Microbiology Lab Exam 2- Biol 2120. Questions and answers. Graded A+..

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What is the purpose of the Eukaryotic Microbes: Protozoa and Helminthes laboratory exercise? - Ans-1. To recognize adult forms, cysts, or the trophozoite stage of parasitic protozoa. 2. To recognize ... adult and egg of a common helminth. 3. To understand the life cycle of the malaria parasite and the challenge of producing a malaria vaccine. List five (6) protozoal diseases and their causative agents? - Ans-1. Ameobas- Entamoeba histolytica. 2. Giardias- Giadia lamblia. 3. African sleeping sickness- Trypanosomiasis. 4. Leishamniasis- Leishmania. 5. Malaria- Plasmodium. 6.Babesiosis- Babesia Give the genus and species name of two medically important helminthes and the diseases they cause. Describe where and how they cause infection in the human body. - Ans-1.Taenia saginata: inhabit small intestine of digestive tract caused by ingesting contaminated food/water. 2.Trichinella spiralis: infected by eating improperly cooked meat that contains infected juvenile worms. Juveniles are digested from muscle & penetrate into tissues of small intestine. How many cases of malaria were reposted for all W.H.O. reporting regions? - Ans-212 million The Genus and species of the most deadly form of malaria is _______ _________ - Ans-Plasmodium faciliparum Malaria is said to be endemic to ___________ ___________ - Ans-Sub-Saharan Africa & India The definitive host of malaria is _________ - Ans-mosquitos Which global region has the highest number of schistosomiasis cases? - Ans-Africa What is the purpose of the Control of Microbial Populations: Effects of Heat experiment? - Ans-1. Determine the heat sensitivity of bacteria. 2. To understand the effect of heat on microbial populations. Thermal Death time for: 1. Bacillus subtilis at 100 degrees Celcius. 2. Staphylococcus aureus at 100 degrees Celcius. - Ans-1. greater than 40 minutes 2. 2 minutes Define thermal death time. - Ans-The shortest period of time required to kill all the microbes in a sample, when exposed to a specific temperature under standard conditions. Compare the mechanisms of microbial death by dry and moist heat. - Ans-1. .Moist heat is more effective than dry heat, killing the microbes faster and at lower temperatures. 2. Moist heat causes denaturation of certain viral proteins, whereas dry heat causes oxidation of organic constituents. What was the purpose of including the controls in this experiment? - Ans-To establish a baseline to compare the results of the main experiment. Control group rules out environmental variables. Give the factors that would affect the thermal death time of bacterium. - Ans-1. Bacterial spores are heat resistant. 2. The past history of the culture. 3. The organic matter present. 4. The amount of water present. Pasteurization - Ans-Process in which fluids are heated at temps below boiling point to kill pathogenic microorganisms in the vegetative state without altering the fluids palatabiity. Autoclaving - Ans-Preferred method of sterilization in hospitals. Pressurized device designed to heat aqueous solutions above their boiling point (121 degrees C) at normal atmospheric pressure to achieve sterilization. Tyndalization - Ans-Process of repeating & alternating cooling and boiling of the medium will include spores to germinate into heat sensitive vegetative cells. Over 3 consecutive days will sterilize the medium from the spores. What was the purpose of the Control of Microbial Populations: Effect of Chemicals lab exercise? - Ans-1. To distinguish betweem antiseptic and disinfectantant, microbicidal and microbistatic. 2. To recognize the advantages/disadvantages of using various types of chemical anti-microbial agents. 3. To evaluate the relative effectiveness of various anti-microbial chemicals Name the chemicals that inhibited both the bacteria tested. - Ans-Lysol Name the chemical that did not inhibit any of the bacteria. - Ans-Ethanol Antiseptics - Ans-Substances applied to body surfaces, especially skin that kill or inhibit growth of microorganisms. Disinfectants - Ans-Substances applied to nonliving surfaces that kill or inhibit growth of microorganisms. Microbicidal - Ans-Killing of microorganisms Microbistatic - Ans-Inhibit the growth of microorganisms Are the terms antiseptic and disinfectant interchangeable? - Ans-Antiseptics and disinfectants are terms that are used interchangeably, however the differences between the two are quite numerous. Is this procedure quantitative or qualitative in nature? Explain. - Ans-Qualitative: when a filter paper disc is soaked in disinfectant/antiseptic and placed on a bacterial lawn, the chemical diffuses into the agar. If the microbe is sensitive a clear zone of inhibition develops. If the microbe is resistant, bacteria will grow around the disc. Name a standard test for the effectiveness of a disinfectant. Which chemical agent is used as a standard and what are the standard test organisms? - Ans-1. Tube dilation method; Disc diffusion method 2. Phenol is used as the standard chemical agent. 3. Rapid growing bacteria. What is the purpose of the Carbohydrate Fermentation by bacteria lab exercise? *** - Ans-1. To understand the physiological role of carbohydrate fermentation by bacteria. 2. To interpret carbohydrate fermentation test. What is the role of fermentation in bacteria? *** - Ans-1. Provides energy (ATP) for bacteria and yields other end products such as acid and alcohols. 2. Fermentation does not require oxygen. List three organic molecules that are produced by catabolizing/fermenting bacteria. *** - Ans-1. citric acid 2. lactic acid 3. acetic acid. List three gases that are produced by catabolizing/fermenting bacteria. *** - Ans-1. Hydrogen 2. Carbon Dioxide 3. Hydrogen Sulfide. [Show More]

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