160 likes | 244 Views
Do Now 11/10. Glycerol is a straight-chain carbohydrate with the formula C 3 H 8 O 3 . Draw its structure. The Cell Membrane (aka Plasma Membrane). Every cell has a membrane around it It protects the cell It allows nutrients to enter and wastes to leave
E N D
Do Now 11/10 Glycerol is a straight-chain carbohydrate with the formula C3H8O3. Draw its structure
The Cell Membrane (aka Plasma Membrane) • Every cell has a membrane around it • It protects the cell • It allows nutrients to enter and wastes to leave • Membranes are made of 3 types of molecules • LIPIDS • Proteins • Carbohydrates
Membrane Lipid = Phospholipid YOU REMEMBER THE PHOSPHOLIPID RIGHT? Polar Head Two Nonpolar Tails
Let’s take another look: HYDROPHILIC – loves water HYDROPHOBIC – fears water
Water, Water Everywhere… • Ok, so we know that the cell membrane is made mainly of these phospholipids • We also know that there is wateroutside and inside of a cell • Question: How do the phospholipids arrange to create protective barrier for the cell?
A Bilayer!!!! • Phospholipid Bilayer– two rows of phospