MIC 205 Exam 3 Questions with All Correct Answers

MIC 205 Exam 3 Questions with All Correct Answers Psychrophiles - Answer-cold-loving microbes Mesophiles - Answer-those growing best between 20 degrees and 40 degrees celcius; the human pathogens are in this group Thermophiles - Answer-heat loving microbes minimum growth temperature - Answer-the lowest temperature at which the species will grow optimum growth temperature - Answer-the temperature at which the species grows best maximum growth temperature - Answer-the highest temperature at which growth is possible Psychrotrophs - Answer-Grow between 0°C and 20-30°C Cause food spoilage Hyperthermophiles - Answer-Organisms that grow in extremely high temperatures (90 degrees C) Extremethermophiles - Answer-thrive in very hot environments. optimum growth rate is at 80 degree C Acidophiles - Answer-grow in acidic environments Plasmolysis - Answer-This happens when a cell shrinks inside its cell wall while the cell wall remains intact. extreme halophiles - Answer-live in highly saline environments obligate halophiles - Answer-those that grow in up to 30% salt, require high osmotic pressure facultative halophiles - Answer-those that do not require, but can tolerate high salt concentrations, but can grow at salt concentrations of 2%. nitrogen fixation - Answer-Process of converting nitrogen gas into ammonia trace elements - Answer-required by an organism in only minute quantities obligate anaerobes - AnswerObligate aerobes require - Answer-Oxygen facultative anaerobes - Answer-can live with or without oxygen superoxide radicals - Answer-a toxic anion with an unpaired electron superoxide anion - Answer-A toxic anion with an unpaired electron. superoxide dismutase - Answer-an enzyme that destroys superoxide peroxide anion (O2 2-) - Answer-toxic form of oxygen found in hydrogen peroxide Catalase - Answer-An enzyme that breaks down hydrogen peroxide. colony of bacteria - Answer-A visible mass of microbial cells arising from one cell or from a group of the same microbes. peroxidase - Answer-an enzyme that destroys hydrogen peroxide Hydroxyl radical (OH) - Answer-A toxic form of oxygen formed in cytoplasm by ionizing radiation and aerobic respiration. aerotolerant anaerobes - Answer-an organism that does not use molecular oxygen but is not affected by its presence Microaerophiles - Answer-An organism that grows best in an environment with less molecular oxygen than is normally found in air. organic growth factors - Answer-An essential compound that an organism is unable to synthesize. quorum sensing - Answer-The ability of bacteria to sense the presence of other bacteria via secreted chemical signals. culture medium - Answer-The nutrient material prepared for growth of microorganisms. Inoculum - Answer-Microbes introduced into a culture medium to initiate growth. Culture - Answer-The microbes that grow and multiply in or on a culture medium. Agar - Answer-a gel-like polysaccharide compound used for culturing microbes; extracted from certain red algae Chemical defined medium - Answer--exact chemical composition is known -usually used for growth of bacteria for laboratory experiments or autotrophic bacteria nutrient broth - Answer-liquid medium containing beef extract and peptone Complex medium - Answer-A culture medium that contains protein digests, extracts, or other ingredients that vary in their chemical composition Nutrient agar - Answer-Nutrient broth containing agar. Reducing media - Answer-contain ingredients that chemically combine with O2 and are heated to kill off O2, growth of obligate anaerobes Capnophiles - Answer-Microbes that require high low oxygen and high CO2 conditions selective media - Answer-suppress unwanted microbes and encourage desired microbes enrichment culture - Answer-A culture medium used for preliminary isolation that favors the growth of a particular microorganism BSL-1 - Answer-no special precautions; basic teaching labs