Chamberlain University
1 KEEW • 242 SOIB
★ ★
C College of Nursing & Health Professions
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Week 1 Review
B R A N C H E S O F M I C R O B I O LO G Y · H I STO R Y · M I C R O S CO P Y · STA I N I N G · G E N E T I CS & M U TAT I O N S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
WEEK Week 1 — Foundations of Microbiology TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
WEEK 1 REVIEW INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This review covers branches of microbiology, historical figures, microscopy, staining techniques, and microbial genetics.
▸ All content reflects BIOS 242 Week 1 learning objectives.
▸ Correct answers and detailed rationales appear below each question for exam preparation purposes.
▸ Pay careful attention to microscope types, Gram stain steps, and mutation classifications.
SECTION I — BRANCHES, HISTORY, MICROSCOPY, STAINING & GENETICS Questions 1 – 25
1. The six branches of microbiology each have distinct focuses. Which branch ensures the safety of food and water supplies and uses biotechnology to produce
bread, biofuels, and gene therapy products?
A. Medical Microbiology
B. Public Health Microbiology and Epidemiology
C. Industrial Microbiology
D. Agricultural Microbiology
CORRECT ANSWER C — Industrial Microbiology
RATIONALE Industrial microbiology safeguards food and water and uses biotechnology to harness microbial metabolism for producing bread, biofuels, gene therapy, and
other products. Medical microbiology focuses on microorganisms causing illnesses in humans and animals. Public health microbiology and epidemiology
oversees and manages disease dissemination within societies. Immunology delves into defensive elements and cells generated in reaction to infection.
Agricultural microbiology involves interactions between microorganisms and cultivated plants/domesticated animals. Environmental microbiology investigates
microorganisms in the varied ecosystems of our planet.
2. Louis Pasteur made which foundational contributions to microbiology?
A. Created simple microscopes and observed 'animalcules' in dental plaque and pond water
B. Developed four postulates to prove a microbe causes a specific disease
C. Used swan neck flasks to disprove spontaneous generation and demonstrated that microorganisms are responsible for disease
D. Developed the binomial system of nomenclature for naming organisms
CORRECT ANSWER C — Used swan neck flasks to disprove spontaneous generation; demonstrated microorganisms cause disease
RATIONALE Louis Pasteur disproved spontaneous generation using swan neck flasks — sterile broth remained sterile unless the flask neck was broken, allowing airborne
microbes to enter. He also developed pasteurization, the germ theory of disease, and the first rabies vaccine. Option A describes Antonie van Leeuwenhoek (built
300x microscopes, observed "animalcules"). Option B describes Robert Koch (Koch's postulates linking specific microbes to specific diseases). Option D describes
Carl von Linné (developed binomial nomenclature — genus capitalized first, species lowercase second, both italicized).
3. Robert Koch developed four postulates that must be met to prove a microbe causes a specific disease. Which of the following correctly represents the first
postulate?
A. The pathogen must be isolated from the diseased host and grown in pure culture
B. The same pathogen must be present in every case of the disease
C. The pathogen from pure culture must cause the disease when inoculated into a healthy host
D. The pathogen must be re-isolated from the experimentally infected host
CORRECT ANSWER B — The same pathogen must be present in every case of the disease
RATIONALE Koch's four postulates: (1) The same pathogen must be present in every case of the disease; (2) The pathogen must be isolated from the diseased host and grown
in pure culture; (3) The pathogen from pure culture must cause the disease when inoculated into a healthy, susceptible host; (4) The pathogen must be re-isolated
from the experimentally infected host and shown to be the original organism. These postulates established the germ theory of disease and remain a cornerstone
of medical microbiology. Koch also discovered the causative agent for anthrax (Bacillus anthracis).
, 4. The binomial system of nomenclature requires that scientific names be written in which format?
A. Species name first (capitalized), genus name second (lowercase), both underlined
B. Genus name first (capitalized), species name second (lowercase), both typed in italics
C. Both names in all capital letters, separated by a hyphen
D. Only the genus name is used; the species is indicated by a number
CORRECT ANSWER B — Genus first (capitalized), species second (lowercase), both in italics
RATIONALE The binomial system of nomenclature, developed by Carl von Linné, requires: genus name written first with the first letter capitalized, species name written
second and beginning with a lowercase letter, and both names typed in italics (or underlined when handwritten). Example: Escherichia coli or Staphylococcus
aureus. This standardized naming system provides a universal language for scientific communication across all biological disciplines. The genus groups similar
organisms; the species identifies the specific organism within that genus.
