Chapter 5 Flashcards
bacterial and archaean cells reproduce asexually via……
binary fission
what ensures proper division during of the bacterial cell cycle
two checkpoints
the interval required to progress through the cell cycle and produce two daughter cells
generation time or doubling time
how many daughter cells are produced at the end of the bacterial cell cycle
two
in pathogens a ________ doubling time means a _______ incubation period of disease
shorter
shorter
bacteria adapt to their new environment; no cell division occurs
lag phase
exponential growth; human disease symptoms usually develop
log phase
reproductive and death rates equalize
stationary phase
accumulation of waste products and scarcity of resources cause the population to die
decline phase
a subset of bacterial cells that maintain a low rate of metabolism
persister cells
persister cells are unaffected by what
antibiotics
when antibiotic is withdrawn from persister cells, these cells can……..
repopulate the colony
are a response to nutrient limitation
endospores
how many genera are endospore forming and what are they
2
bacillus and clostridium
are bacillus and clostridium gram positive or gram negative
gram positive
what is an example of a diseases caused by bacilli
anthrax
what is an example of a disease causes by clostridium
tetanus or botulism
endospores are highly resistant to _______ and __________
heat and desiccation
what phase are endospores formed in
stationary
returning favorable environment conditions cause the protective layers of the endospore to _________
break down
after the protective layer of endospores break down, what happens
the spore germinates into a vegetative cell
between what degrees celsius are psychrophiles most optimal for growth
-10 and 20
between what degrees celsius are psychotrophs most optimal for growth
0 and 30
between what degrees celsius are mesophiles most optimal for growth
10 and about 50
between what degrees celsius are thermophiles most optimal for growth
40 and about 72
between what degrees celsius are hyperthermophiles most optimal for growth
about 68 and 110
the majority of species grow optimally at a _________ pH
neutral
what are species called that growth optimally at a neutral pH
neutrophiles
acid tolerant bacteria
acidophiles
what are two examples of acidophiles
lactobacillus and streptococcus
extreme acidophilus are typically __________
archaea
grow best at pH levels above 9
alkaliphiles
need salty/hypersaline conditions for optimal growth
halophiles
what prefers 2-5% NaCl
vibrio cholerae
what is an example of an extreme halophile
halo bacterium salinarium
what percent of NaCl do extreme halophiles grow at
20-30%
what is an example of a nonhalophile
E. coli
What percent of NaCl do nonhalophiles grow best at
less than 2%
What is an example of a halotolerant bacteria
staphylococcus
what percent of NaCl do halotolerants grow best at
non saline or slightly saline but only up to 8%
requires oxygen to grow
obligate aerobes
live in low oxygen environments
microaerophiles
do not or cannot use oxygen
anaerobes
species are insensitive to oxygen
aerotolerant
are inhibited or killed by oxygen
obligate anaerobes
grow either with oxygen or in reduced oxygen environments
facultative anaerobes
require an atmosphere low in oxygen and rich in carbon dioxide
capnophilic bacteria
what are the two basic types of culture media
complex medium and chemically defined medium
some components are exactly known, but other components include plant digests, animal digests, or yeast extracts or unknown composition
complex medium
the precise chemical composition of all additives is known
chemically defined medium
inhibits growth of certain species and allows the growth of others
selective medium
contains specific chemical to indicate species that possess or lack a biochemical process
differential medium
some fastidious organisms require an ____________ containing specific nutrients
enriched medium
