Bio 144

Microbial Diversity

Types of Microscopes

Light & Electron microscope

Transmission electron microscope

Used to view internal structures of cells at very high magnification by transmitting electrons through a thin specimen.

Scanning electron microscope

Used to study the surface of objects by scanning them with a focused beam of electrons, producing high-resolution three-dimensional images.

Characteristics of microbes

1) Found all over (ubiquitous)

2) Aerobic/anaerobic

3) Nutrient cycling

4) Less complex

5) Horizontal gene transfer

6) Diverse metabolic pathways - rapid growth rate

7) Co-evolved

Importance of microbes

1) Created prehistoric atmosphere

2) Nitrogen fixing

3) Decomposition

3 Domains

Bacteria, Archaea, Eukarya

Differences between 3 Domains

First person to observe microorganisms

Antonie van Leeuwenhoek

Protists

Uni/multicellular

Asexual/sexual reproduction

Fungi

Chemoheterotrophic, multicellular decomposers

Plantae

Multicellular photoautotrophs

Rigid cell walls

Anamalia

Multicellular chemoheterotrophic

Cell walls

Bacteria characteristics

No membrane-bound organelles

Prokaryotes

Small

Rapid production

Archaea characteristics

Extreme habitats

Gene translation machinery → Eukarya

Prokaryotes vs Eukaryotes

Taxonomic domain associated with methanogenesis

Archaea

Basic taxon of classification systems

Species

Kingdom that Saccharomyces cerevisiae belongs to

Fungi

DNA-associated feature that only occurs in Eukarya

Nucleus

Differences between Bacteria & Eukarya that make it possible to target drugs against bacteria alone

Cell Wall Composition: Bacteria have a rigid cell wall made of peptidoglycan, while eukaryotic cells lack such a structure

Nucleus: Eukaryotic cells have a membrane-bound nucleus, whereas bacteria have a nucleoid region with circular DNA

Ribosomes: Bacterial ribosomes are smaller compared to eukaryotic ribosomes

Metabolic Pathways: Bacteria have unique metabolic pathways that eukaryotic cells do not