Cultivation of Bacteria Flashcards
what effects bacterial growth?
nutritional factors
environmental factors
what are abiotic environmental factors that affect bacterial growth?
temperature, pH, oxygen, CO, water availability/osmotic pressure
what are most bacteria - pick on the chart
mesophiles
what is the transport media and cultures media usual pH? why is this important
7 - has buffers to keep at this value
optimal pH for most bacteria 6.5-7.5
label the aerobic capacity of the bacteria? ex. obligate aerobe, obligate anerobe
what do anerobic bacteria require to grow?
anaerobic transport media
reducing culture media
anaerobic jar
what is a capnophile?
bacteria requiring 5-10% CO2 for optimal growth
what are most capnopiles aerobic descriptor?
microerophilic
what type of bacteria do not require NaCl but can grow under saline?
Halotolerant bacteria
how does transport media help prevent desiccation?
provide moisture until sample can be cultured
what is a chemoheterotroph?
use organic compounds for energy and carbon
what is a fastidious bacteria?
requiring additional organic compounds in their culture media
Are most bacteria chemoheterotrophic or fastidious?
chemoheterotrophic
which require more growth factors - chemoheterotrophic or fastidious?
fastidious
match the term to the description - liquid media, solid media, semi-solid agars
- used for isolation of pure cultures, estimating the number of viable bacteria
- ideal for growing large numbers of bacteria
- used for determining motility, growing microaerophiles
1 - solid media
2 - liquid media
3 - semi-solid agars
what are growth factors
things that bacteria need for growth and the organism cannot synthesize
Is agar a solidifying agent or nutrient?
solidifying agent
what is a colony?
population of cells arising from a single cell or spore, or from a group of cells of the same species or strain
what is the function of basal media?
sustain growth of less fastidious bacteria
what is the function of enriched media?
basal media + additional nutrients, used to cultivate fastidious organisms
what is the function of selective media?
reagents added that inhibit the growth of unwanted bacteria while allowing the growth of others
what is the function of differential (indicator) media?
contain components that allow the differentiation of closely related taxa based on appearance of colony or surrounding media
what is the function of transport media?
for transport of clinical specimens to the lab, preserve microbial viability and help maintain the original ratio of microbes in the sample
what is a pure culture?
contains only 1 species of microbe
what are the goals of a preserved pure culture?
viability, purity, and genetic stability
how can you preserve bacterial cultures?
subculture of growing cells, snap-freeze cells in broth w/ cryopreservative, freeze-dry cells suspended in lyophilization media
how do bacteria grow? (mitosis, meiosis, binary fission, etc.)
binary fission
what is generation time?
time required for population to double
Label the growth phases
describe lag phase
no cell division, preparing for growth
describe log (exponential) phase
exponential growth
describe stationary phase
zero population growth
describe death/decline phase
exponential death
After decline phase what can some viable bacteria enter?
long-term stationary phase
define colony
population arising from a single cell or spore, or from a group of cells of the same species or strain
what is the difference between a batch culture and continuous culture?
batch culture - grow in closed system, exponential growth cannot be maintained
continuous culture - growth in chemostat, fresh medium continuously added, exponential growth can be maintained
