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Are you looking for some microbiology questions and answers to help you perfect your understanding before you sit for an exam? If you said yes, you are in luck as the quiz below is exactly what you need, how about you check it out and see how much work you need to put in, All the best and keep revising!
Questions and Answers
1.
When humans manipulate the genes of microorganisms the process is called
A.
Bioremediation
B.
Genetic engineering
C.
Epidermiology
D.
Immunology
E.
Taxonomy
Correct Answer
B. Genetic engineering
Explanation Genetic engineering refers to the process of manipulating the genes of microorganisms by humans. This involves altering the genetic material of the organisms to introduce new traits or modify existing ones. Bioremediation, on the other hand, refers to the use of microorganisms to clean up pollutants in the environment. Epidermiology is the study of skin diseases, immunology is the study of the immune system, and taxonomy is the classification of organisms. Therefore, the correct answer for the given question is genetic engineering.
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2.
The smallest and most significant taxon is
A.
Genus
B.
Species
C.
Kingdom
D.
Family
E.
Phylum
Correct Answer
B. Species
Explanation The smallest and most significant taxon is the species. In the biological classification system, species is the basic unit of classification. It refers to a group of organisms that share similar characteristics and can interbreed to produce fertile offspring. Species is more specific than genus, family, phylum, and kingdom, as it represents a unique group of organisms within a genus.
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3.
Which kingdom does not contain any eukaryotes?
A.
Monera
B.
Protista
C.
Mycetae
D.
Plantae
E.
Animalia
Correct Answer
A. Monera
Explanation Monera is the correct answer because it is the only kingdom that does not contain any eukaryotes. Monera consists of prokaryotic organisms, such as bacteria and blue-green algae, which lack a true nucleus and membrane-bound organelles. The other kingdoms, Protista, Mycetae, Plantae, and Animalia, all contain eukaryotic organisms, which have a true nucleus and membrane-bound organelles.
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4.
Which of the following is a scientific name?
A.
Bacteria
B.
Protista
C.
Species
D.
Bacillus subtilis
E.
Bacilli
Correct Answer
D. Bacillus subtilis
Explanation Bacillus subtilis is a scientific name because it follows the binomial nomenclature system used in biology. The name consists of two parts: the genus name, Bacillus, which refers to a specific group of bacteria, and the species name, subtilis, which specifies a particular type within that genus. This naming convention helps to provide a standardized and universal way of identifying and classifying organisms in the scientific community. In contrast, the other options given, such as bacteria, protista, species, and bacilli, are not specific scientific names but rather general terms or categories.
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5.
All of the following are correct about prokaryotes except
A.
They are smaller than eukaryotes
B.
They lack a nucleus
C.
They are less complex than eukaryotes
D.
They have organelles
E.
They are found nearly everywhere
Correct Answer
D. They have organelles
Explanation The given correct answer for this question is "they have organelles." Prokaryotes are single-celled organisms that lack a nucleus and membrane-bound organelles. They are generally smaller and less complex than eukaryotes. However, they are found nearly everywhere, including extreme environments such as hot springs, deep-sea vents, and even inside the human body.
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6.
When assigning a scientific name to an organism
A.
The species name is capitalized
B.
The species name is placed first
C.
The species name can be abbreviated
D.
Both genus and species name are capitalize
E.
Both genus and species name are italicized or underlined
Correct Answer
E. Both genus and species name are italicized or underlined
Explanation When assigning a scientific name to an organism, both the genus and species name are italicized or underlined. This is done to distinguish the scientific name from other types of names and to indicate that it is a Latinized binomial name consisting of two parts. The genus name is always capitalized, while the species name is not capitalized. It is important to use italics or underline to indicate that the scientific name is a formal taxonomic designation.
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7.
Which of the following is a taxon that contains all the other taxa listed?
A.
Species
B.
Phylum
C.
Kingdom
D.
Genus
E.
Family
Correct Answer
C. Kingdom
Explanation The correct answer is kingdom because it is the highest taxonomic rank and includes all other taxa such as species, phylum, genus, and family. Kingdom is a broad category that encompasses a wide range of organisms with similar characteristics. It is a hierarchical classification system used to organize and categorize living organisms based on their shared characteristics and evolutionary relationships.