5. A bright field light microscope forms an image by:
A. Using a laser beam to scan various depths and deliver a sharp image on a single plane
B. Transmitting light through the specimen — the specimen absorbs some light, producing a darker image against a brightly illuminated field
C. Blocking all light except peripheral light reflected off the specimen's sides, producing a bright specimen on a dark background
D. Bombarding the surface of a metal-coated specimen with electrons
CORRECT ANSWER B — Light transmitted through specimen; specimen absorbs some light → darker image against bright field
RATIONALE A bright field light microscope forms an image when light is transmitted through the specimen. The specimen absorbs some light, and the rest is transmitted to
the objective lens. The specimen appears darker than the surrounding brightly illuminated field. Other types: Dark field — uses a "stop" disc blocking all light
except peripheral light, producing a bright specimen on a dark background. Phase contrast — transforms changes in light waves into differences in light intensity
for viewing live unstained specimens. Differential interference contrast — uses two prisms and two light beams adding contrasting colors. Fluorescence — uses UV
radiation and fluorescent dyes. Confocal — uses laser beam scanning for single-plane sharp images. TEM — transmits electrons through specimen. SEM —
bombards metal-coated surface with electrons.
6. A phase contrast microscope is particularly useful for:
A. Viewing metal-coated specimens at very high magnification
B. Providing detailed views of unstained, live specimens by transforming changes in light waves into differences in light intensity
C. Producing three-dimensional surface images
D. Viewing specimens stained with fluorescent dyes under UV light
CORRECT ANSWER B — Views unstained live specimens by transforming light wave changes into light intensity differences
RATIONALE The phase contrast microscope transforms changes in light waves passing through the specimen into differences in light intensity. Denser cell regions alter the
light pathway more than less dense regions, creating contrast without staining. This allows observation of live, unstained specimens in their natural state. The
differential interference contrast (DIC) microscope adds two prisms for contrasting colors and uses two beams of light. Simple fluorescence requires fluorescent
dye staining and UV radiation. Confocal fluorescence uses a laser scanning various depths. TEM and SEM use electrons rather than light.
7. Which staining technique uses India ink to identify bacterial capsules by staining the slide background but not the capsule itself?
A. Simple stain
B. Positive stain
C. Negative stain
D. Differential stain
CORRECT ANSWER C — Negative stain
RATIONALE A negative stain uses India ink (or nigrosin) to stain the background of the slide but NOT the bacterial capsule. The capsule appears as a clear halo around the
bacterial cell against a dark background — this is the standard method for visualizing capsules. A positive stain adheres to the specimen but not the slide. A simple
stain uses a single stain to determine shape, size, and arrangement. A differential stain uses two different stains (primary and counterstain) to differentiate
between cell types — the Gram stain is the most important example. Special stains detect specific structures like flagella and capsules.
8. The central dogma of molecular biology describes the flow of genetic information. The correct sequence is:
A. Protein → RNA → DNA
B. DNA replication → DNA transcription (to mRNA) → mRNA translation (to protein)
C. DNA → Protein → RNA
D. RNA → DNA → Protein
CORRECT ANSWER B — DNA replication → DNA transcription (to mRNA) → mRNA translation (to protein)
RATIONALE The central dogma: DNA replication duplicates the genetic material. DNA transcription copies DNA into messenger RNA (mRNA). mRNA translation uses the
information in mRNA to synthesize proteins. This unidirectional flow of genetic information is universal in all living organisms. Horizontal gene transfer is the
process where DNA from one microorganism is transferred to a different microorganism through three mechanisms: transformation (recipient cell alive, donor
dead — free DNA uptake), conjugation (pilus-mediated direct transfer), and transduction (bacteriophage-mediated transfer). Transposons are "jumping genes"
that shift within the genome.
