Page 82 - The Miracle in the Cell Membrane

The Miracle in the Cell Membrane

part ments. Due to its pro tec tive struc ture, hydro pho bic
micro-envi ron ments inde pend ent of water and of vital
impor tance to life can form with in the cell. A great many
activ i ties essen tial to the main te nance of life can occur
only in water-free envi ron ments. In con clu sion, were it
not for the hydro pho bic prop er ties of lip ids, car bon-
based life would be impos si ble. This is yet anoth er one of
a great many prop er ties espe cial ly cre at ed for life to exist.

Why Is It Important That the Cell
Membrane Is Fluid?

One of the vital prop er ties of the lipid bilay er (or dou -
ble layer) mem brane is that it's not solid but fluid. With
its flaw less fluid char ac ter, it con stant ly sur rounds the
dis or dered and mobile cyto plasm. Protein mol e cu les in
the mem brane along the sur face of the cell are able to
change pla ces. These mol e cu les' abil i ty to extend along
the mem brane per mits free pas sage through the mem -
brane of cer tain spe cial sub stan ces, as you shall see in
detail fur ther on.
The cho les ter ol mol e cu les in the cell mem brane are
lip ids defin ing the mem bra ne's flu id i ty and are present
in a dis solved state in the dou ble-layer lipid mem brane.
Their main func tion is, by main tain ing the flu id i ty of the
cell mem brane, to increase per me a bil i ty against sol u ble
sub stan ces in body flu ids.
In order for the cell to sur vive, the cell mem brane
must pos sess this flu id i ty. Lowering the tem per a tures of

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