2. Cell Boundaries
Every living cell exists in liquid
environment.
There is liquid on the inside and outside
of a cell.
One of the most important functions of
the cell membrane is to regulate the
movement of molecules from one side
membrane to the other side.
4. Diffusion
Movement particles from high to low
concentration.
Diffusion will occur until equlibrium is reached.
This process does NOT require cellular energy
(ATP).
5. Osmosis
Diffusion of water
across cell
membrane from
high to low
concentration.
Water molecules
can very easily
pass through cell
membranes,
because they are
small.
6. Solution Concentrations
The cytoplasm of a cell is solution of many
substances dissolved in water.
A solution is mixture of two or more
substances.
The substances dissolved in a solution are
called solutes.
The concentration of solution refers to
amount of solute dissolved in liquid
(solvent).
8. Environment of the Cell
The solution concentration outside the
cell will determine the direction water
moves across the cell membrane.
The terms hypotonic, hypertonic, and
isotonic are ADJECTIVES! They
describe the environment of the cell!!!
9. Hypertonic Environments
Low concentration of water/High
concentration solutes outside cell.
Water diffuses out of the cell and cell
shrinks.
10. Hypotonic Environments
High concentration of water/Low
concentration solutes outside cell.
Cells swell with water and may
explode.
11. Isotonic Environment
Equal concentration of water/solutes
inside and outside the cell.
Water will move equally in/out cell.
12.
13. 96% Water, 4% salt
98% Water, 2% Salt
97% Water, 3% Salt
95% Water, 5% Salt
98% Water, 2% Salt
98% Water, 2% Salt
14. Osmotic Pressure
Water pressure that builds up inside a cell due
to a hypotonic environment.
If pressure is too high, what could happen?
Osmotic pressure in plants = turgor pressure.
Cell Wall helps to with stand turgor pressure.
16. Facilitated Diffusion
Some particles
are too large to
pass through the
membrane.
They need help
from channel
proteins.
This process
does NOT
require energy!
Glucose
Channel
Protein
18. Active Transport
Occasionally, particles need
to move “against the
concentration gradient.”
Particles moving from low to
high concentration.
Requires energy (ATP).
19. Endocytosis
Type of active transport.
Process of taking in large amounts of
food or liquid by means of active
transport.
1. Phagocytosis (cell eating) – Taking in
large clumps of food.
2. Pinocytosis (cell drinking) – Taking in
large amounts of liquid.
20. Exocytosis
Type of active
transport.
Forcing contents out
of the cell.
Method of removing
large amounts of
waste from cell.