Deck 6: Growth and Culturing of Bacteria

Question 1

Turbidity in a bacterial culture can be measured using a/n

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

Answer 1

C

Question 2

Most bacteria reproduce by

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

Answer 2

B

Question 3

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

Answer 3

D

Question 4

Capnophiles grow best under conditions of

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

Question 5

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 6

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

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

Question 7

Which of the following counting techniques doesn't differentiate between live and dead bacterial cells in a culture?

A) serial dilution
B) spread plate
C) pour plate
D) direct microscopic count

Question 8

Which of the following types of organisms would be most likely to have evolved to live in the large intestine,where there is a complete lack of free oxygen?

A) obligate aerobe
B) obligate anaerobe
C) facultative anaerobe
D) aerotolerant anaerobe

Question 9

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 10

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 11

Acidophiles would be expected to grow best at a pH of

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

Question 12

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's time leads to double the cell size
D) in a single generation's time leads to double the number of microbes.

Question 13

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

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

Question 14

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 the above

Question 15

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 16

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 17

Most human pathogens are

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

Question 18

A bacterial population grows most rapidly during ________ phase.

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

Question 19

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 20

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

A) serial dilution
B) standard plate count
C) spread plate
D) most probable number

Question 21

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

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

Question 22

Sporulation occurs in

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

Question 23

Which of the following does not contribute to an endospore's resistance to unfavorable conditions?

A) dipicolinic acid and calcium ions in the core
B) cortex
C) spore coat
D) germination proper

Question 24

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 acetic acid
D) adjust the rate at which they metabolize nutrients

Question 25

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 the above

Question 26

Which of the following is considered a trace element?

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

Question 27

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 28

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 periplamic space
D) two of the above

Question 29

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 30

Sporulation usually occurs in response to

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

Question 31

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

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

Question 32

Which of the following is not a stage in endospores returning to 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 penetrate damaged coat

Question 33

Organisms with special nutritional needs are said to be

A) barophiles
B) fastidious
C) aerobes
D) none of the above

Question 34

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

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

Question 35

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

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

Question 36

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

A) catalase
B) superoxide dismutase
C) lactase
D) two of the above

Question 37

Endospores are

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

Question 38

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 39

Which of the following statements about bacteria 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 40

Where would you expect to find a barophile?

A) at the bottom of a lake
B) in unpasteurized milk
C) in the large intestine
D) in sewage

Question 41

A candle jar would be used for growing

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

Question 42

Chocolate agar

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

Question 43

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 the above

Question 44

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

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

Question 45

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 46

What is sporulation? What triggers sporulation? In bacteria that form endospores generally only a fraction of the total population sporulate and the process takes over eight hours. Explain why it would be harmful for the whole population to sporulate. Is it better to continuously form spores or wait to sporulate when conditions become unfavorable.

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 the above

Question 48

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

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

Question 49

Imagine NASA sends you a specimen from a planet that they believe contains an extraterrestial bacteria species. You are the microbiologist in charge of determining how to grow the extraterrestial bacteria. Many factors may affect the growth of this extraterrestial bacteria. Choose two and describe how you would test their effects.

Question 50

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

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

Question 51

Draw and label a standard growth curve. Describe each of the 4 phases. Why do you think bacteria don't continue to double indefinitely? You sample a culture that has reached the fourth phase after 2 days,can you think of one reason why the culture would begin to increase on day 4?

Question 52

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 53

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 54

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 55

Which of the following statements about 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