Cell Transport

Passive transport (requires no ATP as molecules move along a concentration gradient):

• Simple Diffusion
• Facilitated Diffusion
• Osmosis

Active transport (requires ATP as molecules move against a concentration gradient):

•  Endocytosis
•  Exocytosis
•  Pinocytosis (“drinking”)
•  Phagocytosis

Simple Diffusion

• Net movement of molecules in and out of the cell along a concentration gradient
• Eg. gas exchange during photosynthesis, gas exchange at the alveoli 

Facilitated Diffusion

• Movement of specific molecules down a concentration gradient through specific carrier proteins
• Molecules that move by facilitated diffusion include glucose and amino acids

Osmosis

• Net movement of water molecules from a region of higher water potential to a region of lower water potential, across a partially permeable membrane
• Eg. absorption of water by plant roots

credits to: http://www.biologymad.com/resources/diffusionrevision.pdf