Question 1

The lag phase does NOT occur if all the cells in the culture are viable.

Accepted Answer

A) True 
 B)False  False

Question 2

To determine the specific growth rate of a bacterial population,it is essential to know

Accepted Answer

A) cell concentrations at varied time points. 
B) total number of cells in the population at varied time points. 
C) cell concentrations at varied time points or the generation time. 
D) turbidity measurements and the total number of cells in the population at varied time points. 
A) cell concentrations at varied time points. 
B) total number of cells in the population at varied time points. 
C) cell concentrations at varied time points or the generation time. 
D) turbidity measurements and the total number of cells in the population at varied time points. A

Question 3

A drug targeting ________ would NOT be an effective antibiotic.

Accepted Answer

A) ZipA 
B) FtsI 
C) MreB 
D) transpeptidation 
A) ZipA 
B) FtsI 
C) MreB 
D) transpeptidation C

Question 4

Heterotrophic bacteria will run out of organic growth substrates in batch cultures but chemostats can provide constant nutrient source for them to grow.Chemostats for photoautotrophic bacteria are not necessary to maintain them at a constant growth phase because a light can artificially be turned on constantly.

Accepted Answer

A) True 
 B)False

Question 5

Microbial growth is generally described as the increased number of cells rather than the expanding size of an individual microbial cell.

Accepted Answer

A) True 
 B)False

Question 6

The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two.

Accepted Answer

A) True 
 B)False

Question 7

A microbe growing in a refrigerator is likely

Accepted Answer

A) psychrophilic. 
B) mesophilic. 
C) psychrotolerant or psychrophilic. 
D) hyperthermophilic. 
A) psychrophilic. 
B) mesophilic. 
C) psychrotolerant or psychrophilic. 
D) hyperthermophilic.

Question 8

Counting chambers are used for estimating the number of cells present in a liquid culture.

Accepted Answer

A) True 
 B)False

Question 9

In both lag and stationary phase,there is no net increase or decrease in viable cells.

Accepted Answer

A) True 
 B)False

Question 10

Superoxide dismutase and catalase work together to convert superoxide into

Accepted Answer

A) peroxide. 
B) oxygen. 
C) ozone. 
D) water. 
A) peroxide. 
B) oxygen. 
C) ozone. 
D) water.

Question 11

Which is most abundant and active in divisome complexes?

Accepted Answer

A) FtsZ 
B) DNA replication forks 
C) MinCD 
D) MreB 
A) FtsZ 
B) DNA replication forks 
C) MinCD 
D) MreB

Question 12

Explain why a hyperthermophile is unlikely to be a human pathogen.

Accepted Answer

The human body's temperature i

Question 13

Enumerating cells in a biofilm is especially challenging for

Accepted Answer

A) microscopic direct counting. 
B) measuring turbidity. 
C) viability counts with spread plating. 
D) microscopic direct county,measuring turbidity,and viability counts with spread plating. 
A) microscopic direct counting. 
B) measuring turbidity. 
C) viability counts with spread plating. 
D) microscopic direct county,measuring turbidity,and viability counts with spread plating.

Question 14

One laboratory group repeated the same experiment described by others with the identical bacterial isolate and the same growth medium and conditions used but were unable to achieve the same O.D.at 600 nm.What is the LEAST likely cause for this discrepancy of turbidity measured?

Accepted Answer

A) One lab used 16 mm wide test tubes and the other used 18 mm wide test tubes. 
B) One lab subtracted the yellow color of the growth medium away from the final turbidity reported whereas the other lab used colorless water. 
C) One lab vigorously dispersed the biofilm-forming bacteria with vortexing and the other did not. 
D) The two labs varied with 1000 m elevation and did not consider the influence of pressure. 
A) One lab used 16 mm wide test tubes and the other used 18 mm wide test tubes. 
B) One lab subtracted the yellow color of the growth medium away from the final turbidity reported whereas the other lab used colorless water. 
C) One lab vigorously dispersed the biofilm-forming bacteria with vortexing and the other did not. 
D) The two labs varied with 1000 m elevation and did not consider the influence of pressure.

Question 15

Consider solution A (pH 6)and solution B (pH 9).Which of the following statements is CORRECT?

Accepted Answer

A) Solution A is 3 times more acidic than solution B. 
B) Solution A is 300 times more acidic than solution B. 
C) Solution B is 1,000 times more alkaline (basic)than solution A. 
D) Solution B is 3,000 times more alkaline (basic)than solution A. 
A) Solution A is 3 times more acidic than solution B. 
B) Solution A is 300 times more acidic than solution B. 
C) Solution B is 1,000 times more alkaline (basic)than solution A. 
D) Solution B is 3,000 times more alkaline (basic)than solution A.

Question 16

Organisms able to live in environments with high sugar concentrations are

Accepted Answer

A) halotolerant. 
B) osmophiles. 
C) xerophiles. 
D) anaerobic fermenting bacteria. 
A) halotolerant. 
B) osmophiles. 
C) xerophiles. 
D) anaerobic fermenting bacteria.

Question 17

An agar plate for counting colonies and maximizing statistical validity should ideally contain

Accepted Answer

A) 1 to 100 colonies. 
B) 50 to 100 colonies. 
C) 30 to 300 colonies. 
D) 100 to 1000 colonies. 
A) 1 to 100 colonies. 
B) 50 to 100 colonies. 
C) 30 to 300 colonies. 
D) 100 to 1000 colonies.

Question 18

Which of the following methods to enumerate cells often requires specialized staining to observe non-pigmented bacteria?

Accepted Answer

A) spectrophotometry/turbidity 
B) spread-plating 
C) microscopy 
D) spread-plating,turbidity,and microscopy 
A) spectrophotometry/turbidity 
B) spread-plating 
C) microscopy 
D) spread-plating,turbidity,and microscopy

Question 19

Enumerating the viable and total cell concentration of a population of a microbial isolate can be a really laborious task for a microbiologist.Especially when a microbiologist studies the same isolate for several years,it often becomes practical to determine the relationship between optical density (OD)and cell concentration.Once this relationship (determined by a standard curve)is determined,the OD of an isolate in a broth can be routinely used to determine the population's concentration.Why must a standard curve be prepared for each isolate when using OD measurements to determine cell concentration? Also describe an experiment that would generate this type of standard curve.

Accepted Answer

Answers will vary,but it should be noted

Question 20

The time between inoculation and the beginning of growth is usually called the

Accepted Answer

A) lag phase. 
B) log phase. 
C) dormant phase. 
D) death phase. 
A) lag phase. 
B) log phase. 
C) dormant phase. 
D) death phase.

Exam 5: Microbial Growth and Control

The lag phase does NOT occur if all the cells in the culture are viable.

To determine the specific growth rate of a bacterial population,it is essential to know

A drug targeting ________ would NOT be an effective antibiotic.

Microbial growth is generally described as the increased number of cells rather than the expanding size of an individual microbial cell.

The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two.

A microbe growing in a refrigerator is likely

Counting chambers are used for estimating the number of cells present in a liquid culture.

In both lag and stationary phase,there is no net increase or decrease in viable cells.

Superoxide dismutase and catalase work together to convert superoxide into

Which is most abundant and active in divisome complexes?

Explain why a hyperthermophile is unlikely to be a human pathogen.

Enumerating cells in a biofilm is especially challenging for

One laboratory group repeated the same experiment described by others with the identical bacterial isolate and the same growth medium and conditions used but were unable to achieve the same O.D.at 600 nm.What is the LEAST likely cause for this discrepancy of turbidity measured?

Consider solution A (pH 6)and solution B (pH 9).Which of the following statements is CORRECT?

Organisms able to live in environments with high sugar concentrations are

An agar plate for counting colonies and maximizing statistical validity should ideally contain

Which of the following methods to enumerate cells often requires specialized staining to observe non-pigmented bacteria?

The time between inoculation and the beginning of growth is usually called the

Microorganisms and Microbiology

Microbial Cell Structure and Function

Microbial Metabolism

Molecular Biology

Microbial Genomics

Metabolic Regulation

Viruses and Virology

Viral Genomes and Diversity

Genetics of Bacteria and Archaea

Genetic Engineering and Biotechnology

Microbial Evolution and Systematics

Metabolic Diversity of Microorganisms

Functional Diversity of Bacteria

Diversity of Bacteria

Diversity of Archaea

Diversity of Eukaryotic Microorganisms

Methods in Microbial Ecology

Microbial Ecosystems

Nutrient Cycles

Microbiology of the Built Environment

Microbial Symbioses

Microbial Interactions With Humans

Immunity and Host Defense

Immune Mechanisms

Molecular Immunology

Diagnostic Microbiology

Epidemiology

Person-To-Person Bacterial and Viral Diseases

Vectorborne and Soilborne Bacterial and Viral Diseases

Water and Food As Vehicles of Bacterial Diseases

Eukaryotic Pathogens: Fungal and Parasitic Diseases

Filters