chapter 2 objectives

Question 1

5 I’s of microbiology

Answer 1

inoculation, incubation, isolation, inspection, identification

Question 2

inoculation

Answer 2

bringing microorganisms into a culture media

Question 3

incubation

Answer 3

introducing microorganisms to a temperature controlled chamber to encourage the multiplication of microbes

Question 4

isolation

Answer 4

once cultures have grown, they may need to be re-inoculated and re-incubated so the separate species are obtained

Question 5

inspection

Answer 5

the act of observing microscopically and macroscopically and possibly staining as well

Question 6

identification

Answer 6

the identity of an isolated microbiome is identified

Question 7

3 physicals states of culture media

Answer 7

semisolid, solid, transport

Question 8

selective vs. differential media

Answer 8

selective: designed to promote growth of certain organisms and suppress others
differential: multiple types grown but visibly different

Question 9

best method for colony isolation

Answer 9

streak plating

Question 10

3 pioneers of microscopy

Answer 10

Galileo (created microscope by modifying telescope), Hooke (discovered microorganisms with the compound microscope), and Leeuwenhoek (found “animals” in drops of water and “animalcules” from teeth)

Question 11

resolution

Answer 11

ability of an optical system to differentiate between two adjacent objects/points from each other

Question 12

contrast

Answer 12

the difference in light intensity of the specimen relative to its background

Question 13

real image

Answer 13

the image formed by the objective

Question 14

virtual image

Answer 14

formed by the image projected up through the microscope body to the eyepiece where the ocular lens forms the second image

Question 15

purpose of oil immersion lens

Answer 15

increase resolution when increasing magnification objective

Question 16

3 elements of good microscopy

Answer 16

magnification, resolution, and contrast.

Question 17

3 types of light microscopes

Answer 17

bright-field (light through specimen)
dark-field (blocks all light)
phase contrast (light waves)

Question 18

2 types of uv microscopes

Answer 18

fluorescence (ultraviolet light)
confocal (high resolution with fluorescent probes)

Question 19

2 types of electron microscopes

Answer 19

transmission electron (beam of electrons
scanning electron (focused electron beam)

Question 20

simple stain example

Answer 20

methylene blue (flooding with basic dye)

Question 21

differential stain example

Answer 21

gram staining (2 different dyes)

Question 22

special stain example

Answer 22

acid staining (target a specific bacteria)

Question 23

steps of gram stain

Answer 23

1. stain microorganism with crystal violet (positive and negative appear violet)
2. add iodine which will slightly change color on both to blue purple
3. alcohol wipe is applied to both grams because gram positive keeps its stain whereas gram negative looses it
4. add safranine where gram positive remains purple and gram negative turns pink/red

Question 24

difference between cell wall of gram negative/gram positive

Answer 24

gram negative has thinner 2D peptidoglycan layer with no teichoic acid
gram positive has thicker peptidoglycan layer with teichoic acid

Question 25

color of gram positive and gram negative organism

Answer 25

gram positive: purple/blue (thicker peptidoglycan layers in cell walls)
gram negative: pink/red (thinner peptidoglycan layers in cell walls)

Question 26

acid fast stain use

Answer 26

Used to identify bacteria that have a waxy (lipid) layer

Question 27

spore stain use

Answer 27

Used to detect endospores, typically found in bacteria

Question 28

capsule stain use

Answer 28

Used to visualize the presence of capsules surrounding certain bacteria, aiding in their identification and understanding their virulence

Question 29

flagella stain use

Answer 29

Used to highlight the presence and arrangement of flagella, aiding in the characterization of motile bacteria

Question 30

fluorescense stain use

Answer 30

Utilized to detect specific molecules or structures within cells using fluorescent dyes.