Page |1
BISC 261: Microbiology Exam I 2025
|QUESTIONS AND DETAILED
ANSWERS (100% ACCURATE)
|ALREADY PASSED.
RATED
false
(T/F) extant microorganisms are organisms from the fossil record that are no longer present
on earth today.
microbiology is the study of microscopic organisms, the tools, and methods to study
these microorganisms. these microorganisms includes fungi, bacteria, viruses, etc.
define the term microbiology.
carl worse began the comparison of rRNA nucleic acid sequences in the 1970s. this was
essential and showed that there are two very different groups of organisms with
prokaryotic cell architecture which included bacteria and archaea. later studies on RNA
comparison show that Protista is not a cohesive taxonomic unit and that should be
divided into the third kingdom: eukarya.
explain carl woe's contributions in establishing the three-domain system for classifying
cellular life.
Thomas Chech discovered a molecule and a protist that has catalytic activity. other
catalytic RNA molecules have been discovered including an RNA found in a ribosome
that forms peptide bonds which are the bonds that hold amino acids together. Amino
acids are the building blocks of proteins. When he discovered this it suggested that RNA
was able to copy an expressed genetic expression. the RNA was also able to catalyze
, Page |2
chemical reactions. This led to the hypothesis that life on earth began with a simple
RNA molecule.
explain the "RNA world hypothesis." what discoveries lead them to propose this hypothesis?
Koch's postulates show the relationship between microorganisms and a specific disease.
Koch's postulates have been used to discover disease-causing microorganisms for
various infectious diseases. the first step in his postulates is the microorganism must be
present in every case of the disease but absent from healthy organisms. the second step
is that the microorganism that is suspected of causing the disease must be isolated and
grown in pure culture. the third step is that the same disease must result when the
isolated microorganism is inoculated into a healthy host. the fourth step is that the same
microorganism must be isolated again from the disease host. Koch's postulates do not
always work. especially in the case that some human diseases lack an appropriative
animal model so the postulates cannot be fully met.
Koch's postulates: what is its purpose, when is it used, what are the steps, and when does it
not work?
viruses, viroids, satellites, and prions are not included in the three-domain system
because only cellular organisms and organisms that are able to reproduce are included
in the taxonomic system. cellular organisms that cannot reproduce, such as viruses, are
not included. viruses, viroids, satellites, and prions are all organisms that lack certain
traits to be included in the three domain system. viruses and prions do not contain
certain cells, and they do not have an energy metabolism system. another factor that
separates them from the three domain system is that they do not contain cell organelles.
these are why viruses, viroid, satellites, and prions are not included in the three-domain
system.
why aren't viruses, viroids, satellites, and prions included in the tree domain system? (your
answer must give some level of detail to help explain your answer).
in the beginning, the term prokaryote was used to imply a close evolutionary
relationship between bacteria and archaea. the term prokaryote is no longer used in this
context because of the vast diversity between bacteria and archaeal. when the term
prokaryote was first used it was believed that prokaryotes lack a nucleus, which is not
the case since some bacteria contain a nucleus-like structure. this is why the term
, Page |3
prokaryote us considered an adequate descriptor of the organisms found in the archaeal
and bacterial domains.
why is the term prokaryote considered an inadequate descriptor by some microbiologists for
organisms found in the archaea and bacterial domains?
bacteria have peptidoglycan in cell walls and they have a single origin of replication.
archaea have multiple origins of replication and are composed of more than one type of
flagellin. eukaryotic cells have true membrane-bound nuclei and other organelles, have
DNA complexes with histones, have a nucleus, and contain a cytoskeleton. Three
structures that these domains all have in common are they contain membranes, DNA,
and ribosomes.
compare and contrast bacterial, archaeal, and eukaryotic cells. list three major differences
between them. then list three structures or properties they have in common.
four eukaryotic cells have membrane-bound organelles which include a membrane-
bound nucleus. bacteria and archaeal cells do not contain membrane-bound nuclei.
bacteria do have a nucleus-like structure that is not membrane-bound, whereas archaea
has no nucleus-like structure. this is the reason that the roles of the three different
domains' membranes are different.
the most obvious difference between eukaryotic bacteria and archaeal cells is in there use of
membranes. specifically, compare the roles of bacteria and archaeal plasma membrane with
those of the organelle membranes in eukaryotes.
fungi
Protists contain all of the following forms of life except
A. protozoa.
B. fungi.
C. slime molds.
D. algae.
eukaryotes
Cells with a relatively complex morphology that have a true membrane-delimited nucleus are
called
A. prokaryotes.
, Page |4
B. eukaryotes.
C. urkaryotes.
D. nokaryotes.
prokaryotes
Cells with a relatively simple cell morphology that do not have a true membrane-delimited
nucleus are called
A. prokaryotes.
B. eukaryotes.
C. urkaryotes.
D. nokaryotes.
woese
The ribosomal RNA studies that led to the division of prokaryotic organisms into the Bacteria
and the Archaea were begun by
A. Pasteur.
B. Woese.
C. Needham.
D. Watson.
cells lack response to external environment
Definition of life includes all of the following except
A. cells maintain internal order.
B. cells use energy and have a metabolism.
C. cells reproduce.
D. cells lack response to external environment.
both catalysts and structural elements
Proteins function in modern cells as
A. catalysts.
B. hereditary information.
C. structural elements.
D. both catalysts and structural elements.
protein
BISC 261: Microbiology Exam I 2025
|QUESTIONS AND DETAILED
ANSWERS (100% ACCURATE)
|ALREADY PASSED.
