microbiome is essential for health.
  3. Viruses infect bacteria (bacteriophages) and are used in phage therapy against antibiotic-resistant infections.

9. Controversies in Microbiology

  • Antibiotic resistance: Overuse in medicine and agriculture leads to “superbugs.”
  • Genetically modified organisms (GMOs): Safety and ecological impact debated.
  • Plastic biodegradation: Are plastic-eating microbes a solution or risk for ecosystems?

10. Mnemonic for Major Microbe Groups

“B Very Fast People Are Micro”

  • Bacteria
  • Viruses
  • Fungi
  • Protozoa
  • Archaea
  • Microalgae

11. Teaching Microbiology in Schools

  • Theory: Textbooks, diagrams, case studies.
  • Lab work: Microscopy, culturing bacteria, observing yeast fermentation.
  • Digital tools: Simulations, virtual labs, interactive quizzes.
  • Field studies: Sampling soil/water, observing microbial colonies.

12. Recent Research Highlight

A 2020 study reported microplastics in the Mariana Trench, with microbial communities colonizing these plastics. This suggests microbes may adapt to pollutants, but the ecological consequences are unknown.
Peng, X., et al. (2020). “Microplastics in the deepest ocean: The Mariana Trench.” Science of The Total Environment.

13. Summary Table

Topic Key Points
Groups of Microbes Bacteria, Viruses, Fungi, Protozoa, Archaea
Cell Structure Prokaryotic vs. Eukaryotic
Growth Binary fission, budding, viral replication
Human Health Pathogens, normal flora, antibiotics
Environment Ubiquity, plastic pollution, extremophiles
Applications Fermentation, bioremediation, GMOs
Controversies Resistance, GMOs, biodegradation risks

14. Diagrams

15. Further Reading

  • Peng, X., et al. (2020). “Microplastics in the deepest ocean: The Mariana Trench.” Science of The Total Environment, 698, 134123.
  • “Microbiology: An Evolving Science” (Textbook)
  • Microbiology Society

End of Notes