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8.
All of the following pertain to photosynthesis except
A.
It occurs only in members of the kingdom Plantae
B.
Carbon dioxide is converted to organic material
C.
It contributes to the oxygen content in the atmosphere
D.
It is fueled by light
E.
It is important to each ecosystem's flow of energy and food
Correct Answer
A. It occurs only in members of the kingdom Plantae
Explanation Photosynthesis is a process that occurs in various organisms, not just members of the kingdom Plantae. It is a vital process that converts carbon dioxide into organic material and contributes to the oxygen content in the atmosphere. It is fueled by light and is crucial for the flow of energy and food in every ecosystem. Therefore, the statement "it occurs only in members of the kingdom Plantae" is incorrect.
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9.
Koch's postulates are criteria used to establish that
A.
Microbes are found on dust particles
B.
A specific microbe is the cause of a specific disease
C.
Life forms can only arise from preexisting life forms
D.
A specific microbe should be classified in a specific kingdom
E.
Microbes can be used to clean up toxic spills
Correct Answer
B. A specific microbe is the cause of a specific disease
Explanation Koch's postulates are a set of criteria used to determine whether a specific microbe is the cause of a specific disease. These postulates help establish a causal relationship between a microorganism and a disease by requiring that the microorganism be present in all cases of the disease, be isolated and grown in pure culture, cause the same disease when introduced into a healthy host, and be re-isolated from the newly infected host. By fulfilling these criteria, it can be concluded that the specific microbe is indeed the cause of the specific disease.
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10.
In Whittaker's system, the protozoa and algae are classified in the kingdom.
A.
Monera
B.
Protista
C.
Mycetae
D.
Plantae
E.
Animalia
Correct Answer
B. Protista
Explanation In Whittaker's system, the kingdom in which protozoa and algae are classified is Protista. This kingdom includes eukaryotic organisms that are unicellular or multicellular but lack specialized tissues. Protozoa are single-celled organisms that are classified in this kingdom due to their eukaryotic nature and ability to move independently. Algae, on the other hand, are photosynthetic organisms that can be unicellular or multicellular and are also classified in the kingdom Protista. Therefore, Protista is the correct answer for this question.
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11.
Helminths are
A.
Bacteria
B.
Protozoa
C.
Molds
D.
Parasitic worms
E.
Infectious particles
Correct Answer
D. Parasitic worms
Explanation Helminths are parasitic worms that infect and live in the bodies of humans and animals. They are a type of multicellular organism and can cause various diseases and infections. Unlike bacteria, protozoa, molds, and infectious particles, helminths are specifically classified as parasitic worms due to their characteristics and mode of infection. They have complex life cycles and can cause a wide range of health problems in their hosts.
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12.
Where are you most likely to find bacteria belonging to the domain Archaea?
A.
A human's large intestine
B.
In a hot spring
C.
A pond
D.
A sewage tratment plant
E.
A beer production facility
Correct Answer
B. In a hot spring
Explanation Bacteria belonging to the domain Archaea are most likely to be found in a hot spring. Hot springs are extreme environments with high temperatures, acidic or alkaline pH levels, and high concentrations of minerals. These conditions are similar to the habitats where Archaea thrive, as they are known to be extremophiles. They have adapted to survive in harsh environments such as hot springs, making it the most suitable location to find bacteria belonging to the domain Archaea.
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13.
Which of the following is the correct way to write the scientific name of this bacterium?
A.
Staph Aureus
B.
Staphylococcus Aureus
C.
Staphylococcus aureus
D.
Staphylococcus Aureus
E.
S. Aureus
Correct Answer
C. StapHylococcus aureus
Explanation The correct way to write the scientific name of this bacterium is "Staphylococcus aureus" because scientific names are written in italics and the genus name (Staphylococcus) is always capitalized while the species name (aureus) is always written in lowercase.
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14.
Spontaneous generation is the belief that
A.
Germs cause infectious diseases
B.
