Opening Activity 11/3/15 Scientists refer to the cell membrane as a fluid mosaic model. What is a mosaic? (hint: the pictures below are mosaics)

Parts of the cell membrane Essential question: What are the components of a cell membrane, and how do they work?

Overview Cell membrane separates living cell from nonliving surroundings Controls traffic in & out of the cell – selectively permeable – allows some substances to cross more easily than others

Phospholipid Phosphate group head – Contains a phosphate – Hydrophilic – loves the water Fatty acid tails – Contain carbon and hydrogen – Hydrophobic – water fearing

Phospholipid bilayer There is water inside and outside the cell Phospholipids arrange themselves with hydrophobic tails on the inside and hydrophilic heads on the outside. Together it is the phospholipid bilayer (bi = two) This is the basic structure of the cell membrane

Proteins: channel or transport Go all the way through the phospholipid bilayer, and have tunnel in the middle Allow molecules to pass through the tunnel part May or may not require energy. May or may not change shape as the molecule goes through.

AP Biology Many Functions of Membrane Proteins Outside Plasma membrane Inside Transporter Cell surface receptor Enzyme activity Cell surface identity marker Attachment to the cytoskeleton Cell adhesion

The cell membrane... ta da! This is just a tiny slice through the cell membrane – remember it covers the whole cell, and it all looks like this if you cut out a piece of it

Cells Video eS4 eS4 9

Finish Build-A-Membrane Make sure your name is on your model and put it in the bin at the front of the room Put the worksheet in the In-Box at the back of the room Clean up & put away all supplies 10

Closing Activity/Exit Ticket You will turn this in! Give Me 5! On a ½ sheet of paper with your name, date, and period, write down 5 words that come to mind when you think about the structure of the cell membrane (individual words, not a sentence)