Exam (elaborations)
SCSU BIO120 Lab Exam I questions with correct answers
- Course
- Institution
SCSU BIO120 Lab Exam I questions with correct answers
[Show more]
Content preview
SCSU BIO120 Lab Exam IWho introduced the world to the existence of microbial forms of life? - correct answer ✔✔Antoni van
Leeuwenhoek
How does a brightfield microscope work? - correct answer ✔✔The specimen is illuminated by a beam of
tungsten light focused on it by a substage lens called a condenser; the result is a specimen that appears
dark against a bright background. Most brightfield observations are performed on nonliving, stained
preparations
How does a darkfield microscope work? - correct answer ✔✔The condenser directs the light obliquely so
that the light is deflected or scattered from the specimen, which then appears bright against a dark
background. Most darkfield observations are performed on living specimens.
Heat Fixation - correct answer ✔✔The rapid passage of the smear over the Bunsen burner flame to kill
off bacteria
Types of Algae - correct answer ✔✔• Euglena
• Diatoms
• Spirogyra
• Scenedesmus
• Chlamydomonas
• Volvox
Types of Protozoa - correct answer ✔✔• Paramecium
• Stylonychia
• Amoeba
• Vorticella
• Heteronema
, Brownian Movement - correct answer ✔✔When cells are not really moving on their own,but instead
appear to be moving due to vibrations and water
True Motility - correct answer ✔✔When cells are moving on their own
What is the major advantage of using living cell preparations (hanging drop or wet mount) rather than
stained preparations? - correct answer ✔✔With living cell preparations, the motility of the bacteria can
be seen, as well as the original shape and size of the bacteria, and binary fission. Staining preparations
slightly alter the bacteria
Why are living, unstained bacterial preparations more difficult to observe microscopically than stained
preparations? - correct answer ✔✔Bacteria are so small and their refractive index is close to water so
there is not much contrast between the two leaving a clear image. Staining adds contrast and makes
them easier to see. Also, because they haven't been heat-fixed, bacteria will be able to move around
making it hard to see them under the microscope
How do you distinguish between true motility and Brownian movement? - correct answer ✔✔Brownian
movement is random while true movement is purposeful; viable organisms will show purposeful
movement while suspended debris will not
During the microscopic observations of a drop of stagnant pond water, what criteria would you use to
distinguish viable organisms from nonviable suspended debris? - correct answer ✔✔Viable organisms
will move around and most have intracellular organelles
Simple Staining - correct answer ✔✔The bacterial smear is stained with a single reagent, which produces
a distinctive contrast between the organism and its background
Coccus
(Cocci pl.) - correct answer ✔✔*Spherical* shaped bacteria
Diplococcus - correct answer ✔✔Paired cocci
Streptococcus - correct answer ✔✔Chain of cocci
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller BravelRadon. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $12.99. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
67474 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now