Section 3: Cell Transport

I. Cell Membrane Cell membranes are made of phospholipids bilayer. Semipermeable- they allow some but not all materials to enter and exit the cell Provides a barrier that separates the cell from the external environment. Aides in protection and support. Aides in communication between other cells.

II. Cell Membrane Structure: 1. Phospholipids= Phosphate Head= Hydrophilic Fatty Acid Tail= Hydrophobic (soluble or not soluble?) Interacts with water!

II. Cell Membrane Structure: Proteins= In phospholipid bilayer to act as a gate or channel for things that are to big to go threw phospholipids Carbohydrates= Attached to some protein channels as long carbohydrate chains to serve as ID cards of the cell; allowing the cell to communicate and recognize other cells.

III. Cell Transport Movement Across the Plasma Membrane A few molecules move freely Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules Proteins embedded in lipid bilayer Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins

III. Cell Transport There are 2 kinds of transport in cells: 1. Passive Transport= movement of substances without requiring any energy to be put in. Moves from High Concentration to Low Concentration [ ] [ ] Diffusion= The movement of molecules from areas of high concentration to low concentration (from areas of lots of stuff to areas of not so much stuff) Facilitated Diffusion= movement of large molecules through protein channels Osmosis= a type of diffusion that involves the movement of only WATER.

III. Cell Transport There are 2 kinds of transport in cells: 2. Active Transport= movement of substances WITH requiring energy to be put in. Uses energy in the form of ATP. Moves from Low Concentration to High Concentration [ ] [ ]

THE END!

Next: We are going to do a lab activity over diffusion and osmosis. First, take ten minutes and read the whole thing then answer the Pre-lab and experiment questions. You make work in groups.

Quick Quiz What is the difference between a eukaryote and a prokaryote? What are the differences of a plant cell versus an animal cell? What does active transport need that passive transport does not?