Chapter 3 Vocab

Question 1

culture

Answer 1

the visible accumulation of microorganisms in or on a nutrient medium. Also, the propagation of microorganisms with various media

Question 2

medium

Answer 2

a nutrient used to grow organisms outside of their natural habitats

Question 3

inoculation

Answer 3

the implantation of microorganisms into or upon culture media

Question 4

isolation

Answer 4

the separation of microbial cells by serial dilution or mechanical dispersion on solid media to create discrete colonies

Question 5

colony

Answer 5

a macroscopic cluster of cells appearing on a solid medium, each arising from the multiplication of a single cell

Question 6

liquid media

Answer 6

type of culture media used to cultivate and maintain microorganisms

Question 7

broths

Answer 7

any number of liquid media

Question 8

semisolid media

Answer 8

nutrient media with a firmness midway between that of a broth ( a liquid medium) and an ordinary solid medium; motility media

Question 9

agar

Answer 9

a polysaccharide found in seaweed and commonly used to prepare solid culture media

Question 10

synthetic media

Answer 10

medium composed of pure chemical compounds

Question 11

non-synthetic media

Answer 11

Media containing imprecise composition of ingredients

Question 12

general purpose media

Answer 12

media that has a multiple effect, i.e. it can be used as a selective, deferential or a resuscitation media

Question 13

enriched media (medium)

Answer 13

a nutrient medium supplemented with blood, serum, or some growth factor to promote the multiplication of fastidious microorganisms

Question 14

growth factors

Answer 14

an organic compound such as a vitamin or amino acid that must be provided in the diet to facilitate growth . essential nutrient

Question 15

fastidious

Answer 15

requiring strict, narrow nutritional or environmental conditions for growth. Said of bacteria

Question 16

selective medium

Answer 16

growth of only selected microorganisms

Question 17

differential medium

Answer 17

a single substrate that discriminates between groups of microorganisms on the basis of differences in their appearance due to different chemical reactions

Question 18

incubated

Answer 18

to isolate a sample culture in a temperature-controlled environment to encourage growth

Question 19

pure culture

Answer 19

a container growing a single species of microbe whose identity is known

Question 20

axenic

Answer 20

a sterile state such as pure culture. an axenic animal is born and raised in a germ-free environment

Question 21

subculture

Answer 21

to make a second-generation culture from a well-established colony of organisms

Question 22

mixed culture

Answer 22

a container growing two or more microbes of different species or microbes

Question 23

streak plate method

Answer 23

isolation procedure used to isolate bacteria from a mixed bacterial culture. It is a dilution technique in which a bacterial sample is streaked over the agar surface in quadrants so that bacterial cell density gets diluted and individual cells spread over the agar surface

Question 24

spread plate method

Answer 24

The spread plate method is a microbiological laboratory technique for isolating and counting the viable microorganisms present in a liquid sample by spreading a certain volume of the sample over an appropriate solidified culture media

Question 25

pour plate method

Answer 25

pour plate method A method of inoculating a solid nutrient medium by mixing bacteria in the melted medium and pouring the medium into a Petri dish to solidify

Question 26

contaminated culture

Answer 26

a culture with an impurity. a culture into which unknown microbes have been introduced is contaminated

Question 27

microscopy

Answer 27

science that studies structure, magnification, lenses, and techniques related to use of a microscope

Question 28

magnification

Answer 28

total magnification The magnification of a microscopic specimen, determined by multiplying the ocular lens magnification by the objective lens magnification

Question 29

resolving power

Answer 29

the capacity of a microscope lens system to accurately distinguish between two separate entities that lie close to each other; also called resolution

Question 30

resolution

Answer 30

the capacity of a microscope lens system to accurately distinguish between two separate entities that lie close to each other

Question 31

refraction

Answer 31

in optics, the bending of light as it passes from one medium to another with a different index of refraction

Question 32

numerical aperture

Answer 32

in microscopy, a measure of the light passing from the object and into the objective to maximize optical clarity and resolution

Question 33

fluorescence

Answer 33

the property possessed by certain minerals and dyes to emit visible light when excited by ultraviolet radiation. one application is to combine a __________ dye with a specific antibody to detect the presence of and unknown antigen

Question 34

dark-field microscopy

Answer 34

produces an image with a dark background.  Dark field microscopy is a technique used to observe unstained samples causing them to appear brightly lit against a dark, almost purely black, background.  used to examine live microorganisms that are not visible with light microscope and cannot stained, or distorted by staining and cannot be identified

Question 35

phase-contrast microscopy

Answer 35

It reveals many cellular structures that are invisible with a bright-field microscope, as exemplified in the figure. These structures were made visible to earlier microscopists by staining, but this required additional preparation and death of the cells.

Question 36

interference microscopy

Answer 36

a method of investigating the structure of various, mainly biological, objects and of measuring their dry weight, thickness, and refractive index

Question 37

bright-field microscopy

Answer 37

compound light microscope, which illuminates the background against a stained specimen. It is commonly used in the practical labs to study organisms’ behaviour and characteristics like size, shape and arrangement.

Question 38

scanning electron microscope

Answer 38

is a type of electron microscope that scans surfaces of microorganisms that uses a beam of electrons moving at low energy to focus and scan specimens.

Question 39

transmission electron microscope

Answer 39

This unit describes preparation techniques for examining particulate samples as well as samples presenting more complex ultrastructural considerations that require analysis in thin sections.

Question 40

basic and acidic dyes

Answer 40

In staining during microscopic examination for diagnosis or research, acid dyes are used to color basic tissue proteins. In contrast, basic dyes are used to stain cell nuclei and some other acidic components of tissues.

Question 41

positive and negative staining

Answer 41

Stains are salts composed of positive and negative ions. One of these ions is colored and called the chromophore. Basic dyes consist of the positive ion that stains negatively charged structures

Question 42

simple stains

Answer 42

type of positive staining technique that uses a single dye to add color to cells so that they are easier to see. this technique tends to color all cells the same color

Question 43

differential stains

Answer 43

a technique that utilizes two dyes to distinguish between microbial groups or cell parts by color reaction

Question 44

gram staining

Answer 44

a differential stain for bacteria useful in identification and taxonomy. Positive: They will appear purple from crystal violet-mordant retention. Negative: appear red after loss of crystal violet and absorbance of the safranin counterstain

Question 45

acid-fast staining

Answer 45

the property of mycobacteria to retain carbol fuchsin even in the presence of acid alcohol. used to diagnose tuberculosis

Question 46

special staining

Answer 46

technique is used to examine bacterial spores