Biology Questions and Answers
- What are differentiations
of the cell membrane?
In some types of cells, the cell
membrane presents differentiations thatare necessary for the specific functions
of the cells. The main differentiations
are the microvillireinforcement of adhesion and the structuror uniones for
between cells (cell junctions).
Microvilli are projections of the membrane resemblingmultiple external (^)
glove fingers. Tfound in cells of his differentiation istissues where it is
advantageous to increase the size of the
surface arexterior, fea in coor example, in the entericntact with the (^)
(intestinal) epithelium for absorption of
nutrients.
Membrane differentiations foreinforcement of adhesion between cellsr (^)
occur mainly in epithelial tissues where
the need for coverage andimpermeability requires cells to be (^)
“glued” to neighboring cells. These
differentiationsdesmosomes, tight ju can be interdigitations,nctions (zonula
occludens), zonula adherens (adherens
junctions) and gap junctions.
- What is the relationship
between concentration
gradient and active and
passive transport?
Passive transport is the movement of
substancesof their conce across membranes in ntration gradient, i.e.,favor
from a more concentrated region to a
less concentrated transport, on the other hand, is theregion. Active (^)
transport of substances across
membranes against their concentration
gradient, from a less concentrated more concentrated region. In passiveto a
transport, because it is spontaneous,
there is no energy spent; the activetransport however requires energy
(work) to occur.
Active transpoincrease the concentration grt works to maintain oradient of ar (^)
substance bepassive transport actstween two in a maregions wnner tohile (^)
reduce the concentration gradient.
- What are the three main
types of passive transport?
The three main types of passive
transport are simple dand facilitated diffusion.iffusion, osmosis - What is the energy source
used in active transport
through biological
membranes?
The energy necessarytransport (against the concentration for active (^)
gradient of the transported substance)
to occuactive transpr comes fortationrom ATP m uses cholecules. Temical he
energy from ATP.
- What is the difference
between simple and facilitated
diffusion? Facilitated by which
type of molecule does the
term “facilitated” mean?
http://www.biology-questions-and-answers.com