1 KEEW • 242 SOIB
★ ★
C College of Nursing & Health Professions
J O U R N E Y T O E X T R A O R D I N A R Y CO M PA S S I O N AT E C A R E
EST. 1889
BIOS 242 — Week 1 Review
B R A N C H E S O F M I C R O B I O LO G Y · H I STO R Y · M I C R O S CO P Y · STA I N I N G · G E N E T I CS & M U TAT I O N S
INSTITUTION Chamberlain University COURSE CODE BIOS 242
PROGRAM Bachelor of Science in Nursing (BSN) ACADEMIC YEAR
WEEK Week 1 — Foundations of Microbiology TOTAL QUESTIONS 25 Questions
COURSE TITLE Fundamentals of Microbiology FORMAT Multiple Choice — Select the Single Best Answer
WEEK 1 REVIEW INSTRUCTIONS
▸ Select the single best answer for each question unless otherwise instructed.
▸ This review covers branches of microbiology, historical figures, microscopy, staining techniques, and microbial genetics.
▸ All content reflects BIOS 242 Week 1 learning objectives.
▸ Correct answers and detailed rationales appear below each question for exam preparation purposes.
▸ Pay careful attention to microscope types, Gram stain steps, and mutation classifications.
SECTION I — BRANCHES, HISTORY, MICROSCOPY, STAINING & GENETICS Questions 1 – 25
1. The six branches of microbiology each have distinct focuses. Which branch ensures the safety of food and water supplies and uses biotechnology to produce
bread, biofuels, and gene therapy products?
A. Medical Microbiology
B. Public Health Microbiology and Epidemiology
C. Industrial Microbiology
D. Agricultural Microbiology
CORRECT ANSWER C — Industrial Microbiology
RATIONALE Industrial microbiology safeguards food and water and uses biotechnology to harness microbial metabolism for producing bread, biofuels, gene therapy, and
other products. Medical microbiology focuses on microorganisms causing illnesses in humans and animals. Public health microbiology and epidemiology
oversees and manages disease dissemination within societies. Immunology delves into defensive elements and cells generated in reaction to infection.
Agricultural microbiology involves interactions between microorganisms and cultivated plants/domesticated animals. Environmental microbiology investigates
microorganisms in the varied ecosystems of our planet.
2. Louis Pasteur made which foundational contributions to microbiology?
A. Created simple microscopes and observed 'animalcules' in dental plaque and pond water
B. Developed four postulates to prove a microbe causes a specific disease
C. Used swan neck flasks to disprove spontaneous generation and demonstrated that microorganisms are responsible for disease
D. Developed the binomial system of nomenclature for naming organisms
CORRECT ANSWER C — Used swan neck flasks to disprove spontaneous generation; demonstrated microorganisms cause disease
RATIONALE Louis Pasteur disproved spontaneous generation using swan neck flasks — sterile broth remained sterile unless the flask neck was broken, allowing airborne
microbes to enter. He also developed pasteurization, the germ theory of disease, and the first rabies vaccine. Option A describes Antonie van Leeuwenhoek (built
300x microscopes, observed "animalcules"). Option B describes Robert Koch (Koch's postulates linking specific microbes to specific diseases). Option D describes
Carl von Linné (developed binomial nomenclature — genus capitalized first, species lowercase second, both italicized).
3. Robert Koch developed four postulates that must be met to prove a microbe causes a specific disease. Which of the following correctly represents the first
postulate?
A. The pathogen must be isolated from the diseased host and grown in pure culture
B. The same pathogen must be present in every case of the disease
C. The pathogen from pure culture must cause the disease when inoculated into a healthy host
D. The pathogen must be re-isolated from the experimentally infected host
CORRECT ANSWER B — The same pathogen must be present in every case of the disease
RATIONALE Koch's four postulates: (1) The same pathogen must be present in every case of the disease; (2) The pathogen must be isolated from the diseased host and grown
in pure culture; (3) The pathogen from pure culture must cause the disease when inoculated into a healthy, susceptible host; (4) The pathogen must be re-isolated
from the experimentally infected host and shown to be the original organism. These postulates established the germ theory of disease and remain a cornerstone
of medical microbiology. Koch also discovered the causative agent for anthrax (Bacillus anthracis).
, 4. The binomial system of nomenclature requires that scientific names be written in which format?