Microbes are diverse and ubiquitous
C.
Microbes placed in an infusion can grow in it
D.
Aseptic techniques reduce microbes in medical settings
E.
Living things arise from nonliving matter
Correct Answer
E. Living things arise from nonliving matter
Explanation The correct answer is "living things arise from nonliving matter." Spontaneous generation was a belief held in the past that living organisms could arise from nonliving matter. This theory was disproven by experiments conducted by Louis Pasteur, who showed that living organisms only come from preexisting life. This discovery led to the development of the concept of biogenesis, which states that living things can only be produced by other living things.
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15.
The microorganisms that recycle nutrients by breaking down dead matter and wastes are called
A.
Decomposers
B.
Procaryotes
C.
Pathogens
D.
Eucaryotes
E.
Fermenters
Correct Answer
A. Decomposers
Explanation Decomposers are microorganisms that play a crucial role in the ecosystem by breaking down dead matter and wastes. They help in the process of decomposition, which releases nutrients back into the environment, making them available for other organisms. Decomposers include bacteria, fungi, and certain types of protists. They break down organic matter into simpler forms, such as carbon dioxide, water, and minerals, which can then be used by plants and other organisms. This recycling of nutrients is essential for the balance and sustainability of the ecosystem.
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16.
Which of the following are the main decomposers of the earth?
A.
Bacteria and fungi
B.
Bacteria and viruses
C.
Algae and viruses
D.
Protists and fungi
E.
All organisms are decomposers
Correct Answer
A. Bacteria and fungi
Explanation Bacteria and fungi are the main decomposers of the earth because they play a crucial role in breaking down organic matter and recycling nutrients. Bacteria decompose dead plants and animals, while fungi break down complex organic compounds such as cellulose and lignin. Both bacteria and fungi secrete enzymes that break down these substances into simpler forms that can be absorbed by other organisms. This decomposition process is essential for nutrient cycling and the overall health of ecosystems.
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17.
A scientist discovers a new microbial species. It is a single-celled eucaryote without cell walls. In which
kingdom will it likely be classified?
A.
Monera
B.
Protista
C.
Fungi
D.
Animalia
E.
Plantae
Correct Answer
B. Protista
Explanation The scientist discovers a new microbial species that is a single-celled eucaryote without cell walls. Based on this information, it is likely to be classified in the kingdom Protista. This is because Protista is a kingdom that includes diverse eukaryotic organisms that do not fit into the other kingdoms such as Monera, Fungi, Animalia, or Plantae. Since the microbe is single-celled and lacks cell walls, it does not fit into the other kingdoms and is most likely to be classified as a Protista.
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18.
Disease-causing microorganisms are called
A.
Decomposers
B.
Procaryotes
C.
Pathogens
D.
Eucaryotes
E.
Fermenters
Correct Answer
C. Pathogens
Explanation Pathogens are disease-causing microorganisms. They can be bacteria, viruses, fungi, or parasites that invade the body and cause illness. These microorganisms have the ability to multiply and spread within the body, leading to various diseases and infections. Pathogens can be transmitted through direct contact, contaminated food or water, or through the air. They are a major concern in public health as they can cause epidemics and pandemics if not properly controlled and treated.
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19.
The microorganisms that do not have a nucleus in their cells are called
A.
Decomposers
B.
Procaryotes
C.
Pathogens
D.
Eucaryotes
E.
Fermenters
Correct Answer
B. Procaryotes
Explanation Prokaryotes are microorganisms that do not have a nucleus in their cells. They are single-celled organisms that lack membrane-bound organelles, including a nucleus. Prokaryotes include bacteria and archaea. They are known for their ability to adapt to various environments and play important roles in ecological processes such as decomposition.
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20.
Taxonomy does not involve
A.
Nomenclature
B.
Classification
C.
Taxa
D.
Identification
E.
Koch's postulates
Correct Answer
E. Koch's postulates
Explanation Taxonomy is the science of classifying and naming organisms based on their characteristics and evolutionary relationships. It involves the processes of nomenclature, classification, and identification. Nomenclature refers to the system of assigning scientific names to organisms, while classification involves grouping organisms into categories based on their similarities and differences. Identification is the process of determining the identity of an organism. However, Koch's postulates are not related to taxonomy. They are a set of criteria used to establish a causal relationship between a microorganism and a specific disease.
