Question 1

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

Accepted Answer

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 
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 A

Question 2

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?

Accepted Answer

Sporulation is the formation of endospores which are not metabolically active and are very resistant to extreme conditions and stress. The endospore cannot divide but can wake up when conditions for growth are restored. Endospores are generally triggered during stationary phase in response to environmental,metabolic and cell cycle signals.
It would be harmful for the whole population to sporulate if the conditions changed rapidly or not predictably,if for example within those eight hours the nutrients where restored then the whole population would be unable to respond as they would still be sporulating. Also if there were a false alarm it would also be harmful for the whole population to sporulate.
An advantage to continuously forming spores are mainly in rapidly changing or unpredictable conditions as there will always be a safety net (spores)already formed. A disadvantage to continuously forming spores is that spores are not dividing,therefore they do not contribute to increasing the size of the bacteria population (e.g.,fitness)and could be seen as diverted resource.

Question 3

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:

Accepted Answer

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

Question 4

Endospores are:

Accepted Answer

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

Question 5

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 _____ .

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

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

Accepted Answer

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

Question 8

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

Accepted Answer

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

Question 9

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:

Accepted Answer

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

Question 10

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

Accepted Answer

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

Question 11

A candle jar would be used for growing:

Accepted Answer

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

Question 12

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

Accepted Answer

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

Question 13

Bacterial growth in colonies on agar plates _____.

Accepted Answer

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 
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 14

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

Accepted Answer

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

Question 15

Sporulation usually occurs in response to a/an _____.

Accepted Answer

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 
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 16

Chocolate agar:

Accepted Answer

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

Question 17

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

Accepted Answer

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. 
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 18

Nonculturable organisms:

Accepted Answer

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. 
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 19

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

Accepted Answer

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

Question 20

Microbial growth:

Accepted Answer

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. 
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.

Exam 6: Growth and Culturing of Bacteria

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

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:

Endospores are:

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 _____ .

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

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

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

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

A candle jar would be used for growing:

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

Bacterial growth in colonies on agar plates _____.

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

Sporulation usually occurs in response to a/an _____.

Chocolate agar:

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

Nonculturable organisms:

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

Microbial growth:

Scope and History of Microbiology

Fundamentals of Chemistry

Microscopy and Staining

Characteristics of Prokaryotic and Eukaryotic Cells

Essential Concepts of Metabolism

Microbial Genetics

Gene Transfer and Genetic Engineering

An Introduction to Taxonomy: the Bacteria

Viruses

Eukaryotic Microorganisms and Parasites

Sterilization and Disinfection

Antimicrobial Therapy

Host-Microbe Relationships and Disease Processes

Epidemiology and Nosocomial Infections

Innate Host Defenses

Immunology I: Basic Principles of Adaptive Immunity and Immunization

Immunology Ii: Immunological Disorders and Tests

Diseases of the Skin and Eyes; Wounds and Bites

Urogenital and Sexually Transmitted Diseases

Diseases of the Respiratory System

Oral and Gastrointestinal Diseases

Cardiovascular, lymphatic and Systemic Disease

Diseases of the Nervous System

Environmental Microbiology

Applied Microbiology

Filters

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 _ .