Microbiology (MICRO 307) Past Paper PDF

Microbiology (MICRO 307) Topics to be covered: Historical overview of Microbiology. Structure of microbial cell and function. Microbial Metabolism. Microbial Growth. Microbial diversity. Microorganisms and their Applications in Biotechnology....

Microbiology (MICRO 307) Topics to be covered: Historical overview of Microbiology. Structure of microbial cell and function. Microbial Metabolism. Microbial Growth. Microbial diversity. Microorganisms and their Applications in Biotechnology. MICRO ۳۰۷ Textbooks: - Essential microbiology Available at: http://www.grsmu.by/files/file/university/cafedry/microbiologii-virysologii- immynologii/files/essential_microbiology.pdf crobiolgy%20(Wiley,%202005).pdf MICRO ۳۰۷  Percentage of Total No Assessment task Week Due Assessment Score 1. Mid Exam ۹-۸ 15% 2. Quiz (written test) 5% 3. Infographic (Rubric) ۱۰ 7% 4. Class participation All weeks 3% Labs reports and Continues lab All weeks 30% 5. evaluation 6. Final Exam ۱۷ 40%... 100% MICRO ۳۰۷  Lecture 1 Historical overview MICRO ۳۰۷ Objectives: Memorize the historical overview of Microbiology Distinguish microorganisms and how they are classified. Recognize microbial Taxonomy. Cite why microbiology is important.  What is Microbiology?  Microbiology is the science that study, living organisms that are so small to be seen with the naked eye.  Thus, these organisms are called microbes or microorganisms (M.Os).  Includes bacteria, fungi (yeasts and molds), viruses, Microalgae, and protozoa. Viruses, are the smallest and are non-cellular entities sometimes regarded as link between life and nonlife.  Why is Microbiology important? – It may surprise you to learn that the vast majority of M.Os are beneficial, and without them, life on our planet could not continue. For example: 1. M.Os form the basis of food chain: a) Certain M.Os perform photosynthesis, thus generating food and oxygen that are critical to life on Earth. b) Incorporate nitrogen gas from the air into organic compounds, thereby recycling organic matter. c) Break down plant and animal wastes. d) Microbes in animal intestines help digestion and the synthesis of some vitamins (B and K). 2. Most M.Os have commercial applications. a) Synthesis of organic acids, and alcohols.  During World War I, the production of acetone by microorganisms was discovered and used for making cordite (a smokeless form of gunpowder) and played a significant role in determining the outcome of the war. b) Used in the food industry in producing vitamins, vinegar, pickles, alcoholic beverages, cheese, yogurt and bread. c) Produce enzymes used as digestive aids, drain cleaner and even helped produce your jeans. d) Produce therapeutic substances such as insulin.  On the other hand only a minority of microorganisms are pathogenic (disease- producing). How do we know Microbiology from the perspective of the ‘golden age’ and beyond ?  Before the invention of the microscope, microbes were unknown to scientists. Thousands of people died in devastating epidemics, the causes of which were not understood. Entire families died because vaccinations and antibiotics were not available to fight infections.  We can get an idea of how our current concepts of microbiology developed by looking at a few historical milestones in microbiology that have changed our lives.  First, however, we will look at the major groups of microbes and how they are named and classified.  Naming of Microorganisms The system of nomenclature (naming) for organisms we use today was established in 1735 by Linnaeus. Assign each organism two latinized names-the genus is the first name and is always capitalized; then species name follows and is not capitalized. Both names are italics. After a scientific name has been mentioned once, it can be abbreviated with the initial of the genus followed by the species. Examples: Staphylococcus aureus / Staphylococcus aureus -Staph. aureus Escherichia coli – E. coli Two latinized names Genus Species First name Sconed name capitalized Not capitalized Escherichia coli Staphylococcus aureus Both names are italics  Scientific names may: 1- describe an organism. 2- honor a researcher. 3- identify the habitat of a species. For example, consider Staphylococcus aureus. Staphylo- describes the clustered arrangement of the cells; coccus indicates that they are shaped like spheres. The species, aureus indicates golden colonies.  The genus of Escher ichia coli is named for a scientist Escherich, whereas the species, coli, reminds us that E. coli live in the colon, or large intestine.  Table 1.1 contains more examples.  Types of Microorganisms 1. Bacteria o Unicellular and the genetic material is not enclosed in a nuclear membrane thus they are prokaryotes. o The cell walls composed of a carbohydrate and protein called peptidoglycan. o Shapes: Bacillus (rod-like), coccus (spherical) and spiral (curved). o Groupings: singles, pairs, chains, or other. o Reproduction by dividing into two equal cells by binary fission. o Nutrition: a- Most bacteria utilized organic matter from dead (saprophytes) or living organisms (parasites). b- Some share benefits with other organisms (mutualistic). c- Some bacteria can manufacture their own food by photosynthesis (photosynthetic).  2. Archaea  Prokaryotes like bacteria, but their cell walls lack peptidoglycan. Found in extreme environments and divided into: 1. The methanogens, produce methane. 2. The extreme halophiles, live in extremely salty environments. 3. The extreme thermophiles live in extremely hot environments.  3. Fungi  Eukaryotes, whose nucleus surrounded by nuclear membrane.  Cell walls composed of chitin.  Unicellular or multicellular. 1. Few fungi are unicellular called yeasts. Are oval microorganisms larger than bacteria. 2. Most fungi are multicellular called molds. Form visible masses called mycelia, which are composed of long filaments (hyphae) that branch. 3. The cottony growths found on bread and fruit are mold mycelia.  