RATED
false
(T/F) extant microorganisms are organisms from the fossil record that are no longer present
on earth today.
microbiology is the study of microscopic organisms, the tools, and methods to study
these microorganisms. these microorganisms includes fungi, bacteria, viruses, etc.
define the term microbiology.
carl worse began the comparison of rRNA nucleic acid sequences in the 1970s. this was
essential and showed that there are two very different groups of organisms with
prokaryotic cell architecture which included bacteria and archaea. later studies on RNA
comparison show that Protista is not a cohesive taxonomic unit and that should be
divided into the third kingdom: eukarya.
explain carl woe's contributions in establishing the three-domain system for classifying
cellular life.
Thomas Chech discovered a molecule and a protist that has catalytic activity. other
catalytic RNA molecules have been discovered including an RNA found in a ribosome
that forms peptide bonds which are the bonds that hold amino acids together. Amino
acids are the building blocks of proteins. When he discovered this it suggested that RNA
was able to copy an expressed genetic expression. the RNA was also able to catalyze
, Page |2
chemical reactions. This led to the hypothesis that life on earth began with a simple
RNA molecule.
explain the "RNA world hypothesis." what discoveries lead them to propose this hypothesis?
Koch's postulates show the relationship between microorganisms and a specific disease.
Koch's postulates have been used to discover disease-causing microorganisms for
various infectious diseases. the first step in his postulates is the microorganism must be
present in every case of the disease but absent from healthy organisms. the second step
is that the microorganism that is suspected of causing the disease must be isolated and
grown in pure culture. the third step is that the same disease must result when the
isolated microorganism is inoculated into a healthy host. the fourth step is that the same
microorganism must be isolated again from the disease host. Koch's postulates do not
always work. especially in the case that some human diseases lack an appropriative
animal model so the postulates cannot be fully met.
Koch's postulates: what is its purpose, when is it used, what are the steps, and when does it
not work?
viruses, viroids, satellites, and prions are not included in the three-domain system
because only cellular organisms and organisms that are able to reproduce are included
in the taxonomic system. cellular organisms that cannot reproduce, such as viruses, are
not included. viruses, viroids, satellites, and prions are all organisms that lack certain
traits to be included in the three domain system. viruses and prions do not contain
certain cells, and they do not have an energy metabolism system. another factor that
separates them from the three domain system is that they do not contain cell organelles.
these are why viruses, viroid, satellites, and prions are not included in the three-domain
system.
why aren't viruses, viroids, satellites, and prions included in the tree domain system? (your
answer must give some level of detail to help explain your answer).
in the beginning, the term prokaryote was used to imply a close evolutionary
relationship between bacteria and archaea. the term prokaryote is no longer used in this
context because of the vast diversity between bacteria and archaeal. when the term
prokaryote was first used it was believed that prokaryotes lack a nucleus, which is not
the case since some bacteria contain a nucleus-like structure. this is why the term
, Page |3
prokaryote us considered an adequate descriptor of the organisms found in the archaeal
and bacterial domains.
why is the term prokaryote considered an inadequate descriptor by some microbiologists for
organisms found in the archaea and bacterial domains?
bacteria have peptidoglycan in cell walls and they have a single origin of replication.
archaea have multiple origins of replication and are composed of more than one type of
flagellin. eukaryotic cells have true membrane-bound nuclei and other organelles, have
DNA complexes with histones, have a nucleus, and contain a cytoskeleton. Three
structures that these domains all have in common are they contain membranes, DNA,
and ribosomes.
compare and contrast bacterial, archaeal, and eukaryotic cells. list three major differences
between them. then list three structures or properties they have in common.
four eukaryotic cells have membrane-bound organelles which include a membrane-
bound nucleus. bacteria and archaeal cells do not contain membrane-bound nuclei.
bacteria do have a nucleus-like structure that is not membrane-bound, whereas archaea
has no nucleus-like structure. this is the reason that the roles of the three different
domains' membranes are different.
the most obvious difference between eukaryotic bacteria and archaeal cells is in there use of
membranes. specifically, compare the roles of bacteria and archaeal plasma membrane with
those of the organelle membranes in eukaryotes.
fungi
Protists contain all of the following forms of life except
A. protozoa.
B. fungi.
C. slime molds.
D. algae.
eukaryotes
Cells with a relatively complex morphology that have a true membrane-delimited nucleus are
called
A. prokaryotes.
, Page |4
B. eukaryotes.
C. urkaryotes.
D. nokaryotes.
prokaryotes
Cells with a relatively simple cell morphology that do not have a true membrane-delimited
nucleus are called
A. prokaryotes.
B. eukaryotes.
C. urkaryotes.
D. nokaryotes.
woese
The ribosomal RNA studies that led to the division of prokaryotic organisms into the Bacteria
and the Archaea were begun by
A. Pasteur.
B. Woese.
C. Needham.
D. Watson.
cells lack response to external environment
Definition of life includes all of the following except
A. cells maintain internal order.
B. cells use energy and have a metabolism.
C. cells reproduce.
D. cells lack response to external environment.
both catalysts and structural elements
Proteins function in modern cells as
A. catalysts.
B. hereditary information.
C. structural elements.
D. both catalysts and structural elements.
protein
