Mastering Microbiology 13th edition – Chapter 6 Questions and Answers

Psychrophile Answer-An organism with a growth temperature optimum of 15 degrees Celsius or lower and a maximum growth temperature below 20 degrees Celsius. .Psychrotroph - Answer-An organism that grows slowly in the cold but has an optimum growth temperature of 25° C .Mesophile - Answer-An organism that grows between about 10°C and 50°C; a moderate-temperature-loving microbe. .Thermophile - Answer-An organism whose optimum growth temperature is between 50°C and 60°C; a heat loving microbe. .Hyperthermophile - Answer-An organism whose optimum growth temperature is at least 80°C; also called extreme thermophile. .Minimum growth temperature - Answer-The lowest temperature at which a species will grow .Optimum growth temperature - Answer-The temperature at which a species grows best .Maximum growth temperature - Answer-The highest temperature at which a species will grow .Psychrotroph - Answer-Organisms most likely to be encountered in low-temperature food spoilage because they grow fairly well at refrigerator temperatures .Acidophile - Answer-An organism that grows best at a pH of 4 or less .Plasmolysis - Answer-Loss of water from a cell in a hypertonic environment .Extreme halophiles - Answer-An organism that lives in a highly saline environment, such as the Great Salt Lake or the Dead Sea .Obligate halophile - Answer-An organism that requires high osmotic pressures such as high concentrations of NaCl .Facultative halophile - Answer-An organism capable of growth in, but not requiring, 1-2% salt .Nitrogen fixation - Answer-Process of converting nitrogen gas into nitrogen compounds that plants can absorb and use .Trace elements - Answer-A chemical element required in small amounts for growth