MIBO 3500 Exam 1 (Jennifer Walker) UPDATED ACTUAL Questions And Correct
Answers
Terms in this set (110)
What is a microbe? an organism that requires a microscope to be seen. Each microbe contains in its
genome the capacity to reproduce its own kind.
The three domains of life? Analysis of DNA sequences reveals the ancient divergence of three domains of
living organisms: Bacteria and Archea (Prokaryotes) and eukarya (eukaryotes).
What data was used by Carl Woese to differ organisms Woese used 16s rRNA comparisons in organisms to classify into 3 domains.
into the domains?
What are some microbial contradictions? 1. Supersize microbial cells (Thiomargarita namibiensis)
2. Microbial communities (biofilms -- plaque on teeth)
3. Virus sizes
What is a genome? The total genetic information contained in an organism's CHROMOSOMAL DNA.
What is a metagenome? The collection of sequences taken directly from the ENVIRONMENT.
-- Acquire environmental sample
-- Lise the cells
-- cypher through DNA
What does metagenome analysis allow? Allows for the discovery of new microbes without having to isolate and grow
them in vitro.
What ways do you think microbes have affected human TB from World War I and II. Aids --> sexual contraception, and Influenza and
history? Amoxicillin.
Why did two-thirds of Saiga antelope drop dead? A bacteria called Pastuerella multocida type B. They normally live harmlessly in
the long nose of the antelope, but it suddenly invaded the rest of the body.
Germ theory of disease (Robert Koch) Established a causative link between an infectious agent and a disease. -- Koch's
postulates
-- To prove a particular bacterium caused a specific disease, a PURE culture of
microorganisms was needed.
Koch's first Postulate The microbe is found in all cases of the disease but is absent from healthy
individuals. (Used rabbits as lab rats)
Koch's second Postulate The microbe is isolated from the diseased host and grown in pure culture.
Koch's third Postulate When the microbe is introduced into a healthy, susceptible host, the same disease
occurs.
Koch's fourth Postulate The same strain of microbe is obtained from the newly diseased host.
, What type of microbe induced diseases may NOT be A prion infection "Mad Cow" disease can not use Koch's Postulates.
identified through Koch's Postulates?
Who used Koch's Postulates to identify gastric ulcers Drs. Barry Marshall and Robyn Warren followed Koch's postulates to prove
were caused by Helicobacter pylori? Helicobacter pylori was the pathogen that induced gastric ulcers (1985)
--Awarded Nobel Price in 2005
What does analysis of 16s rRNA sequence show? It shows that Archaea are as distant from bacteria as from eukaryotes
What is Resolution? It is the smallest distance by which two objects can be separated and still be
distinguished.
--the resolution of the human retina is about 150 (1/7mm)
What determines the function of a microbe? Structure of the microbe
What are the common shapes of bacteria? Bacillus (long rod shape), spirochete (corkscrew), Cocci (circular, usually in pairs,
grow together)
What is Bright-field Microscopy? Generates a dark image of an object over a light background.
-To increase resolution
--Use shorter wavelength
--Lessen contrast
--Use immersion oil (The use of oil at 100x helps minimize refraction and increase
resolution)
What is fixation? Cells are made to adhere to a slide in a fixed position
What is staining? Most stains have conjugated double bonds or aromatic rings, and one or more
positive charges to adhere to cells.
What does a simple stain do? It adds dark color specifically to cells, but not to the external medium or
surrounding tissue.
What does a differential stain do? It stains one kind of cell but not the other.
--Gram stain
Does Gram-positive bacteria retain crystal violet stain? Gram-positive bacteria DOES retain the crystal violet stain because of their thicker
cell wall.
Does Gram-negative bacteria retain crystal violet stain? Gram-negative bacteria DOES NOT retain crystal violet, cell walls are much
thinner.
What does acid-fast stain do? It uses carbolfuchsin to stain Mycobacterium species.
