Chapter 3 Flashcards
What is a light microscope ?
Any kind of microscope that uses visible light to observe a specimen
What are the types of lens that light microscope use to magnify the image
objective lens
ocular lens
What is the range of magnification of the objective lens ?
10x -100x
What is the range of magnification of the ocular lens ?
10x
How to calculate total magnification using light microscope ?
Objective lens x Ocular lens
What is resolution ?
It is the ability to distinguish fine detail
and structure
What is resolution general principle ?
the shorter the wavelength, the
better the resolution
Between the light and electron microscope which one has a greater resolving power
Electron microscope
What is the range of magnification of electron microscope ?
up to 500 000 X
What is the function of an electron microscope ?
Allows us to view viruses
and internal cell structures.
What are the types of electron microscope ?
Transmission(TEM)
Scanning (SEM)
Which electron microscope is less powerful ?
Scanning0
How far can a human eye sees ?
0.2mm
How far can a light microscope view an object ?
0.2 micrometer
How far can a electron microscope view an object ?
2 nm
What are the named of positively and negatively charged ions in stains ?
chromophore
Positive stains
Stain will bind to the bacterium
• Bacterium appears colored
• Background appears clear
• Ex. Crystal violet
Negative stain
Will not bind to the bacterium
• Bacterium appears clear
• Background is colored
• Ex. nigrosin.
What is function of spore stain ?
stains an internal structure of some bacteria
What is the primary stain colour of spore stain ?
endospores green
What is the function of the flagella stain ?
Stains an external structure
What is the function of the acid fast stain ?
Detects the presence of a waxy compound in cell wall
What is the function of the capsule stain ?
Detects a thick layer of polysaccharide outside the cell – capsule