4. Protozoa  Unicellular eukaryotic microbes.  They move by pseudopods (false feet) e.g amoeba.  Other protozoa move by long filaments called flagella or shorter called cilia.  Live as saprophytes or parasites. 5. Algae  Abundant in water.  Photosynthetic eukaryotes need light, water, and carbon dioxide for growth.  Cell wall composed of cellulose.  6. Viruses  They are the smallest microbes (seen only with electron microscope).  Are acellular (not cellular).  Structurally very simple i.e contains only one type of nucleic acid, either DNA or RNA surrounded by a protein coat.  Sometimes the coat is surrounded by an additional lipid layer called an envelope.  No metabolism, respiration, growth in size, but it can multiplied.  Reproduce only by using the cellular machinery of their hosts.  Thus, viruses considered to be living only within host cells.  On the other hand, viruses are not considered to be living because outside living hosts, they are inert. Thus, regarded as link between life and nonlife.  Classification of Microorganisms  Before the discovery of microbes, all organisms were grouped under;  Animal kingdom or Plant kingdom.  When microorganisms discovered in the 17th century, a new system of classification was introduced.  Woese (in 1978), devised a system of classification based on the cellular organization of organisms. He grouped all organisms in three domains: 1) Bacteria (cell walls contain a protein-carbohydrate complex called peptidoglycan). 2) Archaea (cell walls lack peptidoglycan). 3) Eukarya: a) Animals (invertebrates and vertebrates). b) Plants (flowering and nonflowering plants). c) Protists (algae and protozoa). d) Fungi (yeasts, and molds).  Viruses not classified under any group as they are acellular.  Brief History of Microbiology I-The First Observations Discovery of microscope (Hooke – Van Leeuwenhoek) II-The Debate over Spontaneous Generation Redi proved that maggots did not arise spontaneously his respond to other scientists Needham claimed that microbes developed spontaneously from the fluids. Pasteur proved that microbes in the air were the agents responsible for contaminating. He respond to other scientists. established the basis of sterilization. III- The golden Age of Microbiology IV- Fermentation and Pasteurization V- The Germ Theory of Disease: Koch's postulates VI- Vaccination Jenner VII- The Birth of Modern Chemotherapy Fleming IIX- The birth of recombinant DNA Technology Brief History of Microbiology  Microbiology dates back only 200 years, while the recent discovery of Mycobacterium tuberculosis DNA in 3000-year-old Egyptian mummies proves that microorganisms were around us long ago but people didn’t know. I-The First Observations  In 1665 Hooke developed the first microscope and examined a thin slice of cork.  He observed the smallest structural units of cork and called it "little boxes" or "cells".  This was the beginning of the cell theory (that “all living organisms are composed of cells”).  Hooke's microscope was capable of showing large cells only, but lacked the resolution to see microbes.  Van Leeuwenhoek was the first to observe microorganisms with his microscope. He called them "animalcules".  He made detailed drawings of them in rainwater, and in his teeth(Figure).  II-The Debate over Spontaneous Generation  After Van Leeuwenhoek discovery of microorganisms, the scientific community at that time became interested in their origins.  Many scientists and philosophers had believed that some forms of life could arise by spontaneous generation from non-living objects. 1. Toads, snakes, and mice could be born of moist soil. 2. Flies could emerge from manure. 3. Maggots, the larvae of flies, could arise from decaying corpses.  Redi (in 1668) proved that, maggots did not arise spontaneously from decaying meat.  He filled two jars with decaying meat. The first was left unsealed; the flies laid their eggs on the meat, and the eggs developed into larvae.  The second jar was sealed, the flies could not lay their eggs on the meat, no maggots appeared.  Redi's antagonists claimed that fresh air was needed for spontaneous generation. So Redi set up a second experiment, in which he covered the third jar with fine net so air can move freely. No larvae appeared in the jar.  Redi (in 1668) proved that, maggots did not arise spontaneously from decaying meat. The claim of spontaneous generation of microorganisms reemerged again (in 1745), when Needham found that, when heating chicken broth then pouring into covered flasks, they become turbid due to presence of microorganisms. Needham claimed that microbes developed spontaneously from the fluids. Pasteur filled several short-necked flasks with beef broth and then boiled. Some were closed while, others were left opened. In a few days, the opened flasks were found to be contaminated with microbes. The closed flasks, were free of microorganisms.  From these results, Pasteur proved that microbes in the air were the agents responsible for contaminating the broths in Needham's flasks.  Pasteur antagonists claimed that air is essential for spontaneous generation.  He responded by placing broth in open-ended, long-necked flasks and bent the necks into S-shaped curves (Figure).  The flasks were then boiled. The broth in the flasks did not show signs of microorganisms, even after months.  Pasteur's unique design allowed air to pass into the flask, but the curved neck trapped any airborne microorganisms that might contaminate the broth.  Furthermore, Pasteur showed that microorganisms can be destroyed by heat thus, established the basis of sterilization, which are now used in medicine and food industry. Figure: The defeat of spontaneous generation: Pasteur’s swan-necked flask experiment. In (c) the liquid putrefies because microorganisms enter with the dust. The bend in the flask allowed air to enter (a key objection of Pasteur’s sealed flasks) but prevented microorganisms from entering. Thanks For listening MICRO ۳۰۷