Deck 7: Growth and Culturing of Bacteria

Question 1

Most human pathogens are _____.

A)psychrophiles
B)mesophiles
C)thermophiles
D)acidophiles

Answer 1

B

Question 2

Capnophiles grow best under conditions of _____.

A)high carbon dioxide
B)low carbon dioxide
C)high osmotic pressure
D)low osmotic pressure

Answer 2

A

Question 3

A bacterial population grows most rapidly during ________ phase.

A)lag
B)log
C)stationary
D)death

Answer 3

B

Question 4

Most bacteria reproduce by:

A)sexual reproduction
B)binary fission
C)budding
D)homologous recombination

Question 5

A bacterial culture can be kept in the log phase of growth indefinitely with the help of a/an:

A)incubator
B)chemostat
C)spectrophotometer
D)colony counter

Question 6

An obligate psychrophile would produce a turbid culture at ________ degrees Celsius.

A)15
B)30
C)45
D)60

Question 7

Bacterial growth in colonies on agar plates _____.

A)have all phases of growth occurring simultaneously somewhere in the colony
B)most growth occurs at the center of the colony
C)involves budding of small new colonies from the surface of an existing colony
D)have lag phase cells in the center of the colony,surrounded by a ring of cells in exponential phase

Question 8

Turbidity in a bacterial culture can be measured using a/an:

A)incubator
B)colony county
C)spectrophotometer
D)chemostat

Question 9

Which of the following is most likely to have evolved to live in the deep layers of mud,where there is a complete lack of free oxygen

A)Obligate aerobe
B)Obligate anaerobe
C)Facultative anaerobe
D)Aerotolerant anaerobe

Question 10

Microbial growth:

A)refers to the increase in the size of a microbial cell.
B)refers to the increase in the frequency of cell division.
C)in a single generation time leads to double the cell size.
D)in a single generation time leads to double the number of microbes.

Question 11

Serial dilutions are used to:

A)slow down the growth of microbes
B)speed up the growth of microbes
C)obtain bacterial cultures at several different concentrations
D)form bacterial colonies

Question 12

Acidophiles would be expected to grow best at a pH of _____.

A)3
B)6
C)9
D)12

Question 13

In the stationary phase of bacterial growth:

A)the number of newly generated cells is greater than the number of dying cells
B)the number of newly generated cells is less than the number of dying cells
C)the number of newly generated cells is the same as the number of dying cells
D)none of these

Question 14

Which of the following is not one of the phases of bacterial growth

A)Lag phase
B)Stationary phase
C)Doubling phase
D)Log phase

Question 15

Which type of cell will generally shift to aerobic metabolism when oxygen is available but will carry on fermentation otherwise

A)aerotolerant anaerobes
B)facultative anaerobes
C)obligate anaerobes
D)obligate aerobes

Question 16

Most bacteria:

A)exhibit synchronous growth under natural conditions
B)divide when a small new cell develops from the surface of an existing cell
C)do not immediately increase in number when placed in a culture
D)immediately begin to divide when placed in a culture

Question 17

The type of cell reproduction in which a small,new cell develops from the surface of an existing cell and then separates from the parent cell is known as ________ and is the normal mode of replication in _____ .

A)binary fission,bacteria
B)binary fission,yeast
C)budding,bacteria
D)budding,yeast

Question 18

When a bacterial cell divides into two new cells,the new cells are called:

A)daughter cells
B)sister cells
C)son cells
D)father cells

Question 19

Which of the following counting techniques does not differentiate between live and dead bacterial cells in a culture

A)Serial dilution
B)Spread plate
C)Pour plate
D)Direct microscopic count

Question 20

Which of the following bacterial counting techniques relies on a statistical estimate to determine the of bacteria in a culture

A)Serial dilution
B)Standard plate count
C)Spread plate
D)Most probable number

Question 21

All of the following are ways microorganisms adapt to limited nutrients except:

A)synthesize increased amount of enzymes for uptake and metabolism of limited nutrients
B)form metabolically active highly resistant endospores
C)synthesize enzymes needed to use a different nutrient source
D)adjust the rate at which they metabolize nutrients

Question 22

Sporulation usually occurs in response to a/an _____.

A)decrease in the level of carbon or nitrogen
B)increase in temperature
C)decrease in the amount of water
D)increase in ultraviolet radiation

Question 23

The pour plate method of isolating pure cultures _____.

A)relies on the fact that liquid agar will solidify as it cools
B)is useful for growing microaerophiles
C)results in some organisms growing embedded in the agar
D)all of these

Question 24

Exoenzymes:

A)produced by gram positive rods act in the medium around the organism
B)are released by the golgi apparatus into the cytoplasm where they act
C)produced by gram negative rods act in the periplasmic space
D)two of these

Question 25

Starch would be broken down to maltose by which of the following exoenzymes

A)gelatinase
B)amylase
C)caseinase
D)lipase

Question 26

A culture that contains only a single species of organism is known as a _____.

A)pure culture
B)Koch culture
C)mixed culture
D)contaminated culture

Question 27

A decrease in the amount of nitrogen to a culture of Clostridium botulinum would induce _____.

