PRACTICUM 1 STUDY GUIDE
Your exam will cover everything from week 1 through week
6. This is only a study guide. Not all of the materials you’re
responsible for are in this guide. Go over your lab manual, lab reports, handouts,
quizzes, and notes.
Week 1 covered Exercises 1 & 4
- Know the following terms: limit of resolution, parfocal
- Know how to calculate the magnification of an object
you’re viewing through the microscope.
- Know the parts of the Bright-field Light Microscope.
- Why do we use oil immersion for bacterial cultures?
- Know the three domain classification system.
- Know the different bacterial shapes and arrangement.
- These are the organisms you studied in week 1:
Micrococcus luteus-cocci, nonmotile,
Brownian movement on live cultures
Bacillus anthracis non-motile
& Bacillus subtilis-rod, motile
Nostoc-hetorocysts for N
reproduces by budding/binary fission
Paramecium-move by cilia
- Be able to recognize organisms under the microscope.
Be aware of specific structures (presence or absence of a nucleus, etc.)
- What’s the difference between a Bright-field Light
Microscope and a Phase-Contrast Microscope?
Week 2 covered Exercises 13 & 14
- What are the three physical forms of media?
- Know the differences between the types of media we
discussed (i.e. chemically defined vs. complex).
- What is sterilization? What are some of the ways we sterilize
media and materials?
- What is subculturing? What is the purpose of
- Why is aseptic technique important in lab?
- What are some of the methods we can use to maintain pure
- You studied Serratia marcescens in week 2.
What specific characteristic does this organism has that makes it easy to
Week 3 covered Exercises 7, 16, & 15
- What is a bacterial smear? What is the difference
between preparing a bacterial smear from a both culture and a solid
- Why do we have to heat-fix our bacterial smears?
- What is simple staining? What is its purpose? What’s
the difference between acidic and basic dyes? How does each one work?
- Be able to recognize the kind of stain used on a slide of
specimen (crystal violet, methylene blue, carbolfuchsin)
- What’s the purpose of the streak-plate and spread-plate
- Be able to demonstrate a streak-plate on the exam.
- What is a colony?
- The organisms you studied in week 3 are: Serratia
marcescens, Micrococcus luteus, Rhodospirillum rubrum,
Escherichia coli, Bacillus subtilis.
Week 4 covered Exercises 8, 10, 14 (part 2), & 15
- What type of stain is the Gram stain? What are the
reagents we use?
- Why do we use a mordant on the Gram stain? Know what
each reagent does.
- Know the Gram stain procedure and how it works.
- What does it mean to be gram variable?
- What type of stain is the endospore stain? What is
- Why do we use heat in the endospore stain?
- What is the medical significance of the endospore stain?
- Know the endospore stain procedure.
9. The organisms you worked
with in week 4 are: Escherichia coli (gram – rods, not an
endosporeformer), Staphylococcus epidermidis (gram + cocci), Bacillus
subtilis (rod, endosporeformer), Clostridium sporogenes ( short rod
with a central spore)
Week 5 covered Exercises 9, 11, 18
- What type of stain is the acid-fast stain? Why do we
use this stain on certain bacteria? What is unique about acid-fast
organisms? Hint: characteristic of their cell wall
- What is the medical significance of this stain?
- Know the acid-fast stain procedure. Why do we use
- What is a capsule? Why are capsules important to
- How does the capsule staining works? Hint: it’s a negative
6. What are some of the
mechanisms motile bacteria use to self propel?
- What is Brownian movement and what causes it?
- Know the following bacterial characteristics: obligate aerobes,
facultative anaerobes, obligate anaerobes, aerotolerant anaerobes,
- What are some of the ways we can determine the oxygen
requirement of microorganisms?
- The organisms you studied in week 5 are: Mycobacterium
tuberculosis (acid-fast bacterium), Klebsiella pneumoniae (a
bacterium with a capsule), Proteus vulgaris (motile, facultative
anaerobe), Bacillus subtilis ( motile, obligate aerobe), Micrococcus
luteus (nonmotile, obligate aerobe), Staphylococcus epidermidis
(nonmotile, facultative anaerobe), Clostridium sporogenes (obligate
anaerobe), Escherichia coli (facultative anaerobe)
- Be able to recognize ALL of the organisms mentioned in
this guide on a slide under a microscope, on a plate, in a tube.
Know their patterns of growth in different types of media.
Week 6 covered Exercises 19 &
- What’s the difference between the standard or viable plate
count method and the spectrophotometric (turbidemetric) analysis?
What is their purpose?
- Be able to recognize and work through a dilution
problem. Know how to calculate the CFU/ml. What does CFU stand
for and what is the concept behind it?
- What are the four phases of bacterial growth? What
are the differences between them?
- Be able to calculate the generation time from a growth
REMINDERS: You have to know
both names of the organism and underline it. Go through the demos.
* See your lab manual appendix for more dilution problems
they have answers.