Download Module Homework # 1 Section A, Question Numbers 1 – 7, and 10

Module Homework # 1
Section A, Question Numbers 1 – 7, and 10 – 12
1. What is Microbiology?
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Microbiology is a branch of biology, which is the study of living things, that deals
with simple life forms, usually single celled, that cannot be seen with the naked eye.
2. Discuss Anton van Leeuwenhoek’s role in the development of microbiology and why he
is called the “Father of Microbiology.”
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Anton van Leeuwenhoek was a Dutch merchant who had no formal scientific
knowledge but had a wide base of knowledge and understanding of the art of lens
grinding and optics. He went on to study a wide and diverse assortment of materials.
These materials include blood, suspensions of feces and pepper water, semen, urine,
and water from gutters, lakes, rivers, wells, and the sea. Van Leeuwenhoek had over
400 microscopes that had maximum magnifications of over 300. He was able to
produce these microscopes by grinding a single lens. With these new microscopes, he
was able to see tiny living organisms which he called “animalcules” in a series of
letters that he wrote to the Royal Society of London over a span of 50 years. He
recorded his observations with painstaking accuracy and objectivity in these letters. In
a letter dated 1683 and another in 1692, he illustrated diagrams that clearly showed
the three major shapes of bacteria, namely bacilli (rod shaped), cocci (spherical
shaped), and spiral shaped bacteria. He is known as the Father of Microbiology for
these discoveries.” He did not pass on his technique of making telescopes to his
children or to an apprentice. He had over 400 telescopes when he died but only a few
remain and the rest have disappeared mysteriously.
3. What is the theory of spontaneous generation? What is another term for it?
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Another term for spontaneous generation is abiogenesis. The theory of spontaneous
generation is states that life can suddenly or spontaneously arise from decomposing
nonliving matter.
4. Briefly explain how Redi and Spallanzani tired to disprove the theory of spontaneous
generation.
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Francesco Redi, and Italian biologist, physician, and poet did not agree the theory of
spontaneous generation. He tried to disprove it by conducting a simple, yet classic
experiment. He set up 3 jars of decaying meat, one covered with gauze, the second
with parchment paper, and the third left uncovered. Flies were attracted to the first the
first two jars but could not land on the meat. Flies did land on the meat in the third
uncovered jar, and eventually maggots developed. However, the other two jars did
not give rise to maggots. Redi concluded that decaying meat does not give rise to
maggots. Flies must land on the decaying meat and deposit their eggs. Later these
eggs hatch and give birth to maggots.
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Lazzaro Spallanzani also did not agree with the theory of spontaneous generation and
conducted experiments to dispute the theory. During one of such experiments, he
boiled meat broth in a flask and then sealed the neck of the flask by melting its glass
neck. Thus, no microbes were allowed to enter and develop. However, if the neck was
broken, the broth eventually became turbid or cloudy with the growth of
“animalcules,” or microbes carried by contaminated air into the broth.
5. Discuss why Louis Pasteur and John Tyndall were finally successful at disproving the
theory of spontaneous generation.
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Louis Pasteur and John Tyndall were successful in disproving the theory of
spontaneous generation through the use of simple, clever experiments. In one series
of experiments conducted by Pasteur, he put beef broth into a long – necked flask. He
then melted the neck and drew it out into an S shape, creating a swan – necked flask.
After that, he boiled the flask. As the flask was being boiled, vapourization pushed
the air out of the flask through the opening at the end of the swan neck. The flask was
cooled and, following that, air was pulled back into it. As the air entered, it passed
over water condensation in the neck. The moisture droplets and the bend of the swan
neck managed to trap any airborne microorganisms and dust particles, thus keeping
the broth sterile. Air, or the “vital particle,” was still able to reach the broth, but the
broth remained clear. If the flask was tilted, and the broth touched the bend of the
neck and then ran back into the flask, the broth later became turbid. In a second round
of experiments, Pasteur used cotton as plugs for his sterilized broth – laden flasks.
