Lab Practical #1 Flashcards
Ocular lens
Magnify by 10X. Two eye pieces to look into
Light switch/ light intensity knob
Found on the arm of the microscope. They turn on/off the lamp and control the brightness
Objective lens
Scan (4X)
Low (10X)
High (40X)
Oil (100X)
Magnification
Apparent increase in the size of an object
Total magnification rule
(Ocular power) multiplied by (objective power)
Example: 10(ocular) X 4 (scan objective) = 40X magnification
Condenser and iris diaphragm
Levels that control the amount of contrast that the microscope specimen lets in
Field of view
The area visible through the eye piece
Par focal
Once an object is in focus on scan power it will be in focus in the next power
What is resolution?
The fineness of detail that can be examined through a microscope
Field of view measurements
Scan- 4.5mm
Low- 1.8mm
High- .45mm
Oil- .18mm
Simple staining
Uses methylene blue stain
What color are the bacteria after you simple stain them?
Clear
Why do we heat a slide?
Kills the bacteria, fixes bacteria to the slide
If the bacteria after being stained is purple then the bacteria will be?
A gram positive organism
Example: megaterium
S.epidermis
If the bacteria that is being stained looks pink/red then the bacteria is?
A gram negative organism
Example: S. Macresens
What is a differential stain?
Staining procedure that uses more than one stain to differentiate between cell structures. This helps in the identification of bacteria.
What does a Gram stain do?
Stains for the cell wall of the bacteria.
Gram +
Purple
Gram -
Pink
What is the purpose of an acid fast stain?
To stain bacteria that have mycolic acid in the cell wall
What is mycolic acid?
Is a lipid that prevents bacteria from being stained by most stains
What stains are used in an acid fast stain?
Primary stain- carbolfuchion (red color)
Counter stain- methylene blue (blue color)
Phenol- helps the primary stain penetrate the mycolic acids cell wall
If it is an acid fast positive it will be?
Red color
Example: M. Smegmatis
(Rod shaped)
If it is an acid fast negative, it will be?
Blue
Example: s.epidermis
(Round shape)
What are flagella used for?
Movement or motility