A)activation
B)germination
C)sporulation
D)outgrowth

Question 28

Which of the following statements about bacterial growth is false

A)Agar is used as a solidifying agent in some types of media.
B)Bacteria growing in a liquid culture will generate colonies.
C)A turbid culture is indicative of bacterial growth.
D)Each bacterium plated will represent a colony-forming unit.

Question 29

Which of the following is not a stage in endospores returning to the vegetative state

A)Traumatic agent such as low pH or heat damages the coat.
B)Outgrowth occurs in a medium with adequate nutrients.
C)Divisions of the endospores early in their development.
D)Water and nutrients penetrates damaged coat.

Question 30

The toxic effects of the byproducts of oxygen metabolism are reduced by which of the following

A)Catalase
B)Superoxide dismutase
C)Lactase
D)Two of these

Question 31

Which of the following does not contribute to endospore resistance to unfavorable conditions

A)Dipicolinic acid and calcium ions in the core
B)Cortex
C)Spore coat
D)Germination proper

Question 32

Endospores are:

A)metabolically active
B)reproductive structures
C)found mostly in Gram negative organisms
D)protective structures

Question 33

Where would you expect to find a barophile

A)At the bottom of the ocean
B)In unpasteurized milk
C)In the large intestine
D)In sewage

Question 34

When cells are placed in a hypertonic environment they will undergo ________ .

A)lysis
B)no change in size
C)swelling of the cell which is contained by the cell wall
D)plasmolysis

Question 35

Sporulation occurs in:

A)Clostridium
B)Staphylocoocus
C)Klebsiella
D)Citrobacter

Question 36

Within a bacterial endospore,the spore is most closely surrounded by the _____.

A)spore membrane
B)cortex
C)cell membrane
D)spore coat

Question 37

Halophiles require an environment with a high concentration of ________ for optimal growth.

A)sugar
B)alcohol
C)salt
D)phosphorous

Question 38

The streak plate method produces pure cultures by separating individual bacterial cells from one another by _____.

A)dragging them across a solid surface
B)dispersing them in liquid media
C)killing off those cells that are not able to survive in hot agar
D)embedding some cells in the agar so that they are exposed to lower concentrations of oxygen

Question 39

Which of the following is considered a trace element

A)carbon
B)zinc
C)sulphur
D)phosphorous

Question 40

Organisms with special nutritional needs are said to be _____.

A)barophiles
B)fastidious
C)aerobes
D)none of these

Question 41

______ techniques must be strictly adhered to prevent the accidental contamination of stock cultures.

A)Germination
B)Selective
C)Differential
D)Aseptic

Question 42

A candle jar would be used for growing:

A)Gram negative organisms
B)fastidious organisms
C)thermophiles
D)microaerophiles

Question 43

Microbes that live in this environment actively transport _____ out of their cells.

A)potassium
B)oxygen
C)sodium
D)nitrogen

Question 44

Sabourard's agar has a low pH which encourages the growth of molds and discourages the growth of bacteria.Sabourard's agar could best be described as being:

A)selective
B)differential
C)complex
D)enriched

Question 45

Chocolate agar:

A)contains blood
B)is used exclusively for stock cultures
C)is nutrient poor
D)is a selective agar plate

Question 46

A media on which Gram positive organism turn green and Gram negative organisms turn blue would be _____.

A)selective
B)differential
C)complex
D)enriched

Question 47

A growth medium consisting of only known amounts of water,magnesium,calcium chloride,potassium and glucose would be considered:

A)a defined synthetic medium
B)a complex medium
C)a chemically nondefined medium
D)two of these

Question 48

Microaerophiles:

A)grow best when the environment has a small amount of carbon dioxide.
B)grow best when the environment has a small amount of free oxygen.
C)need a high concentration of carbon dioxide.
D)need a high concentration of oxygen.

Question 49

Which of the following statements about liquid media and agar is false

A)Both chocolate agar and blood agar contain blood.
B)Stock cultures are never directly used for laboratory studies.
C)A differential media will allow some bacteria to grow and stop the growth of others.
D)A selective media will suppress the growth of some microbes.

Question 50

This phase decreases at a logarithmic rate.

A)A
B)B
C)C
D)D

Question 51

Bacteria that ferment lactose grow as red colonies on MacConkey's agar while those that do not ferment lactose are transparent.MacConkey's agar can best be described as being:

A)selective
B)differential
C)complex
D)enriched

Question 52

A living,growing culture whose purpose is to maintain a pure culture of an organism indefinitely is a _____.

A)colony
B)stock culture
C)sporulating culture
D)broth culture

Question 53

Nonculturable organisms:

A)are rare.
B)can be identified based on their DNA.
C)can only be seen on selective agar plates.
D)have defined generation times.

Question 54

A growth medium consisting of only water,glucose and beef extract would be considered _____.

A)a defined synthetic medium
B)a complex medium
C)a chemically defined medium
D)two of these

Question 55

During this phase,organisms produce large amounts of ATP.

A)A
B)B
C)C
D)D