Microbiology: Test 1: Chapter 3

Front 1

1. What microscope achieves the greatest magnification of living cells and cell structures with the highest resolution

Back 1

Electron transmission microscope

Front 2

2) After Gram staining, what color are Gram negative?....Gram positive?

Back 2

Gram Positive Purple, Gram negative pink/red.

Front 3

3) List, in order, the 4 chemicals used in Gram staining. Know the color of Gram – and Gram + after each step

Back 3

a. Crystal violet = primary stain = everything purple
b. Iodine = both appear dark violet/purple
c. Alcohol wash = decolorizing agent = gram positive stay purple, negative lose color
d. Safranin = red dye = gram negative are red, positive are purple

Front 4

4) What microscope would you use to view intracellular structures in a natural state? How does this scope work?

Back 4

a. Phage contrast MS. Bright contrast with no fixing so no distortions or killing the organism

Front 5

The smaller the _____________of light, the better the ___________________ of the microscope

Back 5

The smaller the _____wavelength__________of light, the better the _____resolution_______________of the microscope

Front 6

How do you obtain total magnification of a microscope?

Back 6

Multiply the power of the objective by the power of the eyepiece

Front 7

Malachite green and safranin are used in ______________________staining.

Back 7

Endospore (basic)

Front 8

________________ microscopy allows specimens to emit light when exposed to UV rays.

Back 8

a. Fluorescence

Front 9

What is accomplished in heat-fixing?

Back 9

1) Get organisms to stick to slide
2) Kills organism
3) Coagulates proteins to better absorb the stain

Front 10

1. What is the function of the ocular lens?

Back 10

1. Magnifies an image created by the objective lens

Front 11

When would you use a negative stain?

Back 11

Preparing colorless bacteria against a colored background) To observe overall cell shapes, sizes, and capsules. Distortion are minimal because fixing is not necessary and the cells do not pick up the stain

And flagella

Front 12

12) What are the 3-4 steps done in lab to view bacterial cells using methylene blue or safranin?

Back 12

a. Create a smear, air dry or heat fix, stain with methylene blue or safranin, wash with water and dry with special paper

Front 13

List the basic stains discussed in class and used in lab. List the acidic stains.

Back 13

a. Basic: methylene blue, safranin, malachite green
b. Acidic: Congo red, carbolfusion, nigrosin

Front 14

Why do Mycobacteria tuberculosis appear gram +although they are not?

Back 14

They have a mycolicacid cell wall which is neither gram positive nor gram negative. Use an acid fast stain. It shows gram + first and then you acid stain. Blue bacteria do not have a waxy cell wall, leaving red mycobacteria. Acid fast stain : steaming to melt the waxy cell wall, which aborbs the negative stain (carbolfuchsin)

Front 15

CM to MM to UM to NM

Back 15

1 cm = 10 mm

1 mm = 1000 um

1 um = 1000 nm

Front 16

Glass lenses

Back 16

(ocular and objective) Bends light and magnifys

Front 17

Refractive index

Back 17

Ability of a medium to bend light (IE shallow pool)

Oil immersion same index as glass

Front 18

Artifacts

Back 18

Distortions

Front 19

Diffraction

Back 19

ability of a medium to break up light to different wavelength colors (diamond or raindrop)

Front 20

Resolution

Back 20

ability of a microscope to distinguish between two objects that are close together. Shorter wavelength = better resolution

Front 21

Phase contrast microscope

Back 21

bright field. No fixing or staining (no artifacts - false distortions)

objective lenses to amplify wave lengths. To see living organisms without artifacts.

Front 22

Flourescence microscope

Back 22

flourescent stained organisms (glow in the dark) Dark field. Florochrone is the dye. (lock and key)

Front 23

Confocal microscope

Back 23

Dark field. Florescent dye. Camera to computer - very thin plains put together for a 3D blueprint

(living organism)

Front 24

Electron Microscope

Back 24

electrons are the illuminating source, shorter wave lengths and magnetic lenses so electrons an be deflected

Front 25

Microtome

Back 25

Means to cut very thin - shows how thin you can get something without damaging internal structure

(Shows silver - ie silver in a puddle is thinest)

Front 26

Transmission Electron microscope

Back 26

HUNDREDS of thousands of times

Looking inside, flat image (2D)

Highest magnification for living material

Front 27

Scanning electron microscope

Back 27

ten's of thousands of times

Less magnification but 3D. (Outside cells)

Front 28

Scanned probed microscope

Back 28

Shows how atoms and molecules interact (inside cell) 3D. No artifacts

Chemists and physicists

Front 29

Scanning TUnnelling Microscope

Back 29

Tungesten probe, shows interactions inside organelles, etc.

Front 30

Atomic Force microscope

Back 30

diamond and metal probes to look at 3D surfaces of atoms and molecules. Allows to see PROCESSES like nerve impulse and clotting

Front 31

Why do we use stains

Back 31

allows it to be seen

Front 32

Smear

Back 32

aspeptic (flame before and after) Need some wetness, add bacteria, make a thin puddle. Not too much bacteria

Front 33

Fixing (3 things)

Back 33

"zip zip" through flame

1)Kills organism

2) Gets organism to stick to slide

3) Coagulates proteins to better aborb the stain

Front 34

Basic stains

Back 34

release OH- and aborb H+ creating a POSITIVE charge. Cells have slight negative charge so the stain goes inside

4 basic stains: crystal voilet, methylene blue, safrinin, malicate green

Front 35

Acidic stain

Back 35

Negative stains - give H+ and absorb OH-.

Negative pigment is repelled by cell's charge. (Negative negative interaction) Thus stains background.

Congo red, Carbolfusion, Nicrosin

Front 36

Capsule staining

Back 36

staining "halo" (negative) stains capsule and flagella. DO NOT HEAT FIX. Air dry. Look for size, shape, delicate structures.

Front 37

EndoSPORE staining

Back 37

Schaffer fultin method. Malicate green stains spores green, saffrinin - allows bacteria to be pink/red. (XMAS)