BIO 171 MODULE 4 EXAM WITH 100% CORRECT ANSWERS 2026

BIO 171 MODULE 4 EXAM WITH 100%
CORRECT ANSWERS 2026


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