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21.
Select the correct descending taxonomic hierarchy (left to right)
A.
Family, order, class
B.
Family, genus, species
C.
Genus, species, family
D.
Class, phylum, order
E.
Kingdom, domain, phylum
Correct Answer
B. Family, genus, species
Explanation The correct descending taxonomic hierarchy is family, genus, species. In the Linnaean system of classification, organisms are grouped into increasingly specific categories. The family is a higher taxonomic rank that includes related genera. The genus is a more specific category that includes related species. The species is the most specific category and refers to a group of organisms that can interbreed and produce fertile offspring. Therefore, the correct order of the taxonomic hierarchy is family, genus, species.
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22.
Which activity is an example of biotechnology?
A.
Bacteria in the soil secreting an antibiotic to kill competitors
B.
A microbiologist using the microscope to study bacteria
C.
Humans using yeast to make beer and wine
D.
Mycobacteria tuberculosis in the lungs causing tuberculosis
E.
Public health officials monitoring diseases in a community
Correct Answer
C. Humans using yeast to make beer and wine
Explanation Humans using yeast to make beer and wine is an example of biotechnology because it involves the use of living organisms (yeast) to produce desired products (beer and wine). Biotechnology refers to the application of biological processes, organisms, or systems to develop or manufacture products or improve existing ones. In this case, yeast is used to ferment sugars in order to produce alcohol, which is a desired product.
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23.
Organisms called parasites are
A.
Always classified in the kingdom Monera
B.
Always harmful to their host
C.
The decomposers in ecosystems
D.
Always a virus
E.
Free-living
Correct Answer
B. Always harmful to their host
Explanation Parasites are organisms that live on or inside another organism (the host) and obtain nutrients at the expense of the host. They rely on the host for survival and reproduction, often causing harm or disease to the host in the process. This symbiotic relationship is characterized by the parasite benefiting while the host is negatively affected. Therefore, parasites are always harmful to their host.
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24.
Which of the following is not considered a microorganism?
A.
Mosquito
B.
Protozoa
C.
Bacteria
D.
Viruses
E.
Fungi
Correct Answer
A. Mosquito
Explanation A microorganism is a microscopic organism that can only be seen under a microscope. Mosquitoes are not considered microorganisms because they can be seen with the naked eye. On the other hand, protozoa, bacteria, viruses, and fungi are all examples of microorganisms as they are too small to be seen without the aid of a microscope.
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25.
A microbiologist inoculates Staphylococcus epidermidis and Escherichia coli into a culture medium.
Following incubation, only the E. coli grows in the culture. What is the most likely explanation?
A.
The microbiologist used too much inoculum
B.
The culture is contaminated
C.
The incubation temperature was incorrect
D.
The culture medium must be selective
E.
The culture medium must be differential
Correct Answer
D. The culture medium must be selective
Explanation The most likely explanation is that the culture medium used is selective. Selective culture media contain specific components that inhibit the growth of certain microorganisms while allowing the growth of others. In this case, the culture medium is likely designed to selectively promote the growth of Escherichia coli while inhibiting the growth of Staphylococcus epidermidis. This is why only the E. coli grows in the culture, indicating that the culture medium is selective.
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26.
Which of the following magnifies the specimen to produce the real image of the specimen?
A.
Condenser
B.
Objective lens
C.
Ocular lens
D.
Body
E.
Nosepiece
Correct Answer
B. Objective lens
Explanation The objective lens is responsible for magnifying the specimen to produce a real image. This lens is located close to the specimen and has a high magnification power. It collects and focuses the light that passes through the specimen, creating a magnified image that is projected into the microscope's eyepiece or ocular lens. The objective lens is crucial in determining the overall magnification of the microscope and plays a key role in producing a clear and detailed image of the specimen.
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27.
