Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


Simple diffusion is the direct passage of


substancesfavor of their concentration gra across the membrane indient. In (^)
facilitated diffusion the movement of
substancesconcentration g is also in favor of theirradient but the
substances move bound to specific
molecules that acti.e., facilitators of their passage as “permeabilizers”,through (^)
the membrane.



  1. How does the intensity of
    simple diffusion vary in
    relation to the concentration
    gradient of the moved
    substance?


The higher the concentrationa substance the more intense gradient ofits simple
diffusion will begradient diminishes th. If the concentratione intensity of
simple diffusion diminishes too.



  1. How does the intensity of
    facilitated diffusion vary in
    relation to the concentration
    of the moved substance? What
    is the limiting factor?


Like simple dis more intense when the concentrationiffusion facilitated diffusion
gradient of the substance increases and
less intense when the gradient lessens.In facilitated diffusion however there is
a limiting factor: the quantity of the
permeases that facilitatethrough the membrane. Even in a the trans port
situation in which the concentration
gradient of the diffusing substanceincreases, if there are not enough
permeases to perform the transport


there will be no increase in the intensity

of the diffusion. This situation is callesaturation of the transport proteins and (^) d
it represents the point at which the
maximum substance acrosstransport capacity the membrane is of the
achieved.



  1. Without saturation of
    transport proteins and under
    the same concentration
    gradient how can the speed of
    simple diffusion be compared
    to the speed of facilitated
    diffusion?
    The action of facilitator proteins in
    facilitated ddiffusion faster iffusion makes tthan simple diffusionhis type of
    under equal concentration gradients of
    the moved substance.

  2. How does facilitated
    diffusion present similarities
    with enzymatic chemical
    reactions?
    One of the main examples of facilitated


transport is the entrance of glucosefrom the blood into cells. Glucose from (^)
blood binds to specific permeases
(hexose-transportinpresent in the cell membrane and byg permeases) (^)
diffusion facilitated by these proteins it
enters thfunctions.e cell to play its metabolic
Facilitatedcatalysis because the transp diffusion resembles chortedemical
substancessubstrates bind to enzymes and in bind to permeases like (^)
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