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BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS WITH ANSWERS latest update 2022
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BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONSWITH ANSWERS latest update 2022
Chapter 1:
1. Compare the scientists’ beliefs and experiments for spontaneous
generation.
Aristotle:
- proposed spontaneous generation: living things can arise from nonliving
matter.
Redi:
- When decaying meat was kept isolate from flies, maggots never
developed. Meat exposed to flies was soon infested. Scientist’s began
to doubt Aristotle’s theory.
Needham:
- Scientists didn’t believe that animals could arise spontaneously,
but that microbes could. Neeham’s experiments with beef gravy
and infusions of plant material reinforced this idea.
Spallanzi:
- Results contracted Needham’s findings. Concluded that: Needham
failed to heat vials sufficiently to kill all microbes or had not
sealed vials tightly enough.
Microorganisms exist in air and can contaminate experiments.
Spontaneous generation of microorganisms does not occur. The debate
continued until the experiments conducted by Louis Pasteur.
Pasteur:
- Performed investigations of spontaneous generation. When the “swan-
necked” flasks remained upright, no microbial growth appeared. When
the flask was tilted, dust from the bend in the neck seeped back into
the flask and made the infusion cloudy with microbes within a day.
2. What were the scientists/physicians Leeuwenhoek, Snow, and Lister known
for?
Leeuwenhoek:
- bacteria, protozoa, mycology (fungi), parasitology (protozoa and
animals), phycology (algae).
Snow: epidemiology
Lister: antiseptic medical techniques
3. What are the major groups of microorganisms, and are they prokaryotic,
eukaryotic, or acellular?
Bacteria and Archaea: prokaryotic (lack
nuclei) Fungi: eukaryotic (have membrane-
bound nucleus) Protozoa: single-celled
eukaryotes
Algae: unicellular or multicellular
4. Describe the steps in the scientific method.
Scientific method:
BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS
WITH ANSWERS latest update 2022
, BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS
WITH ANSWERS latest update 2022
- Observation leads to question
- Question generates hypothesis
- Hypothesis is tested through experiments
- Results prove or disprove hypothesis
5. Which scientist had steps to identify the etiological agent, and what are
those steps?
Robert Koch: studied disease causation (etiology)
Koch’s postulates:
- Suspected causative agent must be found in every case of
the disease and be absent from healthy hosts.
- Agent must be isolated and grown outside the host.
- When agent is introduced into a healthy, susceptible host, the host
must get the disease.
- Same agent must be found in the diseased experimental host.
Chapter 11
1. What are the main shapes of prokaryotes and
arrangements? Describe a coccobacillus.
Main shapes:
- Bacillus: rod shaped
- Coccus: spherical/round
- Coccobacillus: intermediate between cocci and bacilli. Very short
rods that can be mistaken for cocci
- Vibrio: curved rod shape
- Spirillum: curved/spiral
- Spirochete: corkscrew
- Pleomorphic: alter shape to environment
- Star
Arrangements: results from two aspects of division during binary fission.
- Planes in which cells divide.
- Separation of daughter cells.
2. What are the differences between bacteria and archaea? Where may
archaea live?
Bacteria: cells walls contain peptidoglycan; some lack cell walls.
Archaea: cell walls are composed of polymers other than peptidoglycan.
- Found everywhere there is sufficient moisture; some have been
isolated from extreme environments.
3. Why do bacteria form endospores, and which ones are medically relevant?
- Produced by Gram-positive bacteria Bacillus and Clostridium
- Primary function is to ensure the survival of the bacteria through
periods of environmental stress.
- Can create toxins that cause tetanus, anthrax, and gangrene.
- E. Coli cannot produce toxins.
BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS
WITH ANSWERS latest update 2022
, BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS
WITH ANSWERS latest update 2022
4. What are some medically relevant bacteria and the disease they cause?
Clostridia: produce toxins that cause diseases in humans.
Bacillus thuringiensis: toxin is used by farmers and gardeners as an
insecticide.
Bacillus anthracis: causes anthrax.
Listeria: contaminates milk and meat products.
Streptococcus and Enterococcus: cause numerous diseases, produces toxins
and enzymes that contribute to disease.
Chlamydia: STD – most common in the US
Borrelia: lyme disease
5. How does binary fission differ from endospore formation?
Binary fission: asexual reproduction. Most common form of
reproduction in prokaryotes such as bacteria. Occurs in some
single-celled eukaryotes.
Chapter 3
1. How do prokaryotes differ from eukaryotes in terms of cellular structure?
What is the size difference?
Prokaryotes:
- Contains no nucleus - has DNA in nucleoid.
- 70S ribosomes: 50S and 30S.
- Haploid.
- Single celled.
Eukaryotes:
- Contains nucleus.
- Internal structures and organelles.
- Single celled or multicellular.
- 80S ribosomes: 60S and 40S
2. What are the differences in the cellular envelope of a gram + and
gram – bacterium? What is the periplasmic space?
Gram-positive: thick layer of peptidoglycan, purple when stained,
susceptible to antibiotics
Gram-negative: thin layer of peptidoglycan, bilayer membrane outside and
contain phospholipids, proteins, and lipopolysaccharide (lipid A), pink when
stained, resistant to antibiotics
3. What are the effects on a cell when they are placed in a hypertonic,
hypotonic, or isotonic solution?
Hypertonic: shrink-crenation
Hypotonic: burst
Isotonic: stay the same
4. How is the cell membrane selectively permeable? How does this layer
differ from the cell wall in bacteria?
- The cell wall controls passage of substances into and out of the cell
(active and passive transport). It is made up of proteins and
BIOS242 MICROBIOLOGY FINAL EXAM QUESTIONS
WITH ANSWERS latest update 2022
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