A microbiologist makes a fixed smear of bacterial cells and stains them with Loeffler's methylene blue. All the
cells appear blue under the oil lens. This is an example of
A.
Negative staining
B.
Using an acidic dye
C.
Simple staining
D.
Using the acid-fast stain
E.
Capsule staining
Correct Answer
C. Simple staining
Explanation The given scenario describes a microbiologist making a fixed smear of bacterial cells and staining them with Loeffler's methylene blue. In simple staining, a single dye is used to color all the cells in a sample, allowing for easy visualization under a microscope. In this case, the methylene blue dye is used, resulting in all the cells appearing blue. Therefore, the correct answer is simple staining.
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28.
A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible, would be termed
A.
Complex
B.
Reducing
C.
Enriched
D.
Enumeration
E.
Synthetic
Correct Answer
E. Synthetic
Explanation A nutrient medium that has all of its chemical components identified and their precise concentrations known and reproducible would be termed synthetic. This means that the medium is artificially created, with each component carefully measured and added in a controlled manner. This allows for precise control over the nutrients provided to the organisms growing in the medium, making it ideal for experimental purposes where consistency and reproducibility are important.
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29.
A microbiologist inoculates Staphylococcus aureus into a culture medium. Following incubation, both Staphylococcus aureus and Staphylococcus epidermidis are determined to be growing in this culture. What is the most likely explanation?
A.
The microbiologist used too much inoculum
B.
The culture is contaminated
C.
The incubation temperature was incorrect
D.
The culture medium must be selective
E.
The culture medium must be differential
Correct Answer
B. The culture is contaminated
Explanation The presence of both Staphylococcus aureus and Staphylococcus epidermidis in the culture suggests that the culture has been contaminated. Contamination can occur due to various reasons such as improper sterilization techniques, introduction of outside microorganisms during inoculation, or inadequate handling of the culture. This contamination can lead to the growth of unintended microorganisms in the culture medium.
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30.
If a microbiologist is studying a specimen at a total magnification of 950X, what is the magnifying power of the objective lens if the ocular lens is 10X?
A.
100X
B.
950X
C.
85X
D.
850X
E.
95X
Correct Answer
E. 95X
Explanation The total magnification of a microscope is calculated by multiplying the magnification of the objective lens by the magnification of the ocular lens. In this case, the ocular lens has a magnification of 10X. Therefore, if the total magnification is 950X, the magnifying power of the objective lens can be determined by dividing the total magnification by the magnification of the ocular lens: 950X / 10X = 95X.
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31.
All of the following are correct about agar except
A.
It is flexible
B.
It melts at the boiling point of water (100^C)
C.
It is a source of nutrition for bacteria
D.
It solidifies below 42^C
E.
It is solid at room temperature
Correct Answer
A. It is flexible
Explanation Agar is a substance derived from seaweed that is commonly used in laboratories as a solidifying agent for culture media. It is not flexible, as it solidifies into a gel-like substance when cooled. Therefore, the statement "It is flexible" is incorrect.
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32.
Which type of medium is able to distinguish different species or types of microorganisms based on an observable change in the colonies or in the medium?
A.
Differential
B.
Selective
C.
Enumeration
D.
Enriched
E.
Reducing
Correct Answer
A. Differential
Explanation Differential medium is able to distinguish different species or types of microorganisms based on an observable change in the colonies or in the medium. This means that it contains specific ingredients or indicators that allow for the differentiation of microorganisms based on their ability to metabolize certain substances or produce characteristic growth patterns. Selective medium, on the other hand, is designed to inhibit the growth of certain microorganisms while allowing others to grow. Enumeration medium is used to determine the number of viable microorganisms in a sample. Enriched medium contains additional nutrients to support the growth of fastidious microorganisms. Reducing medium creates an environment with low oxygen levels to support the growth of anaerobic microorganisms.
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33.
A common medium used for growing fastidious bacteria is
A.
Blood agar
B.
Trypticase soy agar
C.
Mannitol salt agar
D.
MacConkey medium
E.
