Questions and Answers
Which of the following items will you need to make a wet mount? (Select all that apply)
What is the advantage of using a wet mount?
The motility of a specimen can be viewed under a microscope; the specimen can be viewed as living cells.
Place the steps in the correct order for preparing and observing a wet mount.
Obtain a clean slide and cover slip. = 1 Using a transfer pipette, obtain a drop of specimen and place onto the center of the slide. = 2 Carefully place the cover slip over the drop of specimen. = 3 Observe preparation under the 10X objective lens. = 4 Observe preparation under the 40X objective lens. = 5
A wet mount requires the addition of certain dyes and cell fixatives approximately 12 hours before viewing the specimen.
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What does the term motile mean?
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What are three advantages of using the Wet Mount Technique?
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Treating the work area with disinfectant will kill all forms of microbes.
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The application of a disinfectant to the lab bench ensures that the work area is sterile before the laboratory exercise is started.
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Inoculated plates are incubated upside down to prevent the dripping of condensate onto the surface of the agar.
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Microorganisms are found in nearly every environment and are said to be?
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Which term refers to the introduction of unwanted microorganisms?
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Indicate the sites where microorganisms are likely to be found. (Select all that apply)
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Which of the following conditions may increase the level of microbial contamination in an environment? (Select all that apply)
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What incubation temperature is preferred for the growth of most medically important bacteria? (Select all that apply)
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Indicate the statements that correctly describe microbial colonies. (Select all that apply)
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You have cultured several different objects and surfaces in the environment. Which of the following indicates a more abundant bacterial population?
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Which of the steps described here prevents the contamination of just-washed hands?
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What environmental factors will affect the type of microbial growth?
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Process of adding a microbe to a growth material.
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The material which provides the nutrients for growth is called?
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To cultivate (verb) or observable growth (noun) is referred to as?
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How is an inoculating loop or needle sterilized prior to use?
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Why is the mouth of a culture tube passed through the Bunsen burner flame after removing and before replacing the cap?
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To retrieve a sample from a culture tube with an inoculating loop, the cap of the tube is?
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After inoculating and incubating an agar slant from a pure broth culture of a bacterial species such as E.coli, which of the following would indicate an unsuccessful aseptic transfer? (Select all that apply)
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Which of the following may indicate that you have correctly transferred an organism from a broth to a slant? (Select all that apply)
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The goal of _________________ technique is to minimize the contamination of both original and newly inoculated cultures as well as to protect the laboratory worker from contamination.
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Which types of culture media are solid? (Select all that apply)
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Media in slants and Petri dishes is solidified by the addition of?
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What type of medium provides the best opportunity for growing and observing the morphology of isolated colonies?
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If you transfer bacterial growth from a broth to an agar plate but nothing grows after incubation, what may have occurred?
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Observation of a broth after transfer can show whether or not contamination has occurred.
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A substance used to support the growth of microbial life is referred to as a?
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Study Notes
Wet Mount Preparation
- Necessary items for creating a wet mount include transfer pipette, clean slide, tweezers, and cover slip.
- The wet mount technique allows for viewing the motility of living cells under a microscope, making it valuable for observing live specimens.
- Steps for preparing a wet mount: Obtain a clean slide and cover slip, use a pipette for a drop of specimen, place the cover slip on top, and observe first under 10X and then under 40X objective lenses.
Safety and Contamination
- Wet mounts do not require dyes or cell fixatives applied 12 hours prior to observation.
- Disinfectants do not kill all forms of microbes, and application does not guarantee a sterile work area.
- True inoculated plates should be incubated lid-down to prevent condensation from contaminating the agar surface.
Microbial Life and Presence
- Microorganisms are ubiquitous, found in nearly every environment.
- Contamination refers to the introduction of unwanted microorganisms, which can occur frequently in common laboratory sites such as air, benches, hands, and keyboards.
- Conditions such as warm temperatures, moisture, and contact with humans or animals can increase microbial contamination levels.
Growth Conditions
- Most medically important bacteria prefer incubation at 37°C, equivalent to 98°F.
- Microbial colonies are visible accumulations on agar surfaces; isolated colonies descend from a single cell.
- For a successful transfer to an agar slant, a clean inoculating loop/needle is essential and must be sterilized using a Bunsen burner flame.
Inoculation and Culture
- The process of adding microorganisms to a growth medium is termed inoculation; the nutrient-rich material is referred to as culture medium.
- Cultures are used to cultivate organisms, and the visible growth is termed culture.
- Agar plates and slants are solid culture media, which are preferred for observing isolated colonies.
Aseptic Technique
- Aseptic techniques aim to minimize contamination in cultures and protect laboratory personnel.
- Transferring organisms aseptically involves techniques to ensure cleanliness and avoid introducing contaminants from the environment.
Observations and Errors
- If an agar plate shows no growth after transferring from broth, it may indicate issues such as overheating the loop, impacting bacterial viability.
- Accurate results following an inoculation include observing uniform cell color and morphology across slants, indicating a successful transfer.
Miscellaneous
- Observation of broth cultures cannot reliably indicate contamination without further tests.
- The culture medium comprises all substances required to support microbial life growth.
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Description
This quiz covers the essential techniques for preparing a wet mount, including the necessary items and steps for observation. It also emphasizes the importance of safety and contamination management while working with microbial life. Understand the best practices for observing live specimens under a microscope.
