Mcb3020 Lab Practical

Front 1

Oil immersion lens uses oil with approximately the same refractive index as _____ to prevent light loss due to diffraction (bending of light rays) which would occur if light traveled from one refractive index to another

Back 1

glass

Front 2

In ___ ______ microscopy, the condenser directs light at oblique angles away from the objective lens in a manner that allows only objects in the field of view to redirect or scatter light into the objective lens. This causes objects to appear white on a dark field

Back 2

dark field

Front 3

As you close down the diaphragm:
1. The light intensity _____
2. Contrast ______
3. Depth of field ______
4. ____ Resolution (with oil immersion lens)

Back 3

decreases
improves
increases
Limit

Front 4

d = ?

Back 4

λ / 2 NA

Resolution

the diameter of the smallest resolvable object

Front 5

d can be decreased by _____ __ or _______ ____

Back 5

lowering λ
increasing NA

Front 6

_______ (_____) – divide in one plane
_______ (_____) – divide in one plane
_______ (_____) – divide in two planes
_________ (______) – divide in three planes irregularly
______ (____ ____) – divide in three planes regularly

Back 6

Diplococci (pairs)
Streptococci (chains)
Tetracocci (tetrads)
Staphylococci (clusters)
Sarcinae (cuboidal packets)

Front 7

Types of dyes: (4)

Back 7

Types of dyes:
 Cationic
 Anionic
 Fat Soluble
 Insoluble Dyes

Front 8

Cationic (____ dyes, positively charged chromophore) – 2 examples

Anionic (____ dyes, negatively charged chromophore) – 3 examples

Back 8

basic ; Methylene Blue, Crystal Violet

acidic ; Acid fuschin, Congo Red, Nigrosin

Front 9

Fat Soluble (__ _____): ____ _____ stains granules of Poly-B-OH-butyric acid

Insoluble Dyes (water insoluble): ___ ___ (colloid suspension of _____ particles)

Back 9

no charge ; Sudan Black

India Ink ; carbon

Front 10

Gram stain – A ______ stain procedure that causes cells to stain differently based on characteristics of their cell wall. Gram-positive microorganisms have a higher ________ and lower ____ content than gram-negative microorganisms.

Back 10

differential ; peptidoglycan ; lipid

Front 11

What is the decolorizer in a gram stain?

Back 11

Ethanol

Front 12

Acid Fast Stain - A _______ stain procedure that causes cells to stain differently based on characteristics of their cell wall. Acid Fast microorganisms have a high ___ content in their walls, which requires the use of steam to allow dye to penetrate the cell. Cells are steamed in the presence of _____ ______ and decolorized with acid alcohol. Cells which are “acid fast” (microorganisms have a high wax content in their walls) will not decolorize and remain ___, while non acid fast organism will readily lose their stain and become colorless. These cells are then counterstained with _________ _____.

Back 12

differential ; wax ; carbol fuschin ; red ; Methylene blue

Front 13

Two genera of Acid Fast Organisms (All other genera are Non-Acid Fast):

Back 13

Mycobacterium – Do not gram stain well if mature because of high wax content within walls, if young appear as gram + tapered rods that sometimes fragment

Nocardia

Front 14

Two important species of Mycobacterium:

Back 14

tuberculosis and leprae

Front 15

Some microorganisms produce heat and chemical resistant structures called endospores or free spores. To stain the spores the cells must be steamed to allow for the dye (______ ____) to enter the spores. Once the spores are stained, all other microorganisms and vegetative cells can easily be decolorized with water, while the free spores and endospores retain the malachite green. The other microorganisms and vegetative cells are then counterstained with _____.

Back 15

malachite green ; Safranin

Front 16

Three genera of Spore forming organisms

Back 16

Bacillus – Aerobic, gram + rod
Clostridium – Anaerobic gram + rod
Sporsarcinae – Cocci