​The Cell Membrane is SELECTIVELY PERMEABLE!

​This means that only certain substances can enter or leave the cell.

​

​Just like the gif to the right, only the smaller blue substances can enter and leave the cell, but the green ones cannot.

​Passive Transport:

• ​Does NOT require energy!

• Moves particles from an area of high concentration to an area of low concentratio

​Passive Transport Examples:

​1. Simple Diffusion

​2. Facilitated Diffusion

​3. Osmosis

​Passive Transport: Simple Diffusion

​Simple diffusion allows smaller particles, like oxygen and carbon dioxide, to move through the phospholipid bilayer without assistance.

​Substances move with the concentration gradient. This means they move from high to low concentration.

​Passive Transport: Facilitated Diffusion

​Facilitated Diffusion allows carbohydrates, amino acids, nucleosides, and ions to pass through the cell membrane USING PROTEINS as a doorway.

​Passive Transport: Osmosis

​Osmosis is the diffusion of WATER across the phospholipid bilayer of the cell membrane.

​The smaller particles are water molecules.

​Active Transport

• Requires energy to move particles over the cell membrane.

​

• Moves from low to high concentration. (Against the concentration gradien

​Active Transport: Types

​1. Pumps

2. Vesicle Transport

​Active Transport: Pumps

​Active Transport: Vesicle Transport

​Nutrients including sugars, fatty acids, and amino acids use vesicles to enter and leave the cell.

​Endocytosis moves substances into the cell

​Exocytosis moves substances out of the cell