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Ch 6 Microbial Grow
Ch 6: Microbial Nutrition and Growth
Term | Definition |
---|---|
Acidophile | This organism likes a low pH. |
Superoxide dismutase | SOD |
Aerotolerantanaerobes | An organism that does not use molecular oxygen, but is not affected by it |
Agar | A complex polysaccharide used as a solidifying agent in culture media |
Alkalinophiles | These organisms live in alkaline soils and water up to pH 11.5 |
Anaerobes | These organisms cannot use molecular oxygen |
Barophiles | Organisms that live under extreme pressure |
Binary Fission | The means of bacterial reproduction |
Biofilms | Complex associations of large numbers of microorganisms, which are often different species that together attach to surfaces |
Catalase | An enzyme that degrades hydrogen peroxide to release water and oxygen |
Chemoautotrophs | These organisms use use carbon dioxide as a carbon source but obtain energy from redox reactions involving organic or inorganic molecules |
Chemoheterotrophs | These organisms use organic compounds for both energy and carbon. |
Colony | A visible mass of bacterial cells arising from one cell |
Complex | The exact chemical composition of this media varies from batch to batch and used for most heterotrophic bacteria |
Culture | Microbes that grow and multiply in or on a culture medium |
Death phase | The period of logarithmic decrease in a bacterial population |
Defined Medium | The exact chemical composition of this medium is known |
Differential Media | A solid culture medium that makes it easier to distinguish colonies of the desired organism |
Exponential Growth | The phase of the bacterial growth curve where generation time is constant |
Extreme thermophiles | Members of the Archaea that have an optimum growth temperature of 80C or higher |
Generation time | The time required for a population to double in number |
growth curve | A graph that plots the number of bacteria growing in a population over time |
growth factors | Small amounts of certain organic chemicals that they cannot synthesize |
Halophiles | Salt loving bacteria |
Hydroxyl radicals | Molecules resulting from ionizing radiation and from the incomplete reduction of hydrogen peroxide |
Lag phase | The time interval in a bacterial growth curve when there is no growth |
lithotrophs | These organisms acquire electrons from inorganic sources |
Log phase | Exponential growth |
Lyophilization | Freeze drying |
Mesophiles | These bacteria grow best between about 10C and 50C |
Nutrient | Any chemical required for growth of microbial populations |
Obligate aerobes | These microbes require oxygen as the final electron acceptor of the electron transport chain |
Obligate anaerobe | This type of anaerobe is killed in the presence of oxygen |
Optimum growth temperature | The temperature at which a species grows best |
organotrophs | These organisms acquire electrons from organic sources |
Peroxidase | An enzyme that breaks down hydrogen peroxide to water. |
Peroxide anion | A component of hydrogen peroxide, which is formed during reactions catalyzed by superoxide dismutase |
Photoautotrophs | These organisms use carbon dioxide as a carbon source and use light as an energy source |
Photoheterotrophs | These organisms acquire energy from light and acquire nutrients via catabolism of organic compounds. |
Plasmolysis | Loss of water from a cell in a hypertonic environment |
Psychro | The prefix that means cold |
quorum sensing | A process in which bacteria respond to the density of nearby bacteria |
Selective | Media that is designed to suppress the growth of unwanted bacteria and encourage the growth of desired microbes |
Singlet | Normal molecular oxygen that has been boosted into a higher energy state and is extremely reactive |
Stationary phase | The period in a bacterial growth curve when the number of cells dividing equals the number dying |
sterile | Free of any microbial contaminants |
Superoxide radicals | Molecules formed during the incomplete reduction of oxygen during electron transport in aerobes and during metabolism by anaerobes in the presence of oxygen |
Thermophiles | Heat loving bacteria |
Traceelements | A chemical element required in small amount for growth |