Bio M118L: Quiz 2, M118L Quiz 2, Quiz 2, BIO SCI M118L Quiz 2
Questions and Answers
Question 1.
What is the difference between spectrum of activity and mode of action
Correct Answer: - spectrum of activity is the class of an organism targeted by
antibiotic - Mode of action is what the antibiotic actually does to the organism
(kill or inhibit its growth; broad or narrow spectrum?)
Question 2.
Broad spectrum antibiotics
Correct Answer: affect most bacteria
Question 3.
Describe true motility.
Correct Answer: Individual cells will be darting around the field of view. Not all
cells need to be motile, but different cells should be moving in different
directions. Quick darting is indicative of cells with polar flagella. If you see
slower motion, this may be indicative of peritrichous flagella.
Question 4.
How do you prepare cells for a Kirby Bauer experiment?
Correct Answer: put in mueller-hinton broth; add sufficient amount of cells the
turbidity matched that of the 0.5 McFarland turbidity standard (BaSO4
standard)
Question 5.
What is the purpose of adding Iodine after the crystal violet step?
Correct Answer: It forms a complex with the crystal violet to increase the size of
the dye
Question 6.
How do bacteria become antibiotic resistant?
Correct Answer: through the mutation of the bacterial genome; chemical
mutagens, UV light, spontaneous modification of nucleotides, and DNA
polymerase errors can all result in the alteration of the genome the acquisition
of a plasmid (circular DNA that can be obtained through horizontal gene
transfer; a single plasmid can encode for one or a few different genes, and may
function in the inactivation of an antibiotic, modification of a target enzyme, or
the inhibition of drug import
Question 7.
What is an ideal antibiotic able to do?
Correct Answer: harm the infecting agent while not affecting the host cells
Question 8.
Define antibiotics
Correct Answer: > Naturally made compounds that inhibit the growth (static) or
kill (cidal) pathogens > Derived usually from yeast or bacteria
,Question 9.
Standard parameters of Kirby Bauer experiment...
Correct Answer: - fresh bacterial culture - organisms are plated at a specific
density - constant concentration of antibiotic - incubated at a standardized
temperature
Question 10.
How many sets of controls do you need on a slide?
Correct Answer: Only one set
Question 11.
What is Brownian motion?
Correct Answer: random drifting of particles in a liquid due to collisions between
cells or molecs in the water
Question 12.
Define zone of inhibition
Correct Answer: Where no bacterial growth occurs
Question 13.
Why is a fresh culture of bacteria needed for Kirby Bauer?
Correct Answer: only fresh cells' log phase (in which DNA replication,
translation, and cell wall synthesis) can be interrupted by antibiotic
Question 14.
Describe the characteristics of yeast.
Correct Answer: eukaryotic and typically unicellular; individual cells typically
much larger than bacterial cells; most divide asexually by fission or budding
(unlike bacterial cells) do not possess flagella
Question 15.
Why would bacteria form endospores?
Correct Answer: > Spores are generally formed under stressful environmental
conditions (ex: lack of nutrients)
Question 16.
I have rod cells that are purple in color when gram stained. The catalase and oxidase tests
were negative. The experimental phenol red tube turned yellow. The minimal media tube
showed no growth. I saw motility in the wet mount and no fluorescent pigment in the Kings
Agar B test. Green refractile endospores were obtained after staining with malachite
green. What is the ABA DABA designation?
Correct Answer: +BBA
Question 17.
A single resistant bacterium within a colony of millions can result in ___________
Correct Answer: an antibiotic strain
, Question 18.
What is produced by strict aerobes and facultative anaerobes during ATP generation?
Correct Answer: H2O2 and O2- highly reactive and damaging compounds
Question 19.
How is the susceptibility of bacteria to the antibiotic measured?
Correct Answer: by measuring the diameter of the zone of inhibition
Question 20.
What is the purpose of the destainer in Gram Staining?
Correct Answer: Washes away crystal violet and shrinks the pores of the
peptidoglycan cell wall (larger in G+). The Crystal violet-Iodine complex is too
big to leave the pores, so it stays in the cell walls of Gram + cells.
Question 21.
We use an _____ ______ so that we....
Correct Answer: - inoculating needle - don't introduce too many cells or rich
medium agar into the tube
Question 22.
What is the ideal antibiotic?
Correct Answer: they can harm the infecting agent but not the host cells
Question 23.
What does a positive oxidase test look like?
Correct Answer: Purple-black color on the Oxidase paper after a minute
Question 24.
Catalase
Correct Answer: breaks down hydrogen peroxide and forms oxygen gas
Question 25.
Minimal media is a _____ medium containing _____ _____ as the ______ source and ____ _____
as the _____ source
Correct Answer: - defined - sodium succinate - carbon - ammonium chloride -
nitrogen
Question 26.
How does the Kirby Bauer experiment test for antibiotic sensitivity?
Correct Answer: If an organism's growth is affected on a solid medium, which
contains the antibiotic
Question 27.
