5. Complete the sentences to describe some important examples of active transport. The concentration of glucose molecules in the of the
small intestine is than the concentration inside the
intestinal villi. This means that glucose would from the
villi into the lumen, but this can’t happen because the body needs to take
in the glucose, not lose it. Instead, special proteins in
the cell membrane use to move the glucose into the villi
against its gradient.
Similarly, the amount of glucose inside of the blood in the kidneys is
than it is in the tubule, but it must move out of the
tubule. Glucose moves into the blood by
.