A reducing medium
Correct Answer
A. Blood agar
Explanation Blood agar is a common medium used for growing fastidious bacteria because it provides essential nutrients and growth factors that these bacteria require for their growth. It contains a mixture of agar and blood, usually sheep or horse blood, which provides a rich source of nutrients such as amino acids, vitamins, and minerals. The blood also serves as an indicator of hemolysis, which can help in identifying certain bacteria species. Overall, blood agar is an ideal medium for cultivating fastidious bacteria due to its nutrient-rich composition and ability to support their growth requirements.
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34.
Bacteria that require special growth factors and complex organic substances are called
A.
Fastidious
B.
Pathogenic
C.
Harmless
D.
Anaerobic
E.
Aerobic
Correct Answer
A. Fastidious
Explanation Fastidious bacteria are those that require specific growth factors and complex organic substances in order to survive and reproduce. These bacteria have specific nutritional requirements that must be met in order for them to grow and thrive. They are often more difficult to culture in the laboratory compared to other bacteria that have less specific nutritional needs. Therefore, the correct answer is fastidious.
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35.
The term that refers to the purposeful addition of microorganisms into a laboratory nutrient medium is
A.
Isolation
B.
Inoculation
C.
Immunization
D.
Infection
E.
Contamination
Correct Answer
B. Inoculation
Explanation Inoculation refers to the deliberate introduction of microorganisms into a laboratory nutrient medium. This is done for the purpose of studying and growing these microorganisms in a controlled environment. It involves transferring a small amount of the desired microorganism onto the medium, allowing it to multiply and form colonies. Inoculation is an essential step in microbiology research and allows scientists to study and identify different microorganisms and their characteristics.
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36.
The primary purpose of staining cells on a microscope slide is to
A.
Kill them
B.
Secure them to the slide
C.
Enlarge the cells
D.
Add contrast in order to see them better
E.
See motility
Correct Answer
D. Add contrast in order to see them better
Explanation Staining cells on a microscope slide is done to add contrast, allowing for better visualization of the cells. By using stains, the cells become more distinguishable from their surroundings, making it easier to observe their structure, shape, and other characteristics under the microscope. Staining does not kill the cells, secure them to the slide, enlarge them, or help in observing their motility.
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37.
All of the following are examples of different types of microbiological media except
A.
Broth
B.
Enriched
C.
Agar
D.
Petri dish
E.
Gelatin
Correct Answer
D. Petri dish
Explanation A petri dish is not an example of a type of microbiological media. It is a shallow, flat, cylindrical dish made of glass or plastic that is used to hold agar or other types of media for culturing microorganisms. It is not a specific type of media itself, but rather a container used to hold the media.
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38.
A media is designed that allows only Staphylococci to grow. In addition, S. aureus colonies have a yellow halo around them and other staphylococci appear white. This type of media is
A.
Selective only
B.
Differential only
C.
Both selective and differential
D.
A reducing media
E.
Enriched
Correct Answer
C. Both selective and differential
Explanation This type of media is both selective and differential. It is selective because it only allows Staphylococci to grow, inhibiting the growth of other bacteria. It is differential because it allows for the differentiation of different types of Staphylococci. S. aureus colonies have a yellow halo around them, which distinguishes them from other staphylococci that appear white. Therefore, this media serves the purpose of selecting for Staphylococci while also allowing for the differentiation of different Staphylococcus species based on their colony appearance.
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39.
Which of the following will result when 1% to 5% agar is added to nutrient broth, boiled and cooled?
A.
A pure culture
B.
A mixed culture
C.
A solid medium
D.
A liquid medium
E.
A contaminated medium
Correct Answer
C. A solid medium
Explanation When 1% to 5% agar is added to nutrient broth, boiled, and cooled, it solidifies to form a gel-like substance. This solid medium provides a surface for the growth of microorganisms. Therefore, the correct answer is a solid medium.
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40.
The Gram stain, acid-fast stain and endospore stain have the following in common:
A.
Used on a wet mount of the specimen
B.
Use heat to force the dye into cell structures
C.
Outcome based on cell wall differences
D.
Use a negative stain technique
E.
