Question 1

Which of the following is the best technique for counting only viable cells?

Accepted Answer

A)  direct microscopic count 
B)  spread plate 
C)  spectrophotometer 
D)  chemostat 
E)  dry weight measurements 
A)  direct microscopic count 
B)  spread plate 
C)  spectrophotometer 
D)  chemostat 
E)  dry weight measurements

Question 2

During which stage of bacterial growth is the culture growing exponentially?

Accepted Answer

A)  lag phase 
B)  log phase 
C)  growth phase 
D)  stationary phase 
E)  death phase 
A)  lag phase 
B)  log phase 
C)  growth phase 
D)  stationary phase 
E)  death phase

Question 3

The primary goal of biofilms is thought to be

Accepted Answer

A)  microbial communication. 
B)  cell differentiation. 
C)  to stay where food is abundant. 
D)  to cause infection. 
E)  environmental degradation. 
A)  microbial communication. 
B)  cell differentiation. 
C)  to stay where food is abundant. 
D)  to cause infection. 
E)  environmental degradation.

Question 4

The figure below represents what type of differentiation?

Accepted Answer

A)  heterocyst formation 
B)  budding 
C)  sporulation 
D)  fruiting body formation 
E)  filamentation 
A)  heterocyst formation 
B)  budding 
C)  sporulation 
D)  fruiting body formation 
E)  filamentation

Question 5

Quorum sensing is triggered in biofilms when

Accepted Answer

A)  they form microcolonies. 
B)  they are dispersing. 
C)  antibiotics are applied to them. 
D)  the population reaches a certain number. 
E)  cells attach to a surface. 
A)  they form microcolonies. 
B)  they are dispersing. 
C)  antibiotics are applied to them. 
D)  the population reaches a certain number. 
E)  cells attach to a surface.

Question 6

Cyanobacterial heterocysts function to fix atmospheric

Accepted Answer

A)  hydrogen sulfide. 
B)  ammonia. 
C)  oxygen. 
D)  carbon dioxide. 
E)  nitrogen. 
A)  hydrogen sulfide. 
B)  ammonia. 
C)  oxygen. 
D)  carbon dioxide. 
E)  nitrogen.

Question 7

Why do some members of a biofilm community live deep within the biofilm?

Accepted Answer

A)  They are not flagellated. 
B)  They produce fewer exopolysaccharides. 
C)  They were the first organisms to initiate attachment. 
D)  Antibiotics do not penetrate deep into biofilms. 
E)  Oxygen does not penetrate deep into biofilms. 
A)  They are not flagellated. 
B)  They produce fewer exopolysaccharides. 
C)  They were the first organisms to initiate attachment. 
D)  Antibiotics do not penetrate deep into biofilms. 
E)  Oxygen does not penetrate deep into biofilms.

Question 8

How does Anabaena overcome the challenge of performing both photosynthesis and nitrogen fixation?

Accepted Answer

The autotrophic cyanobacteria Anabaena c

Question 9

Bacteria divide at a constant time interval called the

Accepted Answer

A)  generation time. 
B)  growth time. 
C)  growth rate. 
D)  exponential rate. 
E)  log phase. 
A)  generation time. 
B)  growth time. 
C)  growth rate. 
D)  exponential rate. 
E)  log phase.

Question 10

A problem with ________ of cell number is that dead cells also scatter light.

Accepted Answer

A)  direct microscopic counts 
B)  viable counts 
C)  spread plate counts 
D)  pour plate counts 
E)  optical density measurements 
A)  direct microscopic counts 
B)  viable counts 
C)  spread plate counts 
D)  pour plate counts 
E)  optical density measurements

Question 11

Why does a microbe's growth rate in its natural environment vary greatly from that in the laboratory? Give at least two reasons for this.

Accepted Answer

Answers will vary. A laboratory setting

Question 12

Why is iron so often a limiting nutrient, when it seems to be so abundant in the environment, and how can organisms overcome this problem?

Accepted Answer

Iron is usually not free in nature but l

Question 13

Which of the following can consume glucose and, in the absence of oxygen, break it down into ethanol and carbon dioxide gas?

Accepted Answer

A)  E. coli 
B)  phototrophs 
C)  yeast 
D)  archaea 
E)  nitrogen fixers 
A)  E. coli 
B)  phototrophs 
C)  yeast 
D)  archaea 
E)  nitrogen fixers

Question 14

A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a quiche with 4 E. coli cells when he uses his finger to test whether it is done. By the time you purchase the quiche, there are 128 E. coli cells in it. How many generations did the cells go through?

