Test Your Microbiology Skills - Quiz
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Which of the following terms describes organisms that thrive in the cold?
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Mesophiles
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Thermophiles
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Psychrophiles
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Aerophiles
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Microbiology is the study of very tiny organisms, formally knows as microorganisms, especially those which cause infections and diseases. It is one of the most important branches of microbiology. Take this test and learn more about the study of microorganisms.
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- 2.
An organism is completely dependant on atmospheric O2 for growth. This organism is a(n)
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Osmotolerant
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Facultative anaerob
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Obligate aerob
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Acidophile
Correct Answer
A. Obligate aerobExplanation
An organism that is completely dependent on atmospheric O2 for growth is classified as an obligate aerobe. This means that it requires oxygen to carry out its metabolic processes and cannot survive in the absence of oxygen. Obligate aerobes have adapted to utilize oxygen as their terminal electron acceptor in respiration, which is essential for generating energy. Without oxygen, these organisms are unable to produce enough energy to sustain their growth and survival.Rate this question:
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- 3.
The term facultative anaerobe refers to an organism that _________
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Uses oxygen when present or grows without oxygen when oxygen is absent
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Doesn't use oxygen but tolerates it
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Prefers to grow without oxygen
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Is killed by oxygen.
Correct Answer
A. Uses oxygen when present or grows without oxygen when oxygen is absentExplanation
A facultative anaerobe is an organism that has the ability to survive and grow in both the presence and absence of oxygen. This means that when oxygen is available, it can use it for its metabolic processes, but it can also switch to alternative pathways to generate energy in the absence of oxygen. Therefore, a facultative anaerobe can adapt its metabolism based on the oxygen availability in its environment.Rate this question:
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- 4.
A microbiology student noticed that a culture broth tube was very turbid at the surface but clear throughout the rest of the tube. She can conclude that the ____________
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Organism should be grown in an anaerobic chamber.
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Organism cannot produce superoxide dismutase and/or catalase.
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Organism are aerobes.
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Broth is sterile.
Correct Answer
A. Organism are aerobes.Explanation
Based on the information provided, the student observed that the culture broth tube was turbid at the surface but clear throughout the rest of the tube. This suggests that the organism requires oxygen to grow, as it is concentrated at the surface where oxygen is available. Therefore, the correct conclusion is that the organism is an aerobe, which means it can only grow in the presence of oxygen.Rate this question:
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- 5.
Which of the following procedures can be used to isolate a pure culture of a bacterium from a mixture?
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Streak plating
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Dilution plating
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Enrichment culture
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All the above can be used to isolate a pure culture of a bacterium from a mixture.
Correct Answer
A. Streak platingExplanation
Streak plating is a procedure commonly used to isolate a pure culture of a bacterium from a mixture. In this method, a small amount of the bacterial mixture is streaked onto a solid agar plate using an inoculating loop. As the loop is dragged across the surface of the agar, the bacteria are spread out and diluted. This allows for individual bacterial cells to grow into separate colonies. By picking a single colony and transferring it to a new plate, a pure culture of the bacterium can be obtained. Dilution plating and enrichment culture are also valid methods for isolating pure cultures, but the question specifically asks for procedures that can be used, so the correct answer is that all of the above methods can be used.Rate this question:
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- 6.
Addition of blood to a culture medium only allows the hemolytic bacteria that grow on the plate to be picked out. This is an example of a
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Liquid media.
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Chemically defined media.
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Selective media.
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Differential media.
Correct Answer
A. Differential media.Explanation
The addition of blood to a culture medium allows for the differentiation of bacteria based on their ability to cause hemolysis, or the breakdown of red blood cells. This is because certain bacteria have the ability to produce enzymes that can lyse red blood cells, resulting in a clear zone around the bacterial colony on the plate. By using blood as a component of the culture medium, only the hemolytic bacteria can be distinguished and picked out, making it an example of differential media.Rate this question:
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- 7.
Addition of salt to a culture medium only allows the salt-tolerant bacteria to grow. This is an example of a
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Complex media.
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Selective media.
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Enriched media.
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Differential media.
Correct Answer
A. Selective media.Explanation
The addition of salt to a culture medium creates a selective environment where only salt-tolerant bacteria can thrive and grow. This is because the high salt concentration inhibits the growth of salt-sensitive bacteria, allowing only the salt-tolerant ones to survive. Selective media is used to selectively promote the growth of specific types of microorganisms while inhibiting the growth of others, making it the correct answer in this case.Rate this question:
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- 8.
Plates should be incubated
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Agar side up
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Agar side down
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It doesn't matter
Correct Answer
A. Agar side upExplanation
Plates should be incubated agar side up because this allows for proper air circulation and prevents condensation from accumulating on the agar surface. Incubating the plates agar side down could result in the growth of microorganisms on the lid, which can contaminate the agar surface and affect the results of the experiment. Therefore, incubating the plates agar side up is the correct and recommended method.Rate this question:
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- 9.