Are differential stains
Correct Answer
E. Are differential stains
Explanation The Gram stain, acid-fast stain, and endospore stain are all examples of differential stains. Differential stains are used to distinguish between different types of bacteria or cell structures based on specific characteristics. In this case, all three stains are used to differentiate between different types of cells based on their cell wall differences. These stains also require the use of heat to force the dye into the cell structures and are typically used on wet mounts of the specimen. However, they do not use a negative stain technique, which involves staining the background rather than the cells.
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41.
All of the following pertain to the fluorescence microscope except it
A.
Uses electron's to produce a specimen image
B.
Type of compound microscope
C.
Requires the use of dyes like acridine and fluorescein
D.
Commonly used to diagnose certain infections
E.
Requires an ultraviolet radiation source
Correct Answer
A. Uses electron's to produce a specimen image
Explanation The fluorescence microscope does not use electrons to produce a specimen image. Instead, it relies on the principle of fluorescence, where certain substances emit light when exposed to specific wavelengths of light. This microscope uses a high-intensity light source, typically ultraviolet radiation, to excite fluorescent dyes or molecules in the specimen. The emitted light is then captured and magnified by the microscope's lenses, allowing for the visualization of specific structures or molecules within the specimen. This technique is commonly used in various fields, including biology, medicine, and materials science.
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42.
A pure culture contains only
A.
One species of microorganism
B.
Bacteria
C.
A variety of microbes from one source
D.
A variety of species from the same genus
E.
None of the choices are correct
Correct Answer
A. One species of microorganism
Explanation A pure culture contains only one species of microorganism, meaning that it consists of a population of microorganisms that are all genetically identical and belong to the same species. This is achieved by isolating and growing a single microorganism in a laboratory setting, ensuring that there are no other types of microorganisms present. By having a pure culture, scientists can study the specific characteristics and behavior of a particular microorganism without any interference from other species or strains.
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43.
The five I's of studying microorganisms include all of the following except
A.
Inoculation
B.
Incubation
C.
Infection
D.
Isolation
E.
Identification
Correct Answer
C. Infection
Explanation The five I's of studying microorganisms include inoculation, incubation, isolation, and identification. Infection is not one of the five I's because it refers to the invasion and multiplication of pathogens in a host organism, rather than a step in the process of studying microorganisms. The other four I's involve specific techniques used in the laboratory to study and manipulate microorganisms for research purposes.
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44.
Which of the following puts the Five "I"s in their correct order?
Correct Answer
A. Inoculation, incubation, isolation, inspection, identification
Explanation The correct order of the Five "I"s is as follows: inoculation, incubation, isolation, inspection, identification. This sequence is logical in the context of a process such as laboratory testing or disease control. Inoculation refers to introducing a substance (such as a vaccine or a sample) into a system. Incubation is the period of time during which the substance is allowed to develop or grow. Isolation involves separating the substance or subject from its surroundings. Inspection is the act of closely examining the substance or subject. Identification is the final step in determining the nature or characteristics of the substance or subject.
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45.
This microscope does not use light in forming the specimen image:
A.
Bright-field
B.
Dark-field
C.
Phase-contrast
D.
Fluorescence
E.
Electron
Correct Answer
E. Electron
Explanation Electron microscopes use a beam of electrons instead of light to form the specimen image. This is achieved by passing the electron beam through the specimen, which interacts with the electrons in the specimen to produce an image. Unlike light microscopes, electron microscopes have much higher resolution and can visualize smaller structures due to the shorter wavelength of electrons compared to light. Therefore, electron microscopes do not rely on light in forming the specimen image.
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46.
The type of microscope in which you would see brightly illuminated specimens against a black background is
A.
Bright-field
B.
Dark-field
C.
Phase-contrast
D.
Fluorescence
E.
Electron
Correct Answer
B. Dark-field
Explanation Dark-field microscopy is a type of microscope that uses a special lighting technique to observe specimens against a black background. This technique involves illuminating the specimen from the side, causing the light to scatter off the specimen and create a bright image against a dark background. This method is particularly useful for observing transparent or unstained specimens, as it enhances contrast and reveals details that may be difficult to see with other types of microscopy.
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