Chapter 7 Flashcards
basic requirements for life
Bioelements
substance (element or compound)
an organism must get from a source outside its cells
Essential nutrients
contain carbon and hydrogen atoms
and are usually the products of living things
Organic nutrients
atom or molecule that contains a
combination of atoms other than carbon and hydrogen
Inorganic nutrients
must obtain carbon in an organic form
such as proteins, carbohydrates, lipids, and nucleic acids
made by other living organisms
Heterotroph
Produce oxygen and use chlorophyll as the primary pigment
Oxygenic photosynthesis
an organism that uses CO2, an inorganic
gas, as its carbon source
Autotroph
gain energy from chemical compounds
Chemotroph
uses CO2 as source
Autotroph
What are the two categories of chemoorganotrophs?
Saprobes and symbionts
survive totally on
inorganic substances
Chemoautotrophs (lithoautotrophs)
no oxygen but sulfur production, use bacteriochlorophyll as pigment
Anoxygenic photosynthesis
a kind of chemoautotroph, produce
methane gas under anaerobic conditions
Methanogens
free-living microorganisms that feed on organic
detritus from dead organisms
Saprobes
derive nutrients from host
* Can obtain nutrients from living or nonliving source
* Some are obligate parasites
Symbionts
If an organism is degrading large organic molecules to get
both carbon and energy, it would be best described as a:
A. Photoheterotroph
B. Photoautotroph
C. Chemoorganotroph
D. Chemoautotroph
C. Chemoorganotroph
does not require energy; substances
exist in a gradient and move from areas of higher
concentration toward areas of lower concentration
Passive transport
cannot grow without oxygen
Obligate aerobe
utilizes oxygen but can also grow
in its absence
Facultative anaerobe
lacks the enzymes to detoxify
oxygen so cannot survive in an oxygen environment
Obligate anaerobe
requires only a small amount of oxygen
Microaerophile
utilizes oxygen and can detoxify it
Aerobe
require a high concentration of salt
Osmophiles
does not utilize oxygen
Anaerobe
grows best at higher CO2 tensions than
normally present in the atmosphere
Capnophile
do not utilize oxygen but can
survive and grow in its presence
Aerotolerant anaerobes
grow within range of pH 5.5 to 8
Neutrophiles
grow optimally in solutions of 25% NaCl but
require at least 9% NaCl
Obligate halophiles
do not require high concentration of
solute
Osmotolerant –
remarkably resistant to salt
Facultative halophiles
can survive under extreme pressure and will
rupture if exposed to normal atmospheric pressure
Barophiles –
Members cooperate and share nutrients
Syntrophy
Some members are inhibited or destroyed
by others
Amensalism
both members benefit
Mutualism –
can be separated and live apart
Nonobligate Mutualism
commensal benefits, other member
neither harmed nor benefited
Commensalism
require each other to survive
Obligate Mutualism
Division of bacterial cells occurs mainly through
binary fission
When organisms are free-living in a shared habitat
Non-symbiotic
Each new fission cycle increases the population by a factor
of __
2