When streaking a plate, the lid should be
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placed on the bench top, top side up
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Placed on the bench top, inside surface up
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Should be held in the same hand as the plate
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Should be held in the opposite hand from the plate
Correct Answer
A. Placed on the bench top, inside surface upExplanation
When streaking a plate, it is important to place the lid on the bench top with the inside surface facing up. This is because the inside surface of the lid is sterile, while the outside surface may come into contact with potential contaminants on the bench top. Placing the lid with the inside surface up helps to maintain the sterility of the lid and minimize the risk of introducing contaminants to the plate.Rate this question:
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- 10.
When streaking a plate, the loop should be flamed
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At the beginning and end
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At the beginning and end and between the first 2 zones
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At the beginning and end and between each zone
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At the beginning and end and between the second and third zone
Correct Answer
A. At the beginning and end and between each zoneExplanation
When streaking a plate, the loop should be flamed at the beginning and end and between each zone. Flaming the loop ensures that any microorganisms present on the loop are killed, preventing contamination of the next zone or the original culture. Flaming also helps to sterilize the loop before and after use, reducing the risk of cross-contamination between different samples. By flaming at the beginning and end and between each zone, the loop is effectively sterilized throughout the streaking process, maintaining the integrity of the culture and preventing unwanted contamination.Rate this question:
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- 11.
Which of these factors will not affect your Gram stain results? (Given that everything else is done correctly.)
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Bacterial Age
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Reagent Quality
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Excessive Washing of Slide
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Sample Thickness
Correct Answer
A. Excessive Washing of SlideExplanation
Excessive washing should only be a problem if you had not heat fixed your slide; in which case you would have problems anyway.
Besides the three options listed earlier (Sample thickness, bacterial age and reagent quality), excessive rinsing with alcohol and overheating the bacteria will also affect your Gram result.Rate this question:
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- 12.
During log phase, bacteria are
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Preparing to divide.
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Dying and dividing in equal numbers.
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Dying exponentially.
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Dividing at the fastest possible rate.
Correct Answer
A. Dividing at the fastest possible rate.Explanation
During the log phase, bacteria are dividing at the fastest possible rate. This phase is characterized by a rapid increase in the number of bacterial cells as they undergo binary fission, where one cell divides into two identical daughter cells. The conditions during this phase are optimal for growth, with abundant nutrients and favorable environmental factors. As a result, the bacteria are able to divide quickly and efficiently, leading to exponential growth and an increase in population size.Rate this question:
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- 13.
What stain technique has been use for this staining?
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Gram staining
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Endospore Staining
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Acid fast staining
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Simple staining
Correct Answer
A. Endospore StainingExplanation
Endospore staining is the correct answer because it is a specific staining technique used to visualize endospores, which are dormant forms of bacteria. This technique involves the use of heat and specific dyes to differentiate between endospores and other cellular structures. Gram staining is used to classify bacteria into Gram-positive and Gram-negative based on cell wall characteristics. Acid-fast staining is used to identify acid-fast bacteria, such as Mycobacterium tuberculosis. Simple staining is a basic staining technique used to visualize overall cell morphology and size.Rate this question:
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- 14.
Specific organisms that are considered strict anaerobic anaerobs include:
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E.coli and Streptococus pneumoniae
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Bacteroides and klebsieella
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Fusobacterium and clostridium
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Peptostreptococus and nocardia
Correct Answer
A. Fusobacterium and clostridiumExplanation
Fusobacterium and Clostridium are considered strict anaerobic anaerobes because they cannot survive in the presence of oxygen. They are adapted to environments with low or no oxygen levels and have specific metabolic pathways that allow them to generate energy without the need for oxygen. These organisms are commonly found in the gastrointestinal tract and can cause various infections in humans.Rate this question:
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- 15.
Proved the microorganisms cause disease
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Koch
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Pasteur
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Lister
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Jenner
Correct Answer
A. KochExplanation
Koch is the correct answer because he played a significant role in proving that microorganisms cause disease. He developed several techniques and principles, known as Koch's postulates, which are still used today to identify the causative agents of infectious diseases. Koch's work on tuberculosis and cholera specifically demonstrated the link between specific microorganisms and the diseases they cause. His contributions to the field of microbiology greatly advanced our understanding of infectious diseases and paved the way for the development of effective treatments and preventive measures.Rate this question:
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- 16.
What type of media would the plate in the figure be if it allowed most all bacteria to grow, but distinguished between colonies of one organism from another?
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Enrichment
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Differential
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Selective
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Reducing
Correct Answer
A. DifferentialExplanation
The plate in the figure would be a differential media because it allows most bacteria to grow, but it also distinguishes between colonies of one organism from another. Differential media contains specific ingredients that cause different bacteria to exhibit different visible characteristics, such as color changes or formation of specific patterns, allowing for differentiation between different types of bacteria.Rate this question:
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Current Version
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Mar 22, 2023Quiz Edited by
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Jun 13, 2012Quiz Created by
Zameer_mind
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