BIOD 171 Portage Learning Exam 4 With
Complete Solution
What is another name for a liquid growth media, what are the basic components? -
ANSWER Nutrient broth. The basic components are sugar, amino acids, and vitamins.
What is selective media? - ANSWER Selective media is when you only allow certain
microbes to grow while restricting the growth of the other microbes.
What is differential media? - ANSWER Differential media is used to differentiate between
two or more related microbes.
What does a fastidious media require? - ANS Fastidious media have complicated growth
requirements. If it lacks something, then it will not grow.
What is agar? - ANS It is a liquid growth media that has a hardening agent. It is used to
give way for microbes to grow.
TRUE or FALSE: LB agar is a type of non-selective, differential media. - ANS FALSE
Name the three forms of hemolysis present on blood agar plates. - ANSWER Alpha
hemolysis: greenish, brown from incomplete lysis of red blood cells
Beta hemolysis: ability 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: white/tan in color w/ red background.
, What is the primary purpose of Columbia CNA agar? ANSWER It is used to isolate
Gram-positive microbes.
What type of plate is there that is prepared with BAP and possesses lysed RBCs?
ANSWER Lysed RBCs.
Describe and name the selective and differential capabilities of a MacConkey agar plate.
- ANSWER It is selective because only Gram-negative microbes can grow on it. It is
differential since it can tell the difference between microbes that can ferment lactose
and those that cannot.
What colors would you expect to see on an EMB plate containing E. coli.? - ANSWER A
green sheen.
What is the term for the process of spreading a bacterial culture onto a Petri dish? -
ANSWER Plating.
What is the major advantage of plating a bacterial culture as opposed to having it grow
in solution? - ANSWER The advantage is that it holds the cells in place.
What is the purpose of the quadrant streak approach? - ANSWER To generate an
individual colony so a single pure culture can be picked.
In a three-phased dilution gradient, which phase most likely contains individual
colonies: phase 1 or phase 3? - ANSWER Phase 3 streaks.
A
Sorbitol- MacConkey Agar: PINK, TO detect the presence of the pathogenic strain or
E.coli.
Complete Solution
What is another name for a liquid growth media, what are the basic components? -
ANSWER Nutrient broth. The basic components are sugar, amino acids, and vitamins.
What is selective media? - ANSWER Selective media is when you only allow certain
microbes to grow while restricting the growth of the other microbes.
What is differential media? - ANSWER Differential media is used to differentiate between
two or more related microbes.
What does a fastidious media require? - ANS Fastidious media have complicated growth
requirements. If it lacks something, then it will not grow.
What is agar? - ANS It is a liquid growth media that has a hardening agent. It is used to
give way for microbes to grow.
TRUE or FALSE: LB agar is a type of non-selective, differential media. - ANS FALSE
Name the three forms of hemolysis present on blood agar plates. - ANSWER Alpha
hemolysis: greenish, brown from incomplete lysis of red blood cells
Beta hemolysis: ability 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: white/tan in color w/ red background.
, What is the primary purpose of Columbia CNA agar? ANSWER It is used to isolate
Gram-positive microbes.
What type of plate is there that is prepared with BAP and possesses lysed RBCs?
ANSWER Lysed RBCs.
Describe and name the selective and differential capabilities of a MacConkey agar plate.
- ANSWER It is selective because only Gram-negative microbes can grow on it. It is
differential since it can tell the difference between microbes that can ferment lactose
and those that cannot.
What colors would you expect to see on an EMB plate containing E. coli.? - ANSWER A
green sheen.
What is the term for the process of spreading a bacterial culture onto a Petri dish? -
ANSWER Plating.
What is the major advantage of plating a bacterial culture as opposed to having it grow
in solution? - ANSWER The advantage is that it holds the cells in place.
What is the purpose of the quadrant streak approach? - ANSWER To generate an
individual colony so a single pure culture can be picked.
In a three-phased dilution gradient, which phase most likely contains individual
colonies: phase 1 or phase 3? - ANSWER Phase 3 streaks.
A
Sorbitol- MacConkey Agar: PINK, TO detect the presence of the pathogenic strain or
E.coli.