What does spore stain do? Uses malachite green to detect spores of Bacillus and Clostridium
What does negative stain do? It colors the background, which makes capsules more visible. (Like a clear bubble
around them)
Answers
Terms in this set (110)
What is a microbe? an organism that requires a microscope to be seen. Each microbe contains in its
genome the capacity to reproduce its own kind.
The three domains of life? Analysis of DNA sequences reveals the ancient divergence of three domains of
living organisms: Bacteria and Archea (Prokaryotes) and eukarya (eukaryotes).
What data was used by Carl Woese to differ organisms Woese used 16s rRNA comparisons in organisms to classify into 3 domains.
into the domains?
What are some microbial contradictions? 1. Supersize microbial cells (Thiomargarita namibiensis)
2. Microbial communities (biofilms -- plaque on teeth)
3. Virus sizes
What is a genome? The total genetic information contained in an organism's CHROMOSOMAL DNA.
What is a metagenome? The collection of sequences taken directly from the ENVIRONMENT.
-- Acquire environmental sample
-- Lise the cells
-- cypher through DNA
What does metagenome analysis allow? Allows for the discovery of new microbes without having to isolate and grow
them in vitro.
What ways do you think microbes have affected human TB from World War I and II. Aids --> sexual contraception, and Influenza and
history? Amoxicillin.
Why did two-thirds of Saiga antelope drop dead? A bacteria called Pastuerella multocida type B. They normally live harmlessly in
the long nose of the antelope, but it suddenly invaded the rest of the body.
Germ theory of disease (Robert Koch) Established a causative link between an infectious agent and a disease. -- Koch's
postulates
-- To prove a particular bacterium caused a specific disease, a PURE culture of
microorganisms was needed.
Koch's first Postulate The microbe is found in all cases of the disease but is absent from healthy
individuals. (Used rabbits as lab rats)
Koch's second Postulate The microbe is isolated from the diseased host and grown in pure culture.
Koch's third Postulate When the microbe is introduced into a healthy, susceptible host, the same disease
occurs.
Koch's fourth Postulate The same strain of microbe is obtained from the newly diseased host.
, What type of microbe induced diseases may NOT be A prion infection "Mad Cow" disease can not use Koch's Postulates.
identified through Koch's Postulates?
Who used Koch's Postulates to identify gastric ulcers Drs. Barry Marshall and Robyn Warren followed Koch's postulates to prove
were caused by Helicobacter pylori? Helicobacter pylori was the pathogen that induced gastric ulcers (1985)
--Awarded Nobel Price in 2005
What does analysis of 16s rRNA sequence show? It shows that Archaea are as distant from bacteria as from eukaryotes
What is Resolution? It is the smallest distance by which two objects can be separated and still be
distinguished.
--the resolution of the human retina is about 150 (1/7mm)
What determines the function of a microbe? Structure of the microbe
What are the common shapes of bacteria? Bacillus (long rod shape), spirochete (corkscrew), Cocci (circular, usually in pairs,
grow together)
What is Bright-field Microscopy? Generates a dark image of an object over a light background.
-To increase resolution
--Use shorter wavelength
--Lessen contrast
--Use immersion oil (The use of oil at 100x helps minimize refraction and increase
resolution)
What is fixation? Cells are made to adhere to a slide in a fixed position
What is staining? Most stains have conjugated double bonds or aromatic rings, and one or more
positive charges to adhere to cells.
What does a simple stain do? It adds dark color specifically to cells, but not to the external medium or
surrounding tissue.
What does a differential stain do? It stains one kind of cell but not the other.
--Gram stain
Does Gram-positive bacteria retain crystal violet stain? Gram-positive bacteria DOES retain the crystal violet stain because of their thicker
cell wall.
Does Gram-negative bacteria retain crystal violet stain? Gram-negative bacteria DOES NOT retain crystal violet, cell walls are much
thinner.
What does acid-fast stain do? It uses carbolfuchsin to stain Mycobacterium species.
What does spore stain do? Uses malachite green to detect spores of Bacillus and Clostridium
What does negative stain do? It colors the background, which makes capsules more visible. (Like a clear bubble
around them)
