Chapter 3 - Observing Microorganisms

Question 1

cm

Answer 1

Centimeter- 1/100 = 0.01 m (meters) = 10^-2

Question 2

mm

Answer 2

Milimeters - mili = 1/1000 = 0.001 m = 10^3 m

Question 3

“u”m

Answer 3

Micrometer - 1/1,000,000 = 0.000001 m = 10^-6

Question 4

nm

Answer 4

Nanometer - nano = 1/1,000,000,000 = 0.000000001 m = 10^-9

Question 5

Total magnification

Answer 5

Objective lens multiplied by ocular lens

Question 6

Resolution

Answer 6

The ability of the lenses to distinguish two points

Question 7

Greater resolution is given when provided what?

Answer 7

shorter wavelengths of light

Question 8

Objective lens

Answer 8

The lenses closest to the specimen

Question 9

Ocular lens

Answer 9

Eyepiece

Question 10

Brightfield illumination

Answer 10

Dark objects are visible against bright background, what is primarily done in lab course. Brightfield illumination shows internal structures and the outline of the transparent external covering or pellicle

Question 11

Fluorescence microscopy

Answer 11

Uses UV, shortwave wavelength , light. Fluorescence substances absorb UV light and emit longer wavelength ,visible, light

Question 12

Transmission electron microscopy

Answer 12

A beam of electrons passes through ultrathin sections of a specimen, then through and electromagnetic Lens, then focused on a projector lens. Specimens May be stainedwith heavy metal salts for contrast

Question 13

Scanning electron microscopy

Answer 13

And electron gun produces a beam of electrons That scans the surface of an entire specimen, secondary electrons emitted from the specimen produce a three-dimensional image.

Question 14

Staining

Answer 14

Coloring Microorganisms with a dye that emphasizes certain structures

Question 15

Mordant

Answer 15

Maybe used to hold the stain or coat the specimen to enlarge it. Example. Iodine

Question 16

Gram staining

Answer 16

Classifies bacteria into gram-positive or gram-negative

Question 17

Gram-positive

Answer 17

Bacteria that have thick peptidoglycan cell walls

Question 18

Gram-negative

Answer 18

Bacteria that have thin peptidoglycan cell walls and a layer of polysaccharides

Question 19

Acid-fast staining

Answer 19

Binds only to bacteria that have waxy material in their cell walls

Question 20

What are the two terms that are used to identify acid-fast stain?

Answer 20

Mycobacterium and nocardia

Question 21

endospore stain

Answer 21

Resistant, dormant structures inside some cells that cannot be stained by ordinary methods. Primary stain = Malachite green, usually with heat/Steam

Question 22

Capsule stain

Answer 22

Capsules are a gelatinous covering that do not accept most dyes, India ink or nigrosin contrast the background with the capsule