Accepted Answer

A)  4 
B)  5 
C)  8 
D)  32 
E)  64 
A)  4 
B)  5 
C)  8 
D)  32 
E)  64

Question 15

During biofilm formation, as more and more cells bind to the surface, they begin sending signals to each other in a process called

Accepted Answer

A)  quorum sensing. 
B)  homoserine lactone sensing. 
C)  siderophore-iron acquisition. 
D)  polysaccharides uptake. 
E)  density sensing. 
A)  quorum sensing. 
B)  homoserine lactone sensing. 
C)  siderophore-iron acquisition. 
D)  polysaccharides uptake. 
E)  density sensing.

Question 16

Define the terms "viable" and "viable but unculturable." Why are so many environmental organisms believed to be viable but unculturable?

Accepted Answer

Viable means that the organism can repli

Question 17

The majority of nitrogen in soil and marine environments is fixed by

Accepted Answer

A)  free-living bacteria and archaea. 
B)  symbionts. 
C)  E. coli. 
D)  biofilm organisms. 
E)  UV light. 
A)  free-living bacteria and archaea. 
B)  symbionts. 
C)  E. coli. 
D)  biofilm organisms. 
E)  UV light.

Question 18

When the intracellular iron concentration is low, iron-scavenging molecules called ________ are produced.

Accepted Answer

A)  siderophores 
B)  endospores 
C)  heterocysts 
D)  mycelia 
E)  quorum sensors 
A)  siderophores 
B)  endospores 
C)  heterocysts 
D)  mycelia 
E)  quorum sensors

Question 19

Growth of most microorganisms occurs by

Accepted Answer

A)  budding. 
B)  binary fission. 
C)  replication. 
D)  conjugation. 
E)  transformation. 
A)  budding. 
B)  binary fission. 
C)  replication. 
D)  conjugation. 
E)  transformation.

Question 20

Why can't most organisms use the nitrogen gas that is so prevalent in the atmosphere? How do these organisms acquire a usable form of nitrogen?

Accepted Answer

Nitrogen gas has triple bonds holding th

Exam 4: Bacterial Culture, Growth, and Development

Which of the following is the best technique for counting only viable cells?

During which stage of bacterial growth is the culture growing exponentially?

The primary goal of biofilms is thought to be

The figure below represents what type of differentiation?

Quorum sensing is triggered in biofilms when

Cyanobacterial heterocysts function to fix atmospheric

Why do some members of a biofilm community live deep within the biofilm?

How does Anabaena overcome the challenge of performing both photosynthesis and nitrogen fixation?

Bacteria divide at a constant time interval called the

A problem with ________ of cell number is that dead cells also scatter light.

Why does a microbe's growth rate in its natural environment vary greatly from that in the laboratory? Give at least two reasons for this.

Why is iron so often a limiting nutrient, when it seems to be so abundant in the environment, and how can organisms overcome this problem?

Which of the following can consume glucose and, in the absence of oxygen, break it down into ethanol and carbon dioxide gas?

A cafeteria worker who fails to wash his hands thoroughly and fails to wear gloves inoculates a quiche with 4 E. coli cells when he uses his finger to test whether it is done. By the time you purchase the quiche, there are 128 E. coli cells in it. How many generations did the cells go through?

During biofilm formation, as more and more cells bind to the surface, they begin sending signals to each other in a process called

Define the terms "viable" and "viable but unculturable." Why are so many environmental organisms believed to be viable but unculturable?

The majority of nitrogen in soil and marine environments is fixed by

When the intracellular iron concentration is low, iron-scavenging molecules called ________ are produced.

Growth of most microorganisms occurs by

Why can't most organisms use the nitrogen gas that is so prevalent in the atmosphere? How do these organisms acquire a usable form of nitrogen?

Microbial Life: Origin and Discovery

Observing the Microbial Cell

Cell Structure and Function

Environmental Influences and Control of Microbial Growth

Viruses

Genomes and Chromosomes

Transcription, Translation, and Bioinformatics

Gene Transfer, Mutations, and Genome Evolution

Molecular Regulation

Viral Molecular Biology

Biotechniques and Synthetic Biology

Energetics and Catabolism

Electron Flow in Organotrophy, Lithotrophy, and Phototrophy

Biosynthesis

Food and Industrial Microbiology

Origins and Evolution

Bacterial Diversity

Archaeal Diversity

Eukaryotic Diversity

Microbial Ecology

Microbes in Global Elemental Cycles

Human Microbiota and Innate Immunity

The Adaptive Immune Response

Microbial Pathogenesis

Microbial Diseases

Antimicrobial Therapy

Clinical Microbiology and Epidemiology

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