FINAL EXAM: MCB 2610 Lab final Exam with Certified
Solutions
The ______ _______ method is a quick and easy way to isolate bacteria CORRECT ANS-
streak plate
In what orientation do you incubate the plates after they have been streaked? CORRECT
ANS-agar half bottom
What must you do to the loop before every use? CORRECT ANS-flame it
T/F: The last thing you do before leaving the lab is take off your lab coat CORRECT ANS-
false
streaked plate method CORRECT ANS-culture is spread out on agar to make isolated
colonies
solid media (agar plates) CORRECT ANS-used to isolate bacteria
liquid culture media (broth) CORRECT ANS-used to grow cells to high densities
, FINAL EXAM: MCB 2610 Lab final Exam with Certified
Solutions
T/F: When making a smear of the culture, you heat fix the slide before air drying it completely
CORRECT ANS-false
What is the magnification value of the ONLY objective that should come in contact with
immersion oil? CORRECT ANS-100x
Pertaining to the Gram stain, cells that retain the primary stain and appear purple are said to
be Gram CORRECT ANS-positive
What cellular structure does the counterstain safranin stain? CORRECT ANS-outer
membrane
direct stain CORRECT ANS-stains the organism itself
indirect or negative stain CORRECT ANS-stains the background
, FINAL EXAM: MCB 2610 Lab final Exam with Certified
Solutions
simple stain CORRECT ANS-use only one stain to determine cell morphology, size and
arrangement
Gram staining stains the cell __________, while spore staining stains for __________.
CORRECT ANS-cell envelope, endospores
Gram Positive cell characteristics CORRECT ANS-thick peptidoglycan layer, retains crystal
violet, no outer membrane
Gram Negative cell characteristics CORRECT ANS-thin layer of peptidoglycan, doesn't retain
crystal violet, has outer membrane, safranin counterstains membrane pink
Gram stain steps and time CORRECT ANS-1. crystal violet, 1 minute, 2. iodine, 1 minute, 3.
ethanol, 15-30 seconds, 4. safranin, 30 seconds
Why do bacteria form endospores? CORRECT ANS-under environmental stress
In a spore stain, endospores retain _________ (what color). CORRECT ANS-malachite green
Solutions
The ______ _______ method is a quick and easy way to isolate bacteria CORRECT ANS-
streak plate
In what orientation do you incubate the plates after they have been streaked? CORRECT
ANS-agar half bottom
What must you do to the loop before every use? CORRECT ANS-flame it
T/F: The last thing you do before leaving the lab is take off your lab coat CORRECT ANS-
false
streaked plate method CORRECT ANS-culture is spread out on agar to make isolated
colonies
solid media (agar plates) CORRECT ANS-used to isolate bacteria
liquid culture media (broth) CORRECT ANS-used to grow cells to high densities
, FINAL EXAM: MCB 2610 Lab final Exam with Certified
Solutions
T/F: When making a smear of the culture, you heat fix the slide before air drying it completely
CORRECT ANS-false
What is the magnification value of the ONLY objective that should come in contact with
immersion oil? CORRECT ANS-100x
Pertaining to the Gram stain, cells that retain the primary stain and appear purple are said to
be Gram CORRECT ANS-positive
What cellular structure does the counterstain safranin stain? CORRECT ANS-outer
membrane
direct stain CORRECT ANS-stains the organism itself
indirect or negative stain CORRECT ANS-stains the background
, FINAL EXAM: MCB 2610 Lab final Exam with Certified
Solutions
simple stain CORRECT ANS-use only one stain to determine cell morphology, size and
arrangement
Gram staining stains the cell __________, while spore staining stains for __________.
CORRECT ANS-cell envelope, endospores
Gram Positive cell characteristics CORRECT ANS-thick peptidoglycan layer, retains crystal
violet, no outer membrane
Gram Negative cell characteristics CORRECT ANS-thin layer of peptidoglycan, doesn't retain
crystal violet, has outer membrane, safranin counterstains membrane pink
Gram stain steps and time CORRECT ANS-1. crystal violet, 1 minute, 2. iodine, 1 minute, 3.
ethanol, 15-30 seconds, 4. safranin, 30 seconds
Why do bacteria form endospores? CORRECT ANS-under environmental stress
In a spore stain, endospores retain _________ (what color). CORRECT ANS-malachite green
