MCB 2610 Lab Practical
Pertaining to the Gram Stain, cells that retain crystal violet & appear purple are said to be __________ -
Gram positive
Pertaining to the Gram Stain, cells that do not retain crystal violet & appear pink are said to be Gram
________ - Negative
coliform are a subgroup of enteric bacteria classified by their ability to ferment which sugar? -
lactose
define generation time - the time required for the population to double in number
growth only along the path of the inoculating needle indicates that the bacteria is _______ - non
motile
how is casein hydrolysis detected? - a clear zone is seen around colonies where the casein has
been digested
How to gram stain - label slide
spread sample on slide
allow to air dry
heat fix
flood with crystal violet (1 minute)
wash with Di water
flood with iodine (1 minute)
wash with water
drop Ethanol until no more color comes off
wash with water
flood with safranin (30 sec)
, wash with water
blot dry gently with bibulous paper
in what orientation do you incubate the plates after they have been streaked? - agar half on top
MacConkey agar selects for _______ bacteria - Gram negative
________ will occur around the colonies, indicating amylase production and starch utilization -
clearing zone
motile bacteria use which organelle for propulsion? - flagellum
T/F: a vegetative cell is formed in response to certain environmental conditions such as depletion of
nutrients - False
T/F: brownian motion is the purposeful movement of microorganisms - False
T/F: complex media is made with a precise chemical composition - False
T/F: ethanol is used as a mordant during Gram staining - False
T/F: generation time is calculated in log phase - True
T/F: Gram stains and spore stains are examples of simple stains - False
T/F: heat during staining causes sporulation - False
T/F: heat used during staining does not cause sporulation - True
Pertaining to the Gram Stain, cells that retain crystal violet & appear purple are said to be __________ -
Gram positive
Pertaining to the Gram Stain, cells that do not retain crystal violet & appear pink are said to be Gram
________ - Negative
coliform are a subgroup of enteric bacteria classified by their ability to ferment which sugar? -
lactose
define generation time - the time required for the population to double in number
growth only along the path of the inoculating needle indicates that the bacteria is _______ - non
motile
how is casein hydrolysis detected? - a clear zone is seen around colonies where the casein has
been digested
How to gram stain - label slide
spread sample on slide
allow to air dry
heat fix
flood with crystal violet (1 minute)
wash with Di water
flood with iodine (1 minute)
wash with water
drop Ethanol until no more color comes off
wash with water
flood with safranin (30 sec)
, wash with water
blot dry gently with bibulous paper
in what orientation do you incubate the plates after they have been streaked? - agar half on top
MacConkey agar selects for _______ bacteria - Gram negative
________ will occur around the colonies, indicating amylase production and starch utilization -
clearing zone
motile bacteria use which organelle for propulsion? - flagellum
T/F: a vegetative cell is formed in response to certain environmental conditions such as depletion of
nutrients - False
T/F: brownian motion is the purposeful movement of microorganisms - False
T/F: complex media is made with a precise chemical composition - False
T/F: ethanol is used as a mordant during Gram staining - False
T/F: generation time is calculated in log phase - True
T/F: Gram stains and spore stains are examples of simple stains - False
T/F: heat during staining causes sporulation - False
T/F: heat used during staining does not cause sporulation - True
