1. Transport across the plasma membrane

2. Structure of the plasma membrane
This diagram shows the currently accepted “fluid mosaic model” for the membrane structure.
The plasma membrane is made of of a phospholipid bilayer (two layer). The membrane has many proteins embedded in it, some forming protein channels.
The plasma membrane regulates what enters and leaves the cell. Many molecules cross the cell membrane constantly to supply the cell with its needs and remove its wastes.

4. The plasma membrane is partially/selectively/differentially permeable
Materials can cross the membrane in different ways.
Large amounts of material requires bulk transport via endocytosis/exocytosis
Small (molecular) amounts move in and out of cells via:
Diffusion
Facilitated diffusion
Osmosis
Active transport

5. Endocytosis
Endocytosis is the cellular uptake of molecules and other substances by regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle.

6. Exocytosis
Exocytosis is the secretion of macromolecules by the fusion of vesicles with the plasma membrane.

7. Diffusion
Simple diffusion is the movement of substances form a higher-concentration region to a lower-concentration region.

8. Facilitated diffusion
Facilitated diffusion is the movement of substances from a higher-concentration region to a lower-concentration region with the assistance of an integral protein across a selectively permeable membrane.

9. Osmosis
Osmosis is the net movement (diffusion) of a solvent (water in living organisms) from a region of higher water concentration to a region of lower concentration.

10. Tonicity is a relative term
Hypotonic Solution - One solution has a lower concentration of solute than another.
Hypertonic Solution - one solution has a higher concentration of solute than another.
Isotonic Solution - both solutions have same concentrations of solute.

11. Plant and Animal Cells put into various solutions

12. Osmosis and Animal Cells
NO CHANGE
CRENATION
WILL LYSE

13. Active Transport
Active transport is the net movement of dissolved substances through a cell membrane against its concentration gradient (from low to high concentration). This is a process requiring metabolic energy.