Crystal violet, rinse, mordant of iodine, rinse with alcohol, counterstain with safranin
What is used in performing a Gram's stain?
This type of stain does not penetrate the bacterial cell but rather causes the area around the cell to be dark.
The best way to determine bacterial size and cell morphology is to prepare a slide by a process called ________ staining.
Sucess at bacterial staining depends on the preparation of a suitable _______ of the organism.
To ensure shrinkage will not occur during staining, otherwise, distortion of artifacts will occur or to kill microbes.
Name one of the three goals in preparing a smear for staining.
Some bacterial cells are surrounded by an extracellular slime layer called a ________, and staining this layer cannot be accomplished by ordinary simple staining procedures.
Capsular staining combines the methods for the simple stain and the negative stain. True or False?
Bacteria that form endospores are less resistant than vegetative cells to the effects of UV light. True or False?
The function of the ______ in Gram staining is to complex with crystal violet to form a relatively insoluble complex in the gram positive bacteria.
False. (It's gram positive that can do this).
Old cultures of gram negative bacteria can convert to gram positive or gram variable and give erroneous results. True or False?
Heat is used in spore staining to enable the stain to penetrate the endospore, once there is not removed with either decolorizing agents or water. True or False?
Bacterial motility decrease with time so it is best to examine a wet mount slide immediately after it is prepared.
Brownian movement is vibrational movement caused by invisible molecules bombarding bacterial cells.
streak plate and pour plate methods.
The two commonly used procedures to separate organisms into pure cultures are the:
Standard plate count (aka viable count)
The _____ is one of the most common methods for determining bacterial numbers in a sample.
The safety of drinking water is dependent on there being no sewage contamination. The presence of ______ in potable water suggests the potential for disease.
30 and 300
After plates are innoculated and incubated, plates that have between _______ colonies are selected for counting.
Standard plate count.
In this lab exercise, two methods are used to determine the number of bacteria present in a culture sample. Name one of them.
__________ stains such as nigrosin and india ink do not penetrate the bacterial cell but rather cause the background area around a cell to become opaque or dark.
Capsule or glycocalyx
Some bacterial cells are surrounded by an extracellular slime layer called a ________