Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Antibiotic use in livestock wikipedia , lookup
Epidemiology wikipedia , lookup
Compartmental models in epidemiology wikipedia , lookup
Focal infection theory wikipedia , lookup
Eradication of infectious diseases wikipedia , lookup
Hygiene hypothesis wikipedia , lookup
Public health genomics wikipedia , lookup
Infection control wikipedia , lookup
Module Homework # 1 Section A, Question Numbers 1 – 7, and 10 – 12 1. What is Microbiology? - 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.” - 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? - 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. - 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. - 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. - 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. - 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. - 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. - 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? - 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. - The causative agent must be present in every one of the disease and cannot be present in healthy animals. - 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.) - The same disease must be reproduced in healthy animals that have been injected with organisms from the pure culture. - 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? - 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. - 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? - 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? - 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.