Jensara sp07

Microbiology 251

Practicum 1 study guide

This study guide is to aid you in your studies. This guide may not cover all of the information you will need to know for the exam. Be sure to read all of the labs and understand the importance of the procedures described.

Week 1

  1. Know all parts of the microscope. Understand the function of each part of the microscope.
  2. Know how to calculate the magnification of an object viewed in a microscope.
  3. Know the definition of the limit of resolution and a parfocal lens system.
  4. What is the purpose of an oil immersion lens and its importance for viewing bacterial cultures.
  5. Know the difference between bright-field light microscopes and phase-contrast microscopes.
  6. Know the 3 domain classification system.
  7. know the bacterial shapes and arrangements
  8. In week 1 you viewed Bacillus subtilis, Staphylococcus epidermidis, Nostoc, Saccharomyces cerevisiae, Spirillum volutans,, Amoeba proteus, Euglena and Paramecium. Know the description of these organisms (domain, shape, movement, special structures, etc.) Be able to recognize these organisms under the microscope.

Week 2

  1. What are the 3 physical forms of media?
  2. Know the difference between chemically defined and complex media?
  3. What is sterilization? What are some methods of sterilization?
  4. What is sub-culturing? What is the purpose of sub-culturing?
  5. Why is aseptic technique important?
  6. What are some of the methods used to maintain pure cultures?
  7. In week 2 you viewed Serratia marcescens. You need to know the specific characteristics used to identify this organism.

Week 3

  1. What is a bacterial smear? What is the difference between preparing a bacterial smear from a broth culture vs. a solid medium?
  2. What is the purpose of heat fixing when preparing a bacterial smear?
  3. What is simple staining? What is the purpose of simple staining? What is the difference between acidic and basic dyes? How do acidic and basic dyes work?
  4. What’s the purpose of the spread-plate techniques?
  5. What is a colony?
  6. In week 3 you studied Serratia marcescens, Micrococcus luteus, Escherichia coli, and Bacillus subtilis.

Week 4

  1. What’s the purpose of the streak-plate
  2. Be able to demonstrate the streak plate technique.
  3. In week 4 you worked with Bacillus subtilis, Escherichia coli, and Micrococcus luteus.

Week 5

  1. What is a differential stain? What are some examples of differential stains?
  2. What type of stain is the gram stain? What are the reagents used?
  3. Know the gram stain procedure?
  4. What does gram variable mean?
  5. What is a structural stain?
  6. What is an endospore? When is it formed? What type of stain is the endospore stain?
  7. What is the medical application of endospore stain?
  8. Know the endospore stain procedure.
  9. In week 5 you worked with Escherichia coli(gram - rod), Staphylococcus epidermidis(gram + cocci), Bacillus subtilis(rod, endosporeformer), Micrococcus luteus, Clostridium sporogenes(short rod with a central endospore).

Week 6

  1. What are some mechanisms of self propulsion for bacteria?
  2. What is Brownian movement? What causes Brownian movement?
  3. What type of stain is the acid fast stain? Why is the acid fast stain used? What characteristics do acid fast bacteria possess?
  4. What is the medical application of the acid fast stain?
  5. Why is heat used in the acid fast stain?
  6. Know the acid fast staining procedure.
  7. What is a capsule? Why are they important to bacteria?
  8. What type of stain is the capsule stain?
  9. Know the different oxygen requirements for bacteria.
  10. How do you determine the oxygen requirements of bacteria?
  11. in week 5 you worked with Mycobacterium tuberculosis (acid fast), Klebsiella pnuemoniae (capsule), Bacillus subtilis (motile, obligate aerobe), Micrococcus luteus (non-motile, obligate aerobe), Staphylococcus epidermidis (non-motile, facultative anaerobe), Clostridium sporogenes (obligate anaerobe) and Escherichia coli (facultative anaerobe)
  12. Be able to recognize all of the organisms under a microscope.

Week 7

  1. What is the difference between the standard or viable plate count method and the spectrophotometric analysis? What is the purpose of these analyses?
  2. What does CFU stand for? What is a CFU
  3. Be able to complete a serial dilution problem. There are a few sample problems beginning on page 425 in your lab manual so you may practice.
  4. What are the 4 phases of bacterial growth? What bacterial activity is occurring in each phase?
  5. Be able to calculate the generation time from a growth curve.

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