Page 78 - The Miracle in the Cell Membrane

The Miracle in the Cell Membrane

exam in ing in detail, is essen tial for bod i ly func tions, and
there fore for life itself.
Phospholipid mol e cu les are irre place a bly impor tant
with regard to their arrange ments in the cell mem brane.
The cel lu lar biol o gist John Trinkaus com ments about the
mol e cu le's unique struc ture:

Because water is itself a strong ly polar phos phate of the mem -
brane, lip ids will inev i ta bly be attract ed to the sur fa ces of the
mem brane, both exter nal and cyto plas mic. And just as inev i -
ta bly, their non-polar fatty acid parts will tend to be squeezed
into the inte ri or of the mem brane. . . . Simply because of their
intrin sic chem i cal nature, phos phol i pids nat u ral ly and spon -
ta ne ous ly self-assem ble to form a bi-layer in a watery solu -
tion. 26
As you see, every thing is in the right place and the
right form. How do the mol e cu les form ing the cell mem -
bra ne's phos phol i pid struc ture know where they need to
be dur ing the mem bra ne's con struc tion? In fact, the mol -
e cule has the ideal pur pose-direct ed struc ture. Moreover,
no known sub stance can replace this spe cial struc ture.
The fea tures of vis cos i ty and lack of per me a bil i ty abso -
lute ly must be present in any mem brane sys tem sur -
round ing the cell. Yet these fea tures are found togeth er
only in the dou ble-lay er ed lipid mem brane. To a large
extent, the cell's very exis tence depends on the bio chem -
i cal and bio phys i cal prop er ties of this dou ble-lay er ed
lipid mem brane.
In the pres ence of water, lip ids and phos phol i pids
line up along side one anoth er and can form lay ers or

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