Ch.5 Interactive glossary

Question 1

A bacteriological medium that binds oxygen gas from the atmosphere and creates an environment suitable for anaerobic growth.

Answer 1

Thioglycollate broth

Question 2

A bacterium not inhibited by oxygen gas

Answer 2

Aerotolerant

Question 3

A chemically defined medium in which the nature and quantity of each component is identified.

Answer 3

Synthetic medium

Question 4

A chemically undefined medium in which the nature and quantity of each component has not been identified.

Answer 4

Complex medium

Question 5

A common bacteriological growth medium consisting of beef extract, peptone, and water.

Answer 5

Nutrient broth

Question 6

A common bacteriological growth medium consisting of beef extract, peptone, water, and agar.

Answer 6

Nutrient agar

Question 7

A differential growth medium that encourages the growth of staphylococci by containing a high percentage of salt, which is inhibitory to most other microorganisms.

Answer 7

Mannitol salt agar (MSA)

Question 8

A growth medium containing special nutrients to grow fastidious organisms.

Answer 8

Enriched medium

Question 9

A growth medium in which different species of microorganisms can be distinguished visually.

Answer 9

Differential medium

Question 10

A growth medium that contains ingredients to inhibit certain microorganisms while encouraging the growth of others.

Answer 10

Selective medium

Question 10

A laboratory test in which a statistical evaluation is used to estimate the number of bacterial cells in a sample of fluid; often employed in determinations of coliform bacteria in water.

Answer 10

Most probable number test

Question 11

A measure of the viable cells by counting the number of colonies on a plate; each colony presumably started from one viable cell.

Answer 11

Colony forming unit

Question 12

A microbe that grows best without salt but can tolerate low concentrations.

Answer 12

Halotolerant

Question 13

A microorganism that cannot grow in the presence of added sodium chloride.

Answer 13

Nonhalophile

Question 14

A microorganism that grows at acidic pHs below 4.

Answer 14

Acidophile

Question 15

A microorganism that lives under conditions of high atmospheric pressure.

Answer 15

Barophile

Question 16

A polysaccharide derived from marine seaweed that is used as a solidifying agent in many microbiological culture media.

Answer 16

Agar

Question 17

A portion of a bacterial growth curve encompassing the first few hours of the population’s history when no growth occurs.

Answer 17

Lag phase

Question 18

A procedure to estimate the number of cells in a sample dilution spread on an agar plate.

Answer 18

Standard plate count

Question 19

A process by which a mixed culture can be separated into pure colonies and the colonies isolated

Answer 19

Pour plate method

Question 20

A process by which a mixed culture can be streaked onto an agar plate and pure colonies isolated.

Answer 20

Streak plate method

Question 21

A prokaryote requiring relatively high concentrations of salt (NaCl).

Answer 21

Halophile

Question 22

A prokaryote that has an optimal growth temperature above 80 degrees C.

Answer 22

Hyperthermophile

Question 23

A prokaryote that is alive but cannot be cultured on any known growth medium.

Answer 23

VBNC

Question 24

An accumulation or colony of microorganisms of one species.

Answer 24

Pure culture

Question 25

An archaeal organism living at an extremely acidic pH.

Answer 25

Extreme acidophile

Question 26

An asexual process in bacterial and archaeal cells by which a cell divides to form two new cells while maintaining genetic constancy.

Answer 26

Binary fission

Question 27

An extremely resistant dormant cell produced by some gram-positive bacterial species.

Answer 27

Endospore

Question 27

An inward pinching of the cell envelope during binary fission.

Answer 27

Cytokinesis

Question 28

An organic substance that helps stabilize the proteins and DNA in a bacterial spore, thereby increasing spore resistance.

Answer 28

Diplocilinic acid

Question 29

An organism that cannot use oxygen gas for metabolism.

Answer 29

Obligate anaerobe

Question 30

An organism that does not require or cannot use oxygen gas for metabolism.

Answer 30

Anaerobe

Question 31

An organism that grows best in an oxygen-reduced environment.

Answer 31

Microaerophile

Question 31

An organism that grows in temperature ranges of 20 degrees C to 40 degrees C.

Answer 31

Mesophile

Question 32

An organism that lives at cold temperature ranges of 0 degrees C to 20 degrees C.

Answer 32

Psychrophile

Question 33

An organism that lives at high temperature ranges of 40 degrees C to 90 degrees C.

Answer 33

Thermophile

Question 34

An organism that lives in environments with high concentrations of salt.

Answer 34

Halophile

Question 35

An organism that requires oxygen gas for metabolism.

Answer 35

Obligate aerobe

Question 35

Each bacterial cell on an agar growth medium that divides to produce a discrete colony.

Answer 35

Colony forming unit (CFU)

Question 36

Estimation of the number of cells by observation with the light microscope.

Answer 36

Direct microscopic count

Question 37

One method to produce pure cultures in hardened agar.

Answer 37

Pour-plate isolation method

Question 38

One method to produce pure cultures on an agar plate.

Answer 38

Streak-plate isolation method

Question 39

Referring to a prokaryotic cell requiring low oxygen gas and a high concentration of carbon dioxide gas for metabolism.

Answer 39

Capnophilic

Question 40

Referring to an organism that does not require free oxygen.

Answer 40

Anaerobe

Question 41

Referring to an organism that grows best in an oxygen-reduced environment.

Answer 41

Microaerophile

Question 42

Referring to an organism that grows in the presence or absence of oxygen gas

Answer 42

Facultative

Question 43

Referring to microorganisms that grow at 0 degrees C but have a temperature optima of 20 degrees to 40 degrees C.

Answer 43

Psychrotolerant

Question 44

Referring to prokaryotes that are viable but not culturable.

Answer 44

Viable but not culturable (VBNC)

Question 45

The cloudiness of a broth culture due to bacterial growth.

Answer 45

Turbidity

Question 46

The final portion of a bacterial growth curve in which environmental factors overwhelm the population and induce death; also called death phase.

Answer 46

Decline phase

Question 47

The final portion of a bacterial growth curve in which environmental factors overwhelm the population and induce death; also called the decline phase.

Answer 47

Death phase

Question 48

The form of reproduction that maintains genetic constancy while increasing cell numbers.

Answer 48

Asexual reproduction

Question 49

The initial portion of a bacterial growth curve during which time the cells are preparing for reproduction (binary fission).

Answer 49

Lag phase

Question 50

The portion of a bacterial growth curve in which the reproductive and death rates of cells are equal.

Answer 50

Stationary phase

Question 51

The process of spore formation.

Answer 51

Sporulation

Question 52

The second portion of a bacterial growth curve, in which active growth leads to a rapid rise in cell number.

Answer 52

Logarithmic (log) phase

Question 53

The third portion of a bacterial growth curve in which the reproductive and death rates of cells are equal.

Answer 53

Stationary phase

Question 54

The time interval for a cell population to double in number

Answer 54

Generation time