MMBIO 221 TEST QUESTIONS AND ANSWERS A+
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•What Is a Microbe?
•Describe how we define a microbe, and explain why the definition is a challenge.
Microbes are small, ancient, many, and are both good and bad.
This definition is a challenge because not all microbes are small . E. coli is less then a
micrometer thick, half the biomass on earth is microbial, this is also why they are
ancient they have had time to become so diverse and evidence shows that eukaryotes
have mitochondria and chloroplasts from early life. Some useful for things like cheese
and food production and others cause disease and other problems
•Describe the three major domains of life: Archaea, Bacteria, and Eukarya.
Explain what the three domains have in common and how they differ.
Archaea and bacteria both lack a membrane enclosed nucleus which makes them both
Prokaryotes
Eukaryotes: these are cells with a true nucleus
•Define viruses, and explain how they relate to living cells.
These are acellular, but they perform many functions of living organisms . Viruses have
protein coat with RNA or DNA core, need living cells to replicate
•Provide examples of how microbes are small, many, ancient, and good and bad.
Small: you need a microscope to see them most of the time; but they are still complex
and have great capabilities
Many: there are more microbes on humans than human cells; they compose half the
biomass on earth;
Ancient: they have diversified greatly; occupy the most branches on the tree of life;
mitochondira evolved from prokaryotes
Define the germ theory of disease.
The germ theory of disease states that some diseases are caused by microorganisms.
These small organisms, too small to see without magnification, invade humans,
animals, and other living hosts. Their growth and reproduction within their hosts can
cause a disease.
•Explain how Louis Pasteur contributed to the development of Microbiology
Further work led Pasteur to come up with the idea of partial sterilization to keep various
beverages from spoilage (we call this process pasteurization).
Explain how Koch's postulates can show that a specific kind of microbe causes a
disease.
The microorganism must be found in abundance in all organisms suffering from the
disease, but should not be found in healthy organisms.
1. The microorganism must be isolated from a diseased organism and grown in pure
culture.
2. The cultured microorganism should cause disease when introduced into a healthy
organism.
3. The microorganism must be reisolated from the inoculated, diseased experimental
host and identified as being identical to the original specific causative agent.
GRADED. Buy Quality Materials!
•What Is a Microbe?
•Describe how we define a microbe, and explain why the definition is a challenge.
Microbes are small, ancient, many, and are both good and bad.
This definition is a challenge because not all microbes are small . E. coli is less then a
micrometer thick, half the biomass on earth is microbial, this is also why they are
ancient they have had time to become so diverse and evidence shows that eukaryotes
have mitochondria and chloroplasts from early life. Some useful for things like cheese
and food production and others cause disease and other problems
•Describe the three major domains of life: Archaea, Bacteria, and Eukarya.
Explain what the three domains have in common and how they differ.
Archaea and bacteria both lack a membrane enclosed nucleus which makes them both
Prokaryotes
Eukaryotes: these are cells with a true nucleus
•Define viruses, and explain how they relate to living cells.
These are acellular, but they perform many functions of living organisms . Viruses have
protein coat with RNA or DNA core, need living cells to replicate
•Provide examples of how microbes are small, many, ancient, and good and bad.
Small: you need a microscope to see them most of the time; but they are still complex
and have great capabilities
Many: there are more microbes on humans than human cells; they compose half the
biomass on earth;
Ancient: they have diversified greatly; occupy the most branches on the tree of life;
mitochondira evolved from prokaryotes
Define the germ theory of disease.
The germ theory of disease states that some diseases are caused by microorganisms.
These small organisms, too small to see without magnification, invade humans,
animals, and other living hosts. Their growth and reproduction within their hosts can
cause a disease.
•Explain how Louis Pasteur contributed to the development of Microbiology
Further work led Pasteur to come up with the idea of partial sterilization to keep various
beverages from spoilage (we call this process pasteurization).
Explain how Koch's postulates can show that a specific kind of microbe causes a
disease.
The microorganism must be found in abundance in all organisms suffering from the
disease, but should not be found in healthy organisms.
1. The microorganism must be isolated from a diseased organism and grown in pure
culture.
2. The cultured microorganism should cause disease when introduced into a healthy
organism.
3. The microorganism must be reisolated from the inoculated, diseased experimental
host and identified as being identical to the original specific causative agent.
