Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


Digestive System



  1. What is digestion?


Digestion is the breaking down of larger


organic moldiet, e.g. carbohydrates,ecules obtained from th fats, proteins,e (^)
into smaller ones, like glucose, fatty
acids, glycerol and amino acids.



  1. How different are
    intracellular and extracellular
    digestion? What is the
    evolutionary advantage of
    extracellular digestion?


Intracellular digestion is that in which


the breaking down of macromoleculestakes place within the cell. Extracellular (^)
digestion is that in which
macromolplaces outside ecules arthe cell (in e broken down inthe
extracellular space, in the surrounds, in
the lumen of digestive tubes, etc.)
The advent of extracellular digestion in
evolution from a greater variety oallowed organismsf food. The to benefit
breaking down of larger molecules into
smaller othe use of other foods than thnes outside the cell permittedose that,
due the size of their molecules, could
not be interiorizephagocytosis or pinocytosis.d by diffusion,



  1. How is extracellular
    digestion related to cellular
    and tissue specialization?
    A variety of specialized appeared with extracellularcells and tissues digestion to
    provide enzymes and special structuresfor the breaking down of dietary
    macromolecules.
    This phenomenon allowed other cells tobe liberated for other tasks and
    differentiationsnutrients distributed while benefiting fromthrough the
    circulation.

  2. What is the difference
    between a complete digestive
    system and an incomplete
    digestive system? How are
    these types of digestive tubes
    associated or not to
    extracellular digestion?


Animals with asystem are those in which the n incomplete digestivedigestive (^)
tube has only one opening (cnidarians,
platyhelminthcomplete digestive systemes). Animals with a are those in (^)
which the digestive tube has two
openings, mouth animal phyla, with and anus (all otherthe exception of
poriferans, that do not have any
digestive tube).
In animals with incomplete digestive
tubes the digestion is mixed, the extracellular space and finishes iit begins inn
the intracellular space. In animals with
complete ddigestion within thigestive systemse digestive tu extracellularbe
predominates.
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