2. Look at the diagram below.
a. How is the concentration gradient in
the capillary maintained?
b. Why is this useful?
Extension 2
is this useful?
Small blood vessels.-
called capillaries, have
walls just one cell thick.
Oxygen molecules
(not shown) diffuse
out of the
capillary.
Glucose
molecules (not
shown) diffuse
out of the
capillary.
The continual flow of
blood maintains the
concentration gradient.
nucleus
There is an overall
movement of carbon
dioxide molecules
down their concentration
gradient.