Chapter 41 intro to microbiology

prokaryotic

• has no nuclear membrane

• most cellular organelles are absent, except cell walls, plasma membranes, and ribosomes

• some may contain capsules and flagella and can develop endospores

• very small 0.2-2.0 micrometers

obligate aerobes

• require O2 to survive

obligate anaerobes

• growth inhibited or killed by presence of O2

Facultative anaerobes

• can survive O2 but growth is limited

microaerophilic

• prefer reduced O2 tension

Capnophilic

• require high levels of carbon dioxide

Endospores

• resistant to heat, desiccation, chemicals, and radiation

4 phases of bacterial growth

• initial - adapting to new media

• exponential - rapid growth until there is no more space, waste accumulates or nutrients are used up

• stationary - no net increase or decrease

• final - death, spore formation occurs

heterotrophs characteristics

• parasitic or saprophytic (decomposers)

• most multicellular - except yeast

• Eukaryotic cells with cell walls of chitin

• large webs (mycelium) of slender tubes (hyphae)

• digest food internally - enzymes

• yeast reproduce by budding