CHAPTER 1 History of Microbiology
1) Antoni van Leeuwenhoek was the first person in history to - C) view microorganisms and
record these observations.
1) Microbiologists study only single-celled organisms. - FALSE
1) The amateur scientist (Koch/Leeuwenhoek/Pasteur) made his own microscopes and first
reported the existence of microbes. - Leeuwenhoek
1) You are a young scientist who has just learned about one of the hot topics in microbiology,
biofilms. One aspect of the interest in biofilms is that the microbes living within biofilms appear
to behave and function differently from their counterparts not living in a biofilm. Devise a way to
explore the idea. (Do not focus on the technical details of how this might be accomplished.) -
Many answers are possible. A good answer should have a clear statement of hypothesis and an
experimental design that reflects the hypothesis and will provide interpretable quantitative
results. An excellent answer may include projections of possible outcomes and/or alternative
hypotheses.
2) A microbe with a cell wall and no internal membrane enclosing the DNA is a prokaryote. -
TRUE
2) The (alga/fungi/protozoa) are non-motile eukaryotes with cell walls that are not
photosynthetic and may be multicellular. - fungi
2) Use the basic steps of the scientific method to describe Pasteur's experiments to investigate
spontaneous generation. - The observation that life seemed to appear from non-life led some
scientists to believe in the theory of spontaneous generation. However, Pasteur among others
believed in biogenesis: that life must come from life. The question Pasteur hoped to answer was
"Where do microbes come from?" (step 1). Pasteur's hypothesis (step 2) was that the "parents"
of microbes were present in the air on dust particles. In his experiments (step 3) he used swan-
necked flasks, which were designed to prevent microbes from entering the sterile broth inside
them. He observed that the broth remained sterile in the control flask even though air could
,move into and out of the flask. The experimental flasks were also swan-necked, but they were
tilted to allow the dust that had settled to enter the flask. The control flasks stayed sterile, and
the experimental flasks became cloudy. These observations led Pasteur to accept his
hypothesis (step 4). He concluded that the microbes came from the dust and that spontaneous
generation was therefore not a valid theory.
2) Which of the following microbes are likely to be the swiftly moving "animalcules" observed by
Leeuwenhoek in pond water? - B) protozoa
3) A cell that contains a nucleus is called a(n) (prokaryotic/archaeal/eukaryotic) cell. - eukaryotic
3) Biotechnology can be said to have ancient roots. Explain. - Biotechnology is the use of
microbes to yield beneficial products. Humans have used microbes to their benefit for millennia
in producing beer and wine, which were often safer to drink than the available water, and in
preserving foods. Examples of the latter include the production of wine, which essentially
preserved fruit juices, and of cheese and yogurt, which extended the storage life of milk
products. Soy sauce and other fermented sauces were also preserved by fermentation and
were later shown to enhance the flavors of certain foods.
3) Lazzaro Spallanzani was the first scientist to provide evidence disproving the spontaneous
generation of microorganisms. - TRUE
3) Which of the following statements about fungi is INCORRECT? - D) Fungi are photosynthetic.
4) Explain how the discipline of biochemistry grew out of the science of microbiology. - Some of
the first experiments in biochemistry are attributed to Louis Pasteur in his research on the
causes of fermentation. His research was extended by Eduard Buchner, who showed that
enzymes produced by microbial cells are responsible for the phenomenon of fermentation.
Later, in the early 20th century, Kluyver and van Niel advocated the use of microbes in research
on basic biochemical reactions, which they maintained are common to all living things. Further
advances in biochemistry were made as microbiologists such as Beadle and Tatum and Avery
and his colleagues explored the nature of the genetic material and its function using
microorganisms as model systems.
, 4) Louis Pasteur is considered the Father of Microbiology because of the many carefully
conducted experiments and observations he made with microbes. - TRUE
4) The production of wine from grape juice is the result of
(metabolism/fermentation/abiogenesis). - fermentation
4) Which of the following is an accurate description of viruses? - E) They are acellular obligatory
parasites.
5) Fermentation requires the presence of living cells. - FALSE
5) Recent news stories have reported on the "microbiome" of the human body. The reports
include statements about the abundance of the microbes in and on the human body ("They
outnumber our cells 10 to 1") and that most of these microbes are unknown to science. Discuss
how microbiologists can have confidence in these apparently conflicting statements. - Molecular
techniques have advanced to the point that it is possible to detect and visualize microorganisms
without having to isolate them in the lab. DNA sequence detection techniques in particular are
useful for identifying the presence of microbes that cannot be isolated in the lab (are
"unculturable"). This in turn has made it possible to detect the presence of many previously
unsuspected microbes. Some of the techniques also provide a means of roughly quantifying the
numbers of each type of microbe. Thus it is possible for scientists to confidently discuss the
huge numbers of microbes resident in and on the human body without having to isolate and
grow each type.
5) Spallanzani's experiments contradicted the experiments of (Needham/Redi/Pasteur) on
spontaneous generation. - Needham
5) Which of the following is an INCORRECT pairing? - A) protozoa; multicellular
6) A scientist conducts experiments to test a(n) (observation/hypothesis/theory). - hypothesis
6) A tiny (less than 2 micrometers) new organism is discovered living in a boiling hot "mud pot"
(a type of mud spring). It is most likely a member of the - B) archaea.
