Lecture Notes: Introduction to Microbiology - Chapter 1, Section 1.3

Overview

• Instructor: Dr. Hinke
• Focus: Introduction to types of microorganisms and acellular infectious agents.
• Objectives:
  • List types of microorganisms and acellular agents.
  • Describe similarities and differences between archaea and bacteria.
  • Provide examples of cellular and viral microorganisms and infectious agents.
  • Overview of different areas in microbiology.

Microorganisms Overview

• Definition: Microbes are not visible to the naked eye; typically visible under 100 micrometers.
• Scale: Microorganisms are smaller than 100 micrometers.
  • Examples: Red blood cells (10 micrometers), Mitochondria, Viruses.
• Components of Viruses: Made of nucleic acid and protein.

Living Things

• Microscopic Organisms: Include both prokaryotic and eukaryotic cells.
• Prokaryotes:
  • Bacteria: Smaller than eukaryotic cells, majority are beneficial.
  • Archaea: Similar to bacteria in size but distinct molecularly, found in extreme environments, no known pathogens.
• Eukaryotes:
  • Include protists, fungi, and helminths.

Bacteria and Archaea

• Bacteria: Shape-based classification; includes cocci, bacilli, spirilla.
• Archaea: Lack nucleus, distinct molecular differences, thrive in extreme environments.

Types of Eukaryotic Microorganisms

• Protists:
  • Plant-like (algae), fungus-like (water molds), and animal-like (protozoans).
• Fungi: Yeasts (single-celled) and molds (multicellular).
• Helminths: Multicellular worms, microscopic in egg and larval stages.

Acellular Microorganisms

• Viruses:
  • Obligate intracellular parasites, lack cellular organization.
  • Not classified as living due to lack of metabolism, cellular organization.

Sub-disciplines in Microbiology

• Bacteriology: Study of bacteria.
• Mycology: Study of fungi.
• Protozoology: Study of protozoans.
• Virology: Study of viruses.
• Immunology: Study of immune responses.
• Others: Marine, environmental, agricultural, etc.

Key Points

• Pathogens: Organisms causing disease; most microbes are helpful.
• Bacteria vs Viruses: Bacteria are much larger than viruses.

Review Questions

• Match sub-disciplines with descriptions (e.g., immunology with antibodies).
• Define pathogen as a disease-causing organism.
• Identify mosquitoes as non-microorganisms.
• Remember that many microbes are helpful.

Final Remarks

• Importance of microbiology in healthcare and ecosystem.
• Encouragement to view the microbial world as essential to life.