Download Chemolithotrophs use electron donors oxidized in the

Chemolithotrophs use electron donors oxidized in the cell, and
channel electrons into respiratory chains, producing ATP.
LEARNING OBJECTIVE [ edit ]
Outline the characteristics associated with chemolithotrophs
KEY POINTS [ edit ]
Chemotrophs are organisms that obtain energy by the oxidationof electron donors in their
environments. These molecules can be organic (chemoorganotrophs)
or inorganic(chemolithotrophs).
In chemolithotrophs, the compounds - the electron donors - are oxidized in the cell, and the
electrons are channeled into respiratory chains, ultimately producing ATP.
The electron acceptor can be oxygen (in aerobic bacteria), but a variety of other electron
acceptors, organic and inorganic, are also used by various species.
TERMS [ edit ]
lithotroph
An organism that obtains its energy from inorganic compounds (such as ammonia) via electron
transfer.
chemolithotroph
chemoautotroph
chemotroph
an organism that obtains energy by the oxidation of electron-donating molecules in the
environment
symbiont
An organism that lives in a symbiotic relationship; a symbiote.
EXAMPLE [ edit ]
Macrofauna and lithotrophs can form symbiotic relationships, in which case the lithotrophs are
called "prokaryotic symbionts". An example of this is chemolithotrophic bacteria in deep
seaworms or plastids, which are organelles within plant cells that may have evolved from
photolithotrophic cyanobacteria-like organisms.
Give us feedback on this content: FULL TEXT [edit ]
A lithotroph is an organism that uses an
inorganicsubstrate(usually of mineral
origin) to obtain reducing equivalents for
use in biosynthesis (e.g., carbon dioxide
fixation) or energy conservation via
aerobic oranaerobic respiration. Known
chemolithotrophs are exclusively
microbes; no known macrofauna
possesses the ability to utilize inorganic
compounds as energy sources.
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Macrofauna and lithotrophs can form symbiotic relationships, in which case the lithotrophs
are called "prokaryotic symbionts". An example of this is chemolithotrophic bacteria in deep
sea worms or plastids, which are organelles within plant cells that may have evolved from
photolithotrophic cyanobacteria-like organisms .
Gollner Riftia pachyptila
Giant tube worms (Riftia pachyptila have an organ containing chemosynthetic bacteria instead of a
gut.
Chemotrophs are organisms that obtain energy through the oxidation of electron donors in
their environments. These molecules can be organic (chemoorganotrophs) or inorganic
(chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which utilize
solar energy. Chemotrophs can be either autotrophic or heterotrophic. Chemoautotrophs
generally fall into several groups: methanogens, halophiles, sulfur oxidizers and reducers,
nitrifiers, anammox bacteria, and thermoacidophiles. Chemolithotrophic growth could be
dramatically fast, such as Thiomicrospira crunogena with adoubling time around one hour.
In chemolithotrophs, the compounds - the electron donors - are oxidized in the cell, and the
electrons are channeled into respiratory chains, ultimately producing ATP. The electron
acceptor can be oxygen (in aerobic bacteria), but a variety of other electron acceptors, organic
and inorganic, are also used by various species. Unlike water, the hydrogen compounds used
inchemosynthesis are high in energy. Other lithotrophs are able to directly utilize inorganic
substances, e.g., iron, hydrogen sulfide, elemental sulfur, or thiosulfate, for some or all of
their energy needs.