Lipids Don’t Mix with Water
Fats and oils are members of a large chemical
family called the lipids, a term that comes
from the Greek for “fat.” Fats and oils are
invaluable in the kitchen: they provide flavor
and a pleasurable and persistent smoothness;
they tenderize many foods by permeating and
weakening their structure; they’re a cooking
medium that allows us to heat foods well
above the boiling point of water, thus drying
out the food surface to produce a crisp texture
and rich flavor. Many of these qualities reflect
a basic property of the lipids: they are
chemically unlike water, and largely
incompatible with it. And thanks to this
quality, they have played an essential role in
the function of all living cells from the very
beginnings of life. Because they don’t mix
with water, lipids are well suited to the job of
forming boundaries — membranes —
between watery cells. This function is