exam 3 Flashcards
anaerobic
only grows in the absence of oxygen
photoautotroph
produces energy using sunlight
aerobic
requires oxygen to grow
facultative
survives best at low oxygen
chemoautotroph
obtains its energy through chemicals
pathogenic
causes disease
gram-positive bacteria have
a cell membrane and a thick cell wall
gram-negative bacteria have
a cell membrane, a thin cell wall, and an outer phospholipid membrane
when bacteria undergo cell division, they are clones of their patent cell. true or false?
true
what are two key differences between prokaryotes and eukaryotes
prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms. eukaryotes also carry DNA in the nucleus while prokaryotes carry DNA in the nucleoid
media that prevents the growth of some type of microorganisms and permits the growth of others is said to be
selective
media that allows you to tell whether or not a colony has a particular property is called
differential
nutrient agar
contains all nutrients necessary for growth
eosin methylene blue
eosin, methylene blue
inhibits gram positive growth
blood agar
contains sheep’s blood
any kind of bacteria can grow
elongated, rod-shaped bacteria are called
bacilli
streptococcus
line of circular organisms
diplococcus
two circular organisms
coccus
one circular organism
streptobacilli
line of cylinder organisms
what is a differential agar that allows detection of hemolysis
blood
what is a non-selective and non-differential agar on which all non-fastidious microorganisms can grow
nutrient
what is a selective agar that only grows gram-negative bacteria and is differential for lactose fermentation
eosin methylene blue
alpha-hemolysis
green
beta-hemolysis
colorless ring
gamma-hemolysis
red (no change)
if no peptide bonds are present in a solution, the solution mixed with biuret reagent will appear
blue
if starch is present is a solution, the solution will turn what color when lugol’s solution is added
black
benedicts solution is used to detect the presence of this nutrient
sugar
biuret solution is used to detect the presence of this nutrient
proteins
lugol’s solution is used to detect the presence of this nutrient
starch
phenol red is used to detect digestion of triglycerides. why?
production of hydrogen ions changes the color
protein
amino acids
starch
glucose
lipids
fatty acids
at which pH does pepsin from the stomach work best
2.0
at which pH does lipase from pancreatic juice work best
7.0
pH
protein
substrate amount
lipid
glucose
temperture
starch
time
MacConkey
contains bile salts and crystal violet dye
inhibits gram positive growth
contains neutral red pH indicators
low pH - red
high pH - yellow
is the nutrient agar selective or differential
neither
is the MacConkey agar selective or differential
both
selective: inhibits gram positive growth
differential: ability to ferment lactose
is the EMB agar selective or differential
both
selective: inhibits gram positive growth
differential: ability to ferment lactose
is the blood agar selective or differential
non-selective
differential: identify organisms that have hemolytic activity
what grows on the nutrient agar
bacteria, yeast, mold
what grows on the MacConkey agar
gram negative bacteria
pink/red: able to ferment lactose
white/colorless/golden: unable to ferment lactose
what grows on the EMB agar
gram negative bacteria
metallic green: e. coli
pink/purple/black: able to ferment lactose
colorless: unable to ferment lactose
what grows on the blood agar
colony surrounded by green color: alpha hemolysis (incomplete lysis and digestion)
colony surrounded by white/clear: beta hemolysis (lysis/digestion)
Agar under/around colony is unchanged: gamma hemolysis (no hemolysis)
prokaryotes
archaea and bacteria
eukaryotes
eukarya
colony
visible cluster of identical bacteria that grew from one original bacterium
lawn
a dense covering of bacteria on a plate due to the colonies growing into each other
turbid
liquid broth that is cloudy due to bacterial growth
casein
protein found in milk
pepsin
secreted by the stomach as inactive pepsinogen and is then cleaved into its active form
