Chapter 37- Intro to Microbiology Flashcards
prokaryotes have requirements for
Temperature, pH, oxygen tension, and nutrition
Do prokaryotes contain a nucleus?
No
Most clinically significant bacterial species require pH of
6.5-7.5
Obligate aerobes require _ to survive
Oxygen
Obligate anaerobes
growth inhibited or killed in the presence of oxygen
Facultative anaerobes
can survive in oxygen but growth is limited
Microaerophilic
prefer reduced oxygen tension
Capnophilic
require high levels of carbon dioxide
Culture media types are chosen on the basis of
the bacterias nutritional requirments
Fastidious microbes
bacteria that have strict nutritional requirements
Mesophiles
almost all pathogenic bacteria in animals grow best at 20-40 degrees Celsius
psychrophiles
lower temperatures
thermophiles
higher temperatures
coccus
cocci, spherical cells
bacillus
bacilli, shaped like rods or cylinders
Spiral
spirochetes, usually occur single and can be loose spirals, tight spirals, or comma-shaped spirals
Coccobacillus
coccobacilli, some small rod-shaped bacteria stain in a polar fashion that causes them to have the appearance of two cocci in a pair
Pleomorphic
shapes that range from cocci to rods
Arrangements
single, pairs, clusters, chains, palisades
Endospores location can be
central, subterminal, or terminal
Spores are resistant to
heat, desiccation, chemicals, and radiation
Bacteria reproduce primarily by
binary fusion
4 phases of colonization for bacterial growth
1.Initial- “lag phase” adapting to new media
2.Exponential- “doubling time or generation time” rapid growth
3.Stationary- no net increase or decrease in total number of cells
4.Logarithmic decline- “death phase”, spore formation
Fungi are
heterotrophs (an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter)
