Characteristics of Prokaryotes

Study Notes

Bacteria:
- Gram-positive (thick peptidoglycan layer, e.g., Staphylococcus)
- Gram-negative (thin peptidoglycan layer, e.g., E. coli)
Archaea:
- Methanogens (produce methane gas)
- Thermophiles (thriving in high temperatures)
- Halophiles (thriving in high salt concentrations)

Protists:
- Protozoa (e.g., Amoeba, Paramecium)
- Algae (e.g., seaweed)
Fungi:
- Molds (e.g., Aspergillus)
- Yeasts (e.g., Saccharomyces)
Plants:
- Bryophytes (e.g., mosses)
- Vascular plants (e.g., trees)
Animals:
- Invertebrates (e.g., insects, worms)
- Vertebrates (e.g., humans, fish)

Symbiotic relationships:
- Mutualism (e.g., gut bacteria and host)
- Commensalism (e.g., bacteria on skin)
- Parasitism (e.g., pathogenic bacteria)
Microbial communication:
- Quorum sensing (cell-density dependent gene regulation)
- Biofilm formation (complex microbial communities)

Lack a true nucleus and membrane-bound organelles, making them simple in structure
Typically small in size, ranging from 0.5-5.0 μm
Cell wall is composed of peptidoglycan (also known as murein)
Often have a single circular chromosome
Reproduce by binary fission
Examples of prokaryotes include Bacteria (e.g., E.coli) and Archaea (e.g., methanogens)

Bacteria:
- Gram-positive bacteria have a thick peptidoglycan layer (e.g., Staphylococcus)
- Gram-negative bacteria have a thin peptidoglycan layer (e.g., E.coli)
Archaea:
- Methanogens produce methane gas
- Thermophiles thrive in high temperatures
- Halophiles thrive in high salt concentrations

Possess a true nucleus and membrane-bound organelles, making them more complex in structure
Typically larger in size, ranging from 5-100 μm
Have linear chromosomes with histone proteins
Reproduce by mitosis
Examples of eukaryotes include protozoa, fungi, plants, and animals

Protists:
- Protozoa (e.g., Amoeba, Paramecium)
- Algae (e.g., seaweed)
Fungi:
- Molds (e.g., Aspergillus)
- Yeasts (e.g., Saccharomyces)
Plants:
- Bryophytes (e.g., mosses)
- Vascular plants (e.g., trees)
Animals:
- Invertebrates (e.g., insects, worms)
- Vertebrates (e.g., humans, fish)

Microorganisms can be found in various habitats, including:
- Soil microbiome
- Aquatic environments (e.g., oceans, lakes, rivers)
- Human microbiome (gut, skin, respiratory tract)
- Extreme environments (e.g., hot springs, deep-sea vents)
Microorganisms interact with each other and their environment through:
- Symbiotic relationships, including mutualism, commensalism, and parasitism
- Microbial communication, including quorum sensing and biofilm formation