1. Cellular Transport
Biology 2017

2. Cellular Transport
Every living cell exists in a liquid environment that it needs to survive.
The plasma membrane is selectively permeable.
This means only certain molecules are allowed in and out of cells.

3. Diffusion Notes
Diffusion- particles tend to move from an area where they are more concentrated to an area less concentrated.
Facilitated diffusion- molecules that cannot diffuse on their own that move through protein channels in the cell membrane.

4. Egg Experiment on YouTube
Osmosis ctd…
Osmosis effects cells depending on the type of solution that they are in: isotonic, hypertonic, or hypotonic.
Egg Experiment on YouTube
Isotonic- solution which the concentration is the same inside AND outside the cell.
Hypertonic- solution that has more water inside the cell than outside, so water moves out causing the cell to shrink.
Hypotonic- solution that has more water outside the cell than inside, so water moves in causing the cell to swell.

5. Types of Transport
Passive Transport- in cells, substances can diffuse across membranes WITHOUT requiring the use of energy.
Active Transport- transport protein (aka carrier protein) REQUIRES energy to help move particles across the membrane against a force.
This is known as a concentration gradient.

6. Endocytosis vs Exocytosis
Large particles are engulfed, then enclosed by a cell membrane as it moves into the cell.
Large particles are released from a cell by secreting them or expelling them.

7. Osmosis and Homeostasis
Osmosis- the diffusion of water across a selectively permeable membrane.
Homeostasis- enables the cell membrane to regulate the cell’s internal environment.

8. Follow Up
Does a cell use passive transport or active transport to move molecules? Both Depending on the molecule and if it needs to move against the concentration gradient.