Rotation
of
Carrier
In
this
scheme
the
carrier
molecule
is
believed
to
have
a
diameter
nearly
equal
to
the
thickness
of
the
membrane.
The
substance
to
be
transported
binds
to
the
carrier
molecule,
forming
a
carrier
substrate
complex
This
rotates
through
180°
and
releases
the
substance
on
the
other
side
of
the
membrane
Jacques
Monod
and
his
associates
studied
the
transport
of
lactose
(milk
sugar)
across
the
cell
membrane
of
the
bacterium
E.
coli.
This
bacterium
accumulates
lactose
500
-
1000
time
against
the
Concentrations
gradient
