Page 87 - The Miracle in the Cell Membrane
P. 87
(a) THE CELL
Cell membrane
Carbohydrate
bonds
Cell
ble-layered{
mem-
brane,
consisting
of a dou-
phospho-
lipid layer
(b) Membrane protein
passing inside the cell
membrane
(c) Enlarged view of spiral sections
passing through the membrane
In 1972, S. Jonathan Singer and Garth Nicholson of California University pro-
posed a model to describe the relationship between the proteins and lipids in
the cell membrane. They compared the proteins to icebergs floating in a sea of
lipids, saying that part of these proteins—the tips—were folded above or
beneath the cell membrane, and that the protein's middle part was buried inside
the membrane. It is known that proteins consisting of such three regions play
important roles in biological processes. One of them was examined in detail fol-
lowing Singer and Nicholson's liquid-mosaic model.
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