A. Species name first (capitalized), genus name second (lowercase), both underlined
B. Genus name first (capitalized), species name second (lowercase), both typed in italics
C. Both names in all capital letters, separated by a hyphen
D. Only the genus name is used; the species is indicated by a number
CORRECT ANSWER B — Genus first (capitalized), species second (lowercase), both in italics
RATIONALE The binomial system of nomenclature, developed by Carl von Linné, requires: genus name written first with the first letter capitalized, species name written
second and beginning with a lowercase letter, and both names typed in italics (or underlined when handwritten). Example: Escherichia coli or Staphylococcus
aureus. This standardized naming system provides a universal language for scientific communication across all biological disciplines. The genus groups similar
organisms; the species identifies the specific organism within that genus.
5. A bright field light microscope forms an image by:
A. Using a laser beam to scan various depths and deliver a sharp image on a single plane
B. Transmitting light through the specimen — the specimen absorbs some light, producing a darker image against a brightly illuminated field
C. Blocking all light except peripheral light reflected off the specimen's sides, producing a bright specimen on a dark background
D. Bombarding the surface of a metal-coated specimen with electrons
CORRECT ANSWER B — Light transmitted through specimen; specimen absorbs some light → darker image against bright field
RATIONALE A bright field light microscope forms an image when light is transmitted through the specimen. The specimen absorbs some light, and the rest is transmitted to
the objective lens. The specimen appears darker than the surrounding brightly illuminated field. Other types: Dark field — uses a "stop" disc blocking all light
except peripheral light, producing a bright specimen on a dark background. Phase contrast — transforms changes in light waves into differences in light intensity
for viewing live unstained specimens. Differential interference contrast — uses two prisms and two light beams adding contrasting colors. Fluorescence — uses UV
radiation and fluorescent dyes. Confocal — uses laser beam scanning for single-plane sharp images. TEM — transmits electrons through specimen. SEM —
bombards metal-coated surface with electrons.
6. A phase contrast microscope is particularly useful for:
A. Viewing metal-coated specimens at very high magnification
B. Providing detailed views of unstained, live specimens by transforming changes in light waves into differences in light intensity
C. Producing three-dimensional surface images
D. Viewing specimens stained with fluorescent dyes under UV light
CORRECT ANSWER B — Views unstained live specimens by transforming light wave changes into light intensity differences
RATIONALE The phase contrast microscope transforms changes in light waves passing through the specimen into differences in light intensity. Denser cell regions alter the
light pathway more than less dense regions, creating contrast without staining. This allows observation of live, unstained specimens in their natural state. The
differential interference contrast (DIC) microscope adds two prisms for contrasting colors and uses two beams of light. Simple fluorescence requires fluorescent
dye staining and UV radiation. Confocal fluorescence uses a laser scanning various depths. TEM and SEM use electrons rather than light.
7. Which staining technique uses India ink to identify bacterial capsules by staining the slide background but not the capsule itself?
A. Simple stain
B. Positive stain
C. Negative stain
D. Differential stain
CORRECT ANSWER C — Negative stain
RATIONALE A negative stain uses India ink (or nigrosin) to stain the background of the slide but NOT the bacterial capsule. The capsule appears as a clear halo around the
bacterial cell against a dark background — this is the standard method for visualizing capsules. A positive stain adheres to the specimen but not the slide. A simple
stain uses a single stain to determine shape, size, and arrangement. A differential stain uses two different stains (primary and counterstain) to differentiate
between cell types — the Gram stain is the most important example. Special stains detect specific structures like flagella and capsules.
8. The central dogma of molecular biology describes the flow of genetic information. The correct sequence is:
A. Protein → RNA → DNA
B. DNA replication → DNA transcription (to mRNA) → mRNA translation (to protein)
C. DNA → Protein → RNA
D. RNA → DNA → Protein
CORRECT ANSWER B — DNA replication → DNA transcription (to mRNA) → mRNA translation (to protein)
RATIONALE The central dogma: DNA replication duplicates the genetic material. DNA transcription copies DNA into messenger RNA (mRNA). mRNA translation uses the
information in mRNA to synthesize proteins. This unidirectional flow of genetic information is universal in all living organisms. Horizontal gene transfer is the
process where DNA from one microorganism is transferred to a different microorganism through three mechanisms: transformation (recipient cell alive, donor
dead — free DNA uptake), conjugation (pilus-mediated direct transfer), and transduction (bacteriophage-mediated transfer). Transposons are "jumping genes"
that shift within the genome.
