Chapter 7
Terms
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- heterotroph
- acquires carbon from organic molecues
- generation (doubling) time
- the time required for a complete fission cycle - from parent cell to two new daughter cells.
- minimum temperatures
- the lowest temperature that permits a microbe's continued growth and metabolism; below this temperature, its activities are inhibited.
- mesophiles
- organisms that grow at intermediate temperatures.
- death phase
- phase when the cells begin to die at an exponential rate and most are unable to multiply.
- stationary growth phase
- phase when the population enters a survival mode in which cells stop growing or grow slowly.
- chemoautotroph
- an autotroph that extracts energy from inorganic substances.
- essential nutrients
- substances required for survival. Usually containing the elements (C, H, N, O, P, S, Na, Cl, K, Ca, Fe, Mg)
- exponential growth phase
- a period during which the curve increases geometrically.
- facultative anaerobe
- an aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it. Metabolizes by aerobic respiration when oxygen is present, but in its absence, it adopts in anaerobic mode of metabolism such as fermentation.
- isotonic solution
- have the same solute concentration as the inside of the cell.
- nutrition
- consists of taking in chemical substances and asimilating and extracting energy from them.
- parasite
- feeds from a live host and usually cause harm
- obigate halophile
- requires a salt concentration of at least 15%, but grows optimally in 25%
- quoroum sensing
- an explanation for the development and behavior seen in biofilms. This process occurs in several stages, including self-monitoring of cell density, secretion of chemical signals and genetic activation.
- barophile
- deep sea organisms that exist under pressures that range from a few times to over 1,000 times the pressure of the atmosphere.
- commensalism
- a relationship where one member receives benefits, while its co inhabitant is neither harmed nor benefited.
- binary (transverse) fission
- the splitting of a parent bacterial cell to form a pair of similar sized daughter cells.
- inducer molecules
- accumulate as the cell population grows. Stimulates expression of a particular gene.
- antagonism
- arises when one member of a community attacks other members. In this interaction, one microbe secretes chemical substances into the surrounding environment that inhibit or destroy other microbes in the same habitat.
- lag phase
- an early flat period on the graph when the population appears not to be growing or is growing at less than the exponential rate.
- inorganic nutrient
- an atom or simple molecule that contains elements other than carbon and hydrogen.
- parasitism
- a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat. Multiplication will usually harm the host to some extent.
- optimum temperatures
- covers a small range, intermediate between the minimum and maximum, which promotes the fastest rate of growth and metabolism.
- pathogen
- a parasite that cause damage or death
- mutualism
- exists when organisms live in an obligatory but mutually beneficial relationship.
- group translocation
- molecules are altered during transport.
- growth curve
- a graphic representation of a closed population over time.
- growth factor
- an organic nutrients (amino acid and vitamin) that cannot be synthesized and must be provided.
- microaerophile
- an organism that does not grow at normal atmospheric concentrations of oxygen but requires a small amount in metabolism.
- symbosis
- a general term used to denote a situation in which two organisms live together in a close partnership.
- osmosis
- diffusion of water through a selectively permeable membrane
- halophile
- thrives in hypertonic surroundings
- micronutrients
- trace elements required in smaller amounts - Zn, Mn, Cu)
- facilitated diffusion
- a form of passive transport that can move specific substances.
- thermophile
- a microbe that grows optimally at temperatures greater than 45 degrees celsius.
- organic nutrients
- contain at least some combination of carbon and hydrogen atoms. They are usually the products of living things.
- exponential
- the growth pattern of doubling time
- synergism
- an interrelationship between two or more organisms that benefits all members but is not necessary for their survival. Together, the participants cooperate to produce a result that noe of them could do alone.
- methanogen
- chemoautotrophs that produce methane
- autotroph
- depends on carbon dioxide for its carbon needs.
- psychrophile
- a microorganism that has an optimum temperature below 15 deg celsius and is capable of growth at 0 deg celsius. It is obligate with respect to cold and generally cannot grow above 20 deg celsius.
- hypotonic solutions
- osmotic changes that affect cells & contain a lower solute concentration
- phagocytosis
- cell eating
- active transport
- substances are taken into the cell by a process that consumes energy.
- maximum temperatures
- the highest temperature at which growth and metabolism can proceed. If the temperature rises lightly above maximum, growth will stop.
- strict (obligate) anaerobe
- an organism that lacks the metabolic enzyme systems for using oxygen in respiration and also lack the enzymes for processing toxic oxygen, they cannot tolerate any free oxygen in the immediate environment and will die if exposed to it.
- macronutrients
- essential nutrients required in larger amounts
- photautotroph
- an autotroph that derives energy from light
- saprobe
- a decomposer that feeds upon dead organic matter
- diffusion
- the natural movement of substances down a concentration gradient and requires no additional energy. (passive transport)
- pinocytosis
- cell drinking
- hypertonic solutions
- osmotic changes that affect cells & contain a higher solute concentration
- aerobe
- an organism that can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products.