BIO 171 MODULE 4 EXAM WITH 100%
CORRECT ANSWERS 2026
What is another name for a liquid growth media, and what are the basic
components? correct answer Growth media in a liquid form is often referred to
as nutrient broth. As the name implies its composition consists primarily of
essential 'ingredients' such as a rich source of sugars, amino acids and vitamins.
Together, a nutrient broth provides the microbe with a source of carbon/energy,
which, in turn, encourages its expansion.
What is selective media? correct answer Selective media allows for only the
growth of certain microbes while restricting the growth of all others
What is differential media correct answer Differential media is used to
distinguish between two (or more) related microbes.
Is media distinguish two often related microbes. Ex: E. Coli and salmonella. They
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.
What are the requirements of a fastidious microbe? correct answer fastidious
microbe is an organism with complex growth requirements such that if absent it
will not grow. Enriched medias thus contain these specific and essential nutrients
required for the growth of a particular subset of microorganisms.
, What is agar? correct answer In its simplest form agar is liquid growth media
that has had a hardening agent added to it. Agar is created when a polysaccharide
derived from seaweed (algae) extract is added to growth media. Agar is used to
create a solid, smooth surface on which microbes can grow.
True or False: LB agar is classified as a non-selective, differential media correct
answer LB agar is both a non-selective and non-differential media. LB agar is often
used to expand unknown microbial population because it encourages microbial
growth due to the presence of universal nutrients (non-differential) and absence
of restrictive factors (non-selective).
What are the three forms of hemolysis found on blood agar plates? correct
answer Alpha (green), Beta (clear zones) and Gamma (white/tan). Microbes
capable of alpha hemolysis present with greenish-brown color colonies due to the
incomplete (partial) lysis of red blood cells. Beta hemolysis is classified as the
capacity of a microbe to completely lyse red blood cells. The resulting lysis
presents as a distinct zone of clearing around the growing colony. Gamma
hemolysis designates the absence or lack of hemolytic activity and the resulting
colonies are often white/tan in color growing on the red background color of the
unaffected blood agar plate.
What is the primary purpose of Columbia CNA agar? correct answer As it
suppresses the growth of Gram-negative bacteria CNA agar is, therefore, used for
isolation of Gram-positive microbes.
Name the type of plate derived from BAP that contains lysed red blood cells.
correct answer Lysed red blood cells (RBCs) are a primary component in the
formulation of Chocolate agar.
CORRECT ANSWERS 2026
What is another name for a liquid growth media, and what are the basic
components? correct answer Growth media in a liquid form is often referred to
as nutrient broth. As the name implies its composition consists primarily of
essential 'ingredients' such as a rich source of sugars, amino acids and vitamins.
Together, a nutrient broth provides the microbe with a source of carbon/energy,
which, in turn, encourages its expansion.
What is selective media? correct answer Selective media allows for only the
growth of certain microbes while restricting the growth of all others
What is differential media correct answer Differential media is used to
distinguish between two (or more) related microbes.
Is media distinguish two often related microbes. Ex: E. Coli and salmonella. They
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.
What are the requirements of a fastidious microbe? correct answer fastidious
microbe is an organism with complex growth requirements such that if absent it
will not grow. Enriched medias thus contain these specific and essential nutrients
required for the growth of a particular subset of microorganisms.
, What is agar? correct answer In its simplest form agar is liquid growth media
that has had a hardening agent added to it. Agar is created when a polysaccharide
derived from seaweed (algae) extract is added to growth media. Agar is used to
create a solid, smooth surface on which microbes can grow.
True or False: LB agar is classified as a non-selective, differential media correct
answer LB agar is both a non-selective and non-differential media. LB agar is often
used to expand unknown microbial population because it encourages microbial
growth due to the presence of universal nutrients (non-differential) and absence
of restrictive factors (non-selective).
What are the three forms of hemolysis found on blood agar plates? correct
answer Alpha (green), Beta (clear zones) and Gamma (white/tan). Microbes
capable of alpha hemolysis present with greenish-brown color colonies due to the
incomplete (partial) lysis of red blood cells. Beta hemolysis is classified as the
capacity of a microbe to completely lyse red blood cells. The resulting lysis
presents as a distinct zone of clearing around the growing colony. Gamma
hemolysis designates the absence or lack of hemolytic activity and the resulting
colonies are often white/tan in color growing on the red background color of the
unaffected blood agar plate.
What is the primary purpose of Columbia CNA agar? correct answer As it
suppresses the growth of Gram-negative bacteria CNA agar is, therefore, used for
isolation of Gram-positive microbes.
Name the type of plate derived from BAP that contains lysed red blood cells.
correct answer Lysed red blood cells (RBCs) are a primary component in the
formulation of Chocolate agar.
