Microbiology EXAM 1 chapters 1-7 Questions & Answers Already Passed!!
• What organisms are considered microorganisms and are the subjects of study in microbiology?
Microorganisms are Prokaryotes(bacteria & archaea) and eukaryotes(protozoa, algae, some fungi and helminths). Microbiology also i...
Microbiology EXAM 1 chapters 1-7 Questions & Answers
Already Passed!!
• What organisms are considered microorganisms and are the subjects of study
in microbiology?
Microorganisms are Prokaryotes(bacteria & archaea) and eukaryotes(protozoa, algae,
some fungi and helminths). Microbiology also includes studying viruses .
Which two are encompassed by the term prokaryotes?
bacteria and archaea
What are some examples of "small" things that are not covered by microbiology?
Are all prokaryotes microbes?
insects, macroscopic fungi, algae, and individual cells of macroscopic organisms. YES
all prokaryotes are microbes.
• Why are helminths (complex, multicellular animals) covered under
microbiology?
because their infective forms are MICROSCOPIC. cause infectious disease in
microscopic forms.
• What are general size ranges of eukaryotic microbes, Bacteria and Archaea, and
viruses?
Bacteria/archaea= 1-10 um
Eukaryotes= 10-100 um
viruses= 0.02-0.2 um
• Electron microscopy is generally required to visualize what type of microbe?
Which types can generally be visualized by light microscopy?
bacteria cells and viruses.Eukaryotes and bacteria can generally be visualized by light
microscopy
• Approximately how long have microbes been present on Earth? Which types of
microbes were first to appear?
3.5 billion years for prokaryotes(bacteria/archaea) and 1.8 billion years for eukaryotes
Approximately when did Cyanobacteria first appear, and what impact did their
evolution have on Earth's atmosphere?
2.5 million years ago. they are responsible for making oxygen in the environment
(aerobic respiration) and paved the way for extracellular life.
• What are some examples of ways in which humans make use of microbes and
their products or activities?
Biotechnology- when humans manipulate microorganisms to make products in an
industrial setting
Genetic engineering- manipulates genetics of microbes plants and animals for the
purpose of creating new produces
EX) cheese, bread, alcohol, yogurt, sauerkraut, kimchee, chemicals and antibiotics
• What is the human microbiome? How does the number of total microbial cells
present in the human microbiome compare to the total number of human cells in
the body?
the human microbiome is a set of microbes that are present on a typical human.
Microbes outnumber our own cells by >10 fold.
,• Do most microbes associated with humans (or plants) cause disease? Be able
to interpret Table 1.1 in the textbook regarding the comparison of the number of
deaths caused by microbes (infectious diseases) vs. other causes.
Most microbes cause no harm. 10 billion new infections cause every yr from microbes.
infectious disease are among the most common causes of death in the U.S. and world
wide.
• What were the contributions of the following prominent microbiologists?
Antonie van Leeuwenhoek, Louis Pasteur, Ferdinand Cohn, Joseph Lister, Robert
Koch, Alexander Flemming.
Leeuwenhoke- First person to see bacteria invented/advanced the microscope
Hook- first person to see microbes
Pasteur- Disproved spontaneous generation (swan necked flask experiment)
Cohn- Discovered heat resistant endospores and steralization
Lister- first person to introduce aseptic technique
Koch-Developed a series of postulates that verified pasteurs germ theory of disease
and established a link between microbes and the disease it caused
Flemming- discovered antibiotics in 1928
• What is the germ theory of disease? How did the ability to grow microorganisms
in pure culture contribute to the germ theory of disease?
germ theory of disease is showing that human diseases could arise from infection.
Koch's Postulates would provide absolute proof that a specific microorganism was the
cause of a particular disease:
1)The suspected causative microorganism must be present in every individual with the
disease.
2)The causative microorganism must be isolated and grown in pure culture.
3)The pure culture must cause the disease when inoculated into an experimental
animal.
4)The causative microorganism must be re-isolated from the experimental animal and
reidentified in pure culture.
• How is binomial nomenclature correctly used to write the name of a given
microbe? What do "generic" and "specific" names refer to?
- combination of the genus(capitalized) and species(lowercase)
-italicized when written in print
-underlined when written by hand
- genus name can be abbreviated to the first initial
• What are some important differences between Whittaker's 5 Kingdom tree of life
and the Woese-Fox 3 Domain tree of life? Which of these incorporates the
comparison of molecular characteristics such as DNA and protein sequences?
What are the three Domains of life?
-whittakeers 5 kingdom includesanimals, plantss, fungi, protists and monera. Based on
MORPHOLOGICAL or CHEMICAL characteristics.
-Whose-Fox system is based on analysis of gene (DNA). consists of 3
domains(bacteria, archaea and eukarya)
• What are four structures that all Bacteria possess? What are three structures
that most Bacteria possess? Which are present in only some Bacteria?
, ALL bacteria- Cytoplasm, cell membrane, ribosomes, chromosomes
MOST bacteria- cell wall, glycocalyx,cytoskeleton
SOME bacteria-Flagella, Phili, fimbriae, outer membrane, plasmids, inclusions, micro-
compartments, endospores, intracellular membrane.
• What two structures generally control the morphology of a bacterial cell? What
are some common morphologies of bacterial cells? What does pleomorphic
mean?
cell wall and cytoskeleton. Pleomorphic means that cells may very in shape and size
caused by variations in cell wall structure. Common morphologies are coccus, rods,
filaments, spirillum, vibro and spirochete.
• How does the general conservation of cell morphology and arrangement within
a given species or group of microbes aid microbiologists in the study of
microbes?
helps identify different types of bacteria.
• What is the major function of bacterial flagella? What energy source is used to
power flagellar rotation?
swimming motility. Powered by proton motive force which is in the cell membrane.
• What are four different types of flagellar arrangement on the cell?
Monotrichous(one flagellum), lophotrichous(small bunches), amphitrichous(two at each
poles), peritrichous( randomly dispersed over the surface of the cell)
• What is chemotaxis? What are some examples of other types of taxes (plural of
taxis)?
Chemotaxis is how bacteria move in response to chemical signals. ex. of other types
include phototaxis(response to light) and aerotaxis(response to oxygen)
• Which direction of flagellar rotation (CCW or CW) results in "running", and
which results in "tumbling"? How can the relative balance of running vs. tumbling
result in chemotaxis toward an attractant?
CW= tumbling, reverses. a change in orientation course.
CCW= running, forward movement.
-toward an attractant we want to increase the time CCW rotation in proportion to CW
when favorable conditions are sensed.
• How do the structure (i.e. number/cell and length) and functions of pili and
fimbriae compare? Which of these structures can be involved in twitching motility
and DNA exchange by conjugation?
Pili=longer than fimbriae(1-2um) few per cell. Involved in twitching motility and DNA
exchange by attachment.
fimbriae= short (0.1-0.2 um) many per cell.
• What are two major types of glycocalyx, and what is the major macromolecular
component of glycocalyx?
two types are a capsule and a slime layer. The major macromolecular component is
protein and polysaccharides.
What are some similarities and differences between capsules and slime layers?
Capsules are more tightly attached to the cell and
slime layers are more loosely attached to the cell and extend farther away. BOTH are
used for adhesion and biofilm formation and serve as a protective layer.
What role does glycocalyx play in biofilm formation?
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