1) Antoni van Leeuwenhoek was the first person in history to - C) view microorganisms and
record these observations.
1) Microbiologists study only single-celled organisms. - FALSE
1) The amateur scientist (Koch/Leeuwenhoek/Pasteur) made his own microscopes and first
reported the existence of microbes. - Leeuwenhoek
1) You are a young scientist who has just learned about one of the hot topics in microbiology,
biofilms. One aspect of the interest in biofilms is that the microbes living within biofilms appear
to behave and function differently from their counterparts not living in a biofilm. Devise a way to
explore the idea. (Do not focus on the technical details of how this might be accomplished.) -
Many answers are possible. A good answer should have a clear statement of hypothesis and an
experimental design that reflects the hypothesis and will provide interpretable quantitative
results. An excellent answer may include projections of possible outcomes and/or alternative
hypotheses.
2) A microbe with a cell wall and no internal membrane enclosing the DNA is a prokaryote. -
TRUE
2) The (alga/fungi/protozoa) are non-motile eukaryotes with cell walls that are not
photosynthetic and may be multicellular. - fungi
2) Use the basic steps of the scientific method to describe Pasteur's experiments to investigate
spontaneous generation. - The observation that life seemed to appear from non-life led some
scientists to believe in the theory of spontaneous generation. However, Pasteur among others
believed in biogenesis: that life must come from life. The question Pasteur hoped to answer was
"Where do microbes come from?" (step 1). Pasteur's hypothesis (step 2) was that the "parents"
of microbes were present in the air on dust particles. In his experiments (step 3) he used swan-
necked flasks, which were designed to prevent microbes from entering the sterile broth inside
them. He observed that the broth remained sterile in the control flask even though air could
,move into and out of the flask. The experimental flasks were also swan-necked, but they were
tilted to allow the dust that had settled to enter the flask. The control flasks stayed sterile, and
the experimental flasks became cloudy. These observations led Pasteur to accept his
hypothesis (step 4). He concluded that the microbes came from the dust and that spontaneous
generation was therefore not a valid theory.
2) Which of the following microbes are likely to be the swiftly moving "animalcules" observed by
Leeuwenhoek in pond water? - B) protozoa
3) A cell that contains a nucleus is called a(n) (prokaryotic/archaeal/eukaryotic) cell. - eukaryotic
3) Biotechnology can be said to have ancient roots. Explain. - Biotechnology is the use of
microbes to yield beneficial products. Humans have used microbes to their benefit for millennia
in producing beer and wine, which were often safer to drink than the available water, and in
preserving foods. Examples of the latter include the production of wine, which essentially
preserved fruit juices, and of cheese and yogurt, which extended the storage life of milk
products. Soy sauce and other fermented sauces were also preserved by fermentation and
were later shown to enhance the flavors of certain foods.
3) Lazzaro Spallanzani was the first scientist to provide evidence disproving the spontaneous
generation of microorganisms. - TRUE
3) Which of the following statements about fungi is INCORRECT? - D) Fungi are photosynthetic.
4) Explain how the discipline of biochemistry grew out of the science of microbiology. - Some of
the first experiments in biochemistry are attributed to Louis Pasteur in his research on the
causes of fermentation. His research was extended by Eduard Buchner, who showed that
enzymes produced by microbial cells are responsible for the phenomenon of fermentation.
Later, in the early 20th century, Kluyver and van Niel advocated the use of microbes in research
on basic biochemical reactions, which they maintained are common to all living things. Further
advances in biochemistry were made as microbiologists such as Beadle and Tatum and Avery
and his colleagues explored the nature of the genetic material and its function using
microorganisms as model systems.
, 4) Louis Pasteur is considered the Father of Microbiology because of the many carefully
conducted experiments and observations he made with microbes. - TRUE
4) The production of wine from grape juice is the result of
(metabolism/fermentation/abiogenesis). - fermentation
4) Which of the following is an accurate description of viruses? - E) They are acellular obligatory
parasites.
5) Fermentation requires the presence of living cells. - FALSE
5) Recent news stories have reported on the "microbiome" of the human body. The reports
include statements about the abundance of the microbes in and on the human body ("They
outnumber our cells 10 to 1") and that most of these microbes are unknown to science. Discuss
how microbiologists can have confidence in these apparently conflicting statements. - Molecular
techniques have advanced to the point that it is possible to detect and visualize microorganisms
without having to isolate them in the lab. DNA sequence detection techniques in particular are
useful for identifying the presence of microbes that cannot be isolated in the lab (are
"unculturable"). This in turn has made it possible to detect the presence of many previously
unsuspected microbes. Some of the techniques also provide a means of roughly quantifying the
numbers of each type of microbe. Thus it is possible for scientists to confidently discuss the
huge numbers of microbes resident in and on the human body without having to isolate and
grow each type.
5) Spallanzani's experiments contradicted the experiments of (Needham/Redi/Pasteur) on
spontaneous generation. - Needham
5) Which of the following is an INCORRECT pairing? - A) protozoa; multicellular
6) A scientist conducts experiments to test a(n) (observation/hypothesis/theory). - hypothesis
6) A tiny (less than 2 micrometers) new organism is discovered living in a boiling hot "mud pot"
(a type of mud spring). It is most likely a member of the - B) archaea.
