Active and Passive Transport

Passive Transport Movement of substance through the cell membrane without the input of energy Three types – Diffusion – Osmosis – Facilitated diffusion

Diffusion The random movement of molecules from an area where there is relatively fewer of them Continues to happen until the amount in both areas is equal =EQUILIBRIUM

Osmosis Osmosis= the diffusion of water through a cell membrane

Facilitated Diffusion Facilitated diffusion- transport proteins in the cell membrane are used to move substances in and out of the cell – For example: Glucose molecules are too big to enter without the help of transport proteins

Active Transport Sometimes a substance needs to enter a cell even though there is a greater amount of that substance outside the cell than inside – Cell needs energy to move the substance inside Active transport- when an input of energy is required to move materials through a cell membrane – Involves proteins

How it Works Active transport requires transport proteins, which bind with the needed particle and cell energy is used to move it through the membrane

Active Transport

Let’s Review!

Endocytosis Some molecules or substances are too BIG for diffusion or transport proteins The cell membrane must fold in on itself, enclosing the substance in a vesicle The vesicle pinches off and enters the cytoplasm, acting as a transport and storage structure This process is call ENDOCYTOSIS

Exocytosis How the cell releases what’s in the vesicle The OPPOSITE of endocytosis The vesicles membrane fuses with the cell membrane’s, and the vesicle contents are released Video time!

Exit Ticket Compare and contrast facilitated diffusion and active transport. Do you have any questions or things you don’t understand?