Bacteria and Digestion
Name: Pamela S.
What bacteria is involved in
digestion? or in the digestion of indigestible food? For example Celery
is indigestible right?
Therefore bacteria eats it up rather than the
stomach digesting it, what kind or type of bacteria does that? and why?
Bacteria are indispensable for food digestion. In a
simplified view, food is degraded in the stomach by
acids, then the bile destroys fats, and bacteria in
the intestines degrade large biomolecules further into
smaller ones that can pass the intestinal surface.
Bacteria produce certain enzymes that can degrade
biomolecules that higher organisms don't produce. A
classical example are herbivores: they can only eat
grass because of their bacteria that can degrade it.
Or white ants that can eat wood because of the
bacteria they carry. We are just as dependent on our
native microflora in our gut.
Both Gram-positive and
Gram-negative bacteria are present in our intestines,
and there are many kinds of bacteria present at the
same time. The bacteria florish on our food, but their
products are again food for us, so who is eating what?
Bacteria that live in a host and are beneficial to
that host, at the same time being fed by that host are
called commensals. If the bacteria would only be able
to live in that host, and the host would be completely
dependent on that kind of bacteria, it would be called
Actually humans don't contain the bacteria necessary to digest cellulose.
Cows and other ruminants do and therefore they can digest cellulose.
Interestingly, termites aren't able to digest cellulose either. They have a
symbiotic relationship with a bacterium that lives in their guts. The
bacteria get a source of food, and they break down the cellulose into
something that the termites can digest.
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Update: June 2012