How to use proper sterile technique on soil plating method
Correct Answer: - pick up plate from agar side - place the lid back on as soon as
you are done sampling or inoculating
Questions and Answers
Question 1.
What is the difference between spectrum of activity and mode of action
Correct Answer: - spectrum of activity is the class of an organism targeted by
antibiotic - Mode of action is what the antibiotic actually does to the organism
(kill or inhibit its growth; broad or narrow spectrum?)
Question 2.
Broad spectrum antibiotics
Correct Answer: affect most bacteria
Question 3.
Describe true motility.
Correct Answer: Individual cells will be darting around the field of view. Not all
cells need to be motile, but different cells should be moving in different
directions. Quick darting is indicative of cells with polar flagella. If you see
slower motion, this may be indicative of peritrichous flagella.
Question 4.
How do you prepare cells for a Kirby Bauer experiment?
Correct Answer: put in mueller-hinton broth; add sufficient amount of cells the
turbidity matched that of the 0.5 McFarland turbidity standard (BaSO4
standard)
Question 5.
What is the purpose of adding Iodine after the crystal violet step?
Correct Answer: It forms a complex with the crystal violet to increase the size of
the dye
Question 6.
How do bacteria become antibiotic resistant?
Correct Answer: through the mutation of the bacterial genome; chemical
mutagens, UV light, spontaneous modification of nucleotides, and DNA
polymerase errors can all result in the alteration of the genome the acquisition
of a plasmid (circular DNA that can be obtained through horizontal gene
transfer; a single plasmid can encode for one or a few different genes, and may
function in the inactivation of an antibiotic, modification of a target enzyme, or
the inhibition of drug import
Question 7.
What is an ideal antibiotic able to do?
Correct Answer: harm the infecting agent while not affecting the host cells
Question 8.
Define antibiotics
Correct Answer: > Naturally made compounds that inhibit the growth (static) or
kill (cidal) pathogens > Derived usually from yeast or bacteria
,Question 9.
Standard parameters of Kirby Bauer experiment...
Correct Answer: - fresh bacterial culture - organisms are plated at a specific
density - constant concentration of antibiotic - incubated at a standardized
temperature
Question 10.
How many sets of controls do you need on a slide?
Correct Answer: Only one set
Question 11.
What is Brownian motion?
Correct Answer: random drifting of particles in a liquid due to collisions between
cells or molecs in the water
Question 12.
Define zone of inhibition
Correct Answer: Where no bacterial growth occurs
Question 13.
Why is a fresh culture of bacteria needed for Kirby Bauer?
Correct Answer: only fresh cells' log phase (in which DNA replication,
translation, and cell wall synthesis) can be interrupted by antibiotic
Question 14.
Describe the characteristics of yeast.
Correct Answer: eukaryotic and typically unicellular; individual cells typically
much larger than bacterial cells; most divide asexually by fission or budding
(unlike bacterial cells) do not possess flagella
Question 15.
Why would bacteria form endospores?
Correct Answer: > Spores are generally formed under stressful environmental
conditions (ex: lack of nutrients)
Question 16.
I have rod cells that are purple in color when gram stained. The catalase and oxidase tests
were negative. The experimental phenol red tube turned yellow. The minimal media tube
showed no growth. I saw motility in the wet mount and no fluorescent pigment in the Kings
Agar B test. Green refractile endospores were obtained after staining with malachite
green. What is the ABA DABA designation?
Correct Answer: +BBA
Question 17.
A single resistant bacterium within a colony of millions can result in ___________
Correct Answer: an antibiotic strain
, Question 18.
What is produced by strict aerobes and facultative anaerobes during ATP generation?
Correct Answer: H2O2 and O2- highly reactive and damaging compounds
Question 19.
How is the susceptibility of bacteria to the antibiotic measured?
Correct Answer: by measuring the diameter of the zone of inhibition
Question 20.
What is the purpose of the destainer in Gram Staining?
Correct Answer: Washes away crystal violet and shrinks the pores of the
peptidoglycan cell wall (larger in G+). The Crystal violet-Iodine complex is too
big to leave the pores, so it stays in the cell walls of Gram + cells.
Question 21.
We use an _____ ______ so that we....
Correct Answer: - inoculating needle - don't introduce too many cells or rich
medium agar into the tube
Question 22.
What is the ideal antibiotic?
Correct Answer: they can harm the infecting agent but not the host cells
Question 23.
What does a positive oxidase test look like?
Correct Answer: Purple-black color on the Oxidase paper after a minute
Question 24.
Catalase
Correct Answer: breaks down hydrogen peroxide and forms oxygen gas
Question 25.
Minimal media is a _____ medium containing _____ _____ as the ______ source and ____ _____
as the _____ source
Correct Answer: - defined - sodium succinate - carbon - ammonium chloride -
nitrogen
Question 26.
How does the Kirby Bauer experiment test for antibiotic sensitivity?
Correct Answer: If an organism's growth is affected on a solid medium, which
contains the antibiotic
Question 27.
How to use proper sterile technique on soil plating method
Correct Answer: - pick up plate from agar side - place the lid back on as soon as
you are done sampling or inoculating
