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Chapter 1-5 Microbiology Study Guide Questions and Answers
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Chapter 1-5 Microbiology Study Guide
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Chapter 1-5 Microbiology Study GuideIn what ways are microorganisms important to humans? - answer The oxygen we
breathe is the result of microbial activities, as well as the water we drink, the health of
our animals, etc.
What is a bacterial colony and how is it formed? - answer A macroscopically visible
population of cells that is formed from a single cell that has divided many times.
How can you get a pure culture of bacteria and why are pure cultures important? -
answer Pure cultures usually come from mixed cultures and are very important because
they can be used for experiments that probe the fundamental processes of life.
Where do you find microorganisms and do they typically live in a pure culture? - answer
Microorganisms are found everywhere. Pure cultures are usually set up to perform
experiments.
What cellular structures distinguish prokaryotic and eukaryotic cells? - answer-
Eukaryotic cells contain organelles, which includes, most prominently, the DNA-
containing nucleus and also mitochondria and chloroplasts.
-Prokaryotic cells have few internal structures, they lack a nucleus, and they typically
lack organelles.
What are some differences between a cell wall and a cell membrane? - answerCell
walls are relatively permeable and much stronger than the cell membrane.
In what types of organisms would you expect to find cell walls and or cell membranes? -
answerCell walls are typically found in plant cells and most microorganisms but are not
found in animal cells.
Cell membranes can be found in all cells.
How has the Earth changed over its history? How have microorganisms contributed to
these changes? - answer80% of life's history was exclusively microbial; Cyanobacteria
provided the greatest changes because they produced oxygen
Name the three domains of life. Which of these contain eukaryotic life forms? How are
they similar and different? - answerThe three domains of life are Eukarya, Bacteria, and
Archaea. Eukarya and Archaea are more similar to each other than either is to Bacteria
despite Eukarya appearing long after.
Why were cyanobacteria so important in the evolution of life on Earth? -
answerCyanobacteria are so important to the evolution of life on earth because they are
responsible for oxygenating the earth.
, What is a genus name of a cyanobacterium and what is unique about these organisms?
- answer
How do microbes contribute to the nutrition of animals such as humans and cows? -
answerThey allow for the digestion of cellulose through fermentation in ruminant
animals. Humans rely on gut microbiomes to break down complex carbohydrates.
Describe several ways in which microorganisms are important in the food and
agricultural industries. - answerAlthough some microbes contribute to the spoilage of
food and foodborne diseases, some are important for the preservation, safety, or even
development of certain foods.
What is wastewater treatment and why is it important? - answerIt is the treatment of
water contaminated with human waste by using microbes so it can be safely reused or
returned to the environment. It is essential to sanitization and human health.
What is the difference between magnification and resolution? - answerMagnification is
the capacity of a microscope to enlarge an image. Resolution is the ability to distinguish
two objects as distinct and separate.
What is the function of staining in light microscopy? - answerThe function of staining is
to either increase the contrast or to determine which type of cell is present (gram
negative/ gram positive).
What color will a gram-negative cell be after Gram staining by the conventional method?
Gram positive? Why? - answerGram negative will be pink, while gram positive will be
purple. Gram positive is purple because it has a thicker cell wall and layer of
peptidoglycan which will keep the crystal violet dye.
What are the steps of a gram stain and the function of each reagent? - answer1. flood
heat-fixed smear with crystal violet for one minute (all cells purple)
2. Add iodine solution for one minute (all cells purple)
3. Decolorize w/ alcohol for 20 sec. (gram positive cells=purple, gram negative=
colorless)
4. counterstain with safranin for one to two minutes (gram negative now pink)
What major advantage does phase-contrast microscopy have over staining? -
answerStaining can kill cells or distort their features, so phase-contrast microscopy
allows for viewing of live specimens.
How can cells be made to fluoresce? - answerThey are made to fluoresce by
illuminating them from above with light of a single color, and filters are used so only
fluorescent light is seen. They either naturally fluoresce due to chlorophyll or artificially
fluoresce by dyes.
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