2. Membrane Structure
O Semipermeable
membrane.
O Allows some
molecules through,
but not others.
3. Passive Transport
O When molecules
move across the
cell membrane
without the need of
energy.
O Diffusion
O Facilitated
diffusion
O Osmosis
4. Difusion
O Small molecules
like oxygen or
carbon dioxide
cross the cell
membrane.
O They move towards
the side with less
concentration in
order to equal
concentrations.
5. Osmosis
O It is the movement of water across a partially
permeable membrane from a dilute solution to a
concentrated solution.
6. Practice Activities
Order the following cups of water from the most
concentrated to the most diluted
a b c
7. Practice Activities
Draw the arrows indicating in which direction water will move:
Semipermeable
membrane
8. Active Transport
O The movement of
molecules across
the cell membrane
against
concentration
gradient.
O Requires the use of
energy.
10. LAB ACTIVITY
O Objective: to observe that osmosis takes
place across the cell wall and membrane
of plant cells.
O Hypothesis
O Context
O Materials
O Procedure
