Chapter 3 Microscopy And Staining Flashcards
Be able to identify the various types of bacteria morphologies give him an image or diagram of bacteria.
Morphology is equal to the shape of a single cell
Coccus
Sphere
Bacillus
Rod
Spirochete
Elongated helix
Vibrio
Comma
Coccobacillus
Sphere and rod combined
*annoying
Identify arrangements of bacterial cells given an image or diagram of bacteria
Arrangements are equal to the how cells are grouped together
Strepto
Long chain
Staphylo
Irregular clumps
Streptobacillus
Rods in a chain
Streptococcus
Spheres in chain
Staphylococcus
Clumps of spheres
Diplococcus / diplobacillus
2 spheres
2 rods
Tetrads
4 spheres in a square
Know the basic unit of measurement commonly used to measure cell size
Micrometer 1/1,00,000 of a meter a.k.a. micron
Nanometer 1,000,000,000 of a meter
Atoms are a fraction of nanometer in size
Describe the parts and functions of the parts of a compound light microscope and be able to diagram the right path of a compound microscope
Parts From bottom to top
Light source,
condenser,
objective lens with variable magnification ocular lens 10x magnification
Light path from bottom to top Light source condenser specimen slide objective lens
Explain the purpose of immersion oil and why permits observation of bacteria 1000x magnification or higher
The light is not lost in oil is in the gap
hire magnification smaller field of view less light
Know the limitations of light microscopy.
Recognize the approximate resolution limit for light microscope’s
Light microscope’s 2000 x
10micrometers
Electron microscope 10,000,000 x mag
2 micrometers
Describe the protocol for heat fixing bacteria on a slide and no the reasons why he fixing is done
Aseptic technique smear Heat fix -Adheres bacteria to slide -Kills bacteria (useful) -Makes bacteria receptive to dyes stain
State the chemical difference between basic an acidic dies
Basic dyes: positively charged
cation. Bacteria and negatively charged therefore a very attracted to basic dyes
Examples: methylene blue crystal violet Malachi green safranin
Acidic dyes: Negatively charged anions
Dye has the same charge as most cells negative staining the day is excluded from the seller leaving colorless against stain background. Good for morphology
Examples: eosin nigrosin
What is the function of a mordant
Chemicals that intensify the appearance of the dye by improving binding or trapping the dye
Which type of staining is the Gram stain? What about the acid fast stain?
Differential stains
If I apply methylene blue to bacteria that has been heat fixed to slide and wash off the dye, add a drop of emotion oil, and observe, what Stan do I have
Simple stain
What genre are identified using the acid fast stain
Used to identify genre mycobacterium, nocardia, Mycobacterium tuberculosis, microbacterium leprae
These contain sturdy cell wall containing my colic acid, wax is, complex lipids
Acid-fast means they keep the stain even when treated with acid
Given an image of an acid fast stain, Identify the bacteria that are acid-fast
Primary stain Carbolfusion red
Counterstain methylene blue
Acid fast bacteria are red
Given an image of mixed culture that has been Graham stained,The able to identify which bacteria or gram-positive and which are Graham negative
Bacteria that retain crystal violet are gram-positive purple
bacteria that Are red and did not retain crystal violet a gram negative
the reason why the gram-positive bacteria appear Purple and not Red is due to the retention of crystal violet
counterstain allows visualization of the non-gram-positive cells
*Gram-positive bacteria do not decolorize Graham negative do
