Study online at https://quizlet.com/_hlz9lt
Growth media in a liquid form is often
referred to as nutrient broth. As the name
implies its composition consists primarily
What is another name for a liquid growth of essential 'ingredients' such as a rich
media, and what are the basic compo- source of sugars, amino acids and vita-
nents? mins. Together, a nutrient broth provides
the microbe with a source of carbon/en-
ergy, which, in turn, encourages its ex-
pansion.
Selective media allows for only the
What is selective media? growth of certain microbes while restrict-
ing the growth of all others
Differential media is used to distinguish
between two (or more) related microbes.
Is media distinguish two often related mi-
crobes. Ex: E. Coli and salmonella. They
What is differential media
can grow up in a differential media but
only E. Coli would react to lactose and
become red colored while salmonella will
stay white/tan in color.
fastidious microbe is an organism with
complex growth requirements such that
What are the requirements of a fastidi- if absent it will not grow. Enriched medias
ous microbe? thus contain these specific and essential
nutrients required for the growth of a par-
ticular subset of microorganisms.
In its simplest form agar is liquid growth
media that has had a hardening agent
added to it. Agar is created when a poly-
What is agar? saccharide derived from seaweed (al-
gae) extract is added to growth media.
Agar is used to create a solid, smooth
surface on which microbes can grow.
LB agar is both a non-selective and
True or False: LB agar is classified as a non-differential media. LB agar is often
non-selective, differential media used to expand unknown microbial pop-
ulation because it encourages microbial
1/7
, Bio 171 module 4 review
Study online at https://quizlet.com/_hlz9lt
growth due to the presence of universal
nutrients (non-differential) and absence
of restrictive factors (non-selective).
Alpha (green), Beta (clear zones) and
Gamma (white/tan). Microbes capable
of alpha hemolysis present with green-
ish-brown color colonies due to the in-
complete (partial) lysis of red blood cells.
Beta hemolysis is classified as the ca-
pacity of a microbe to completely lyse red
What are the three forms of hemolysis
blood cells. The resulting lysis presents
found on blood agar plates?
as a distinct zone of clearing around the
growing colony. Gamma hemolysis des-
ignates the absence or lack of hemolytic
activity and the resulting colonies are of-
ten white/tan in color growing on the red
background color of the unaffected blood
agar plate.
As it suppresses the growth of
What is the primary purpose of Columbia Gram-negative bacteria CNA agar is,
CNA agar? therefore, used for isolation of Gram-pos-
itive microbes.
Lysed red blood cells (RBCs) are a pri-
Name the type of plate derived from BAP
mary component in the formulation of
that contains lysed red blood cells.
Chocolate agar.
MacConkey agar is selective in that only
Gram-negative microbes will grow on the
agar—Gram-positive microbes simply do
not grow. MacConkey agar is also con-
Define the selective and differential abil-
sidered a differential media as it distin-
ities of a MacConkey agar plate.
guishes between microbes capable of
fermenting lactose (red colonies) and
those that are non-fermenters (white/tan
colonies).
What colors would you expect to see on
an EMB plate containing E. coli?
2/7