The cotton plugs acted like filters, trapping the airborne microbes and dust particles.
He then, microscopically, examined these trapped microorganisms and found them to
be similar to the ones found in many intrusions. Therefore, if a cotton plug was
dropped into a sterile flask, the broth would soon be turbid. As a result of these two
experiments, Pasteur showed that life comes from life and is self producing, rather
than spontaneous. Thus the theory of biogenesis, that life comes from preexisting life,
overthrew the theory of abiogenesis.
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Some scientists tried to replicate Pasteur's experiments but were unsuccessful because
different laboratories came up with different results. So finally, in 1876, John
Tyndall, an English physicist, performed a series of experiments to point out the
inconsistencies between the various laboratories. In duplicating Pasteur's
experiments, he discovered that there were two different types of bacteria: the heat –
sensitive or labile form (vegetative cell) easily destroyed by boiling, and the heat –
resistant type called an endospore. He developed a technique to kill all heat
resistant endospores. Tyndall boiled a hay infusion for 1 minute. Afterward, upon
cooling, the endospores would germinate into heat labile vegetative cells. Then he
boiled the hay infusion again. The alternate process of heating and cooling was
repeated five separate times to kill all the endospores. This technique is now called
the fractional sterilization process or Tyndallization.
6. Explain how pasteurization prevents beer, wine, and milk from spoiling.
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Louis Pasteur developed the germ theory of fermentation – that is, the idea that
microorganisms are responsible for the fermentation of sugars – while examining
reasons for the excessive spoilage of beer and wine in the brewery industry. During
the process of fermentation, yeast will ferment the sugar in grapes to produce ethyl
alcohol. If a bacterium such as Acetobacter happens to contaminate the beer or wine
cask, the alcohol is changed to acetic acid (vinegar). This contamination alters the
taste and ruins the beer or wine. Pasteur devised a method to destroy the
contaminating bacteria in beer and wine by heating them to between 50*C to 60*C
(122*F to 140*F). This technique, called pasteurization, has been adapted for the
diary industry to destroy lactic acid forming bacteria which causes milk to go sour.
Milk is heated to 63*C (145.4*F) for 30 minutes, or to 72*C (161.6*F) for 15
seconds.
7. State and explain the germ theory of disease.
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Pasteur developed the germ theory of disease from the germ theory of fermentation.
The germ theory of disease states that specific microorganisms called bacteria are the
cause of specific diseases in both humans and animals. Pasteur developed specific
vaccines against anthrax in sheep, chicken pox, cholera, and rabies. These vaccines
were made from a weakened or attenuated pathogen (disease causing agent). Upon
injection into animals or humans, it would not cause the disease to develop but would
cause them to become immune to the disease. When Pasteur isolated the rabies virus
from the brain and spinal cord of a rabid dog, he weakened the virus by transferring it
from rabbit to rabbit. Using this attenuated virus, he perfected a method of
vaccination against rabies called the Pasteur treatment.
8. What is the difference between antiseptic surgery and aseptic surgery?
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Antiseptic surgery is the process of surgery whereby antiseptic, a chemical
compound, is spread upon incisions and equipment to inhibit or stop the growth of
bacteria without necessarily killing them while aseptic surgery is a process designed
to exclude the presence of all infectious pathogens.
9. List all the important points in Koch’s postulates.
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The causative agent must be present in every one of the disease and cannot be present
in healthy animals.
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The pathogen must be isolated from the diseased host and then grown in pure culture.
(In a pure culture only one type of bacterium is present.)
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The same disease must be reproduced in healthy animals that have been injected with
organisms from the pure culture.
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The same pathogen must then be recovered from the artificially infected animals and
that same pathogen reisolated in pure culture.
10. What contribution did Sir Alexander Fleming make to the conquest of disease?
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Sir Alexander Fleming discovered penicillin from the green mold (fungus)
Penicillium notatum in 1928. This would open the door to the discovery of many
antibiotics from different fungi. Penicillin, along with many of its derivatives, is still
one of the most widely prescribed antibiotics.
11. You are acting as an advisor to college student interested in the field of Microbiology.
Develop a list of possible career options based on the information gained in the first
chapter of the textbook.
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There are many career options in the field of microbiology some of which are:
a. Aquatic Microbiology: This area studies the microorganisms found in marine
(seawater) and fresh water. Human beings are becoming increasingly
dependent upon the sea for many of its products in the areas of nutrition,
health, and industry.
b. Agricultural Microbiology: This includes dairy and food microbiology. A
dairy microbiologist is concerned with the proper pasteurization, processing,
and grading of milk and milk products. These processes ensure that the dairy
product is safe for human consumption and is free from contamination and
spoilage.
c. Environmental microbiology: This area includes air, soil, sewage, and water
microbiology. In air microbiology, air is monitored to see what kinds and
numbers of microorganisms are present and how they are carried through the
air. The monitoring is important because many diseases can be caused by
airborne microbes that cling to dust and water droplets. Soil microbiology
studies the types and numbers of microorganisms found in the soil. This field
of study is essential because microbes are responsible for soil fertility, plant
maintenance, and recycling of dead organic matter (dead animals and plants)
into organic elements. Water and sewage microbiology is concerned with the
control of disease causing microbes found in drinking water and sewage, and
is achieved through a process of mechanical filtration and chemical treatment
of water. Sewage treatment involves the elimination of disease – causing and
odor – causing microorganisms. Thus, water and sewage microbiology is
essential to the health of humans as well as fish and other aquatic life.
d. Industrial Microbiology: There are countless products in daily use that are
produced by the chemical action of microbes. These include alcohol, beer,
wine, antibiotics, enzymes, organic acids, medicines, and vitamins. Industrial
microbiologists “exploit” these little microbes to produce essential products at
maximum volume with maximum cost.
e. Space Microbiology of Exobiology: Exobiology is a developing field of
microbiology that began when earth scientists launched the first space
satellite. A space microbiologist investigates the possibility of microbial life
in outer space and on other planetary bodies (extraterrestrial life). Exobiology
also deals with the prevention of contamination of earth microbes in outer
space and on other planets through our astronauts and spacecrafts and vice
versa.
f. Medical Microbiology: Medical microbiology is the study of bacteria, viruses,
fungi, parasites, and other microorganisms that may cause disease (pathogens)
or be infectious to humans or animals. Microorganisms are examined for their
growth characteristics, similarities and differences, reaction to antibiotics,
epidemiology, and biochemical reactions.
g. Veterinary Medicine: This studies the transmission and spread and control of
diseases between animals and from animals and humans. It also studies the
care and breeding of livestock for human nutrition and care of pets.
12. You are working as an assistant to Edward Jenner the scientist who thinks he has
developed a vaccine to prevent the disease Smallpox. You are trying to calm the fears of
the young boy who Dr. Jenner wants to test the vaccine on. What would you tell the
young boy?
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I would tell the young boy that if he takes the vaccine, his family would be free from
the disease and that he would be helping the society by making sure that no one gets
the disease anymore.
13. You have just been hired as a Nursing Assistant at a local nursing home. During
orientation they are stressing the importance of hand washing. This brings to mind
important information concerning which scientist you read about in this chapter?
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Hand washing in hospitals brings into mind Ignaz Philipp Semmelweis. He was the
one to establish the first real safety precaution in the hospital: all hands had to be
carefully cleansed before a patient was examined, and rooms were to be kept
scrupulously clean. He came up with this by noting that the death rates of patients
being visited by physicians and medical students who had come directly from the
morgue or autopsy room were much higher. After establishing the safety precaution,
the mortality rates on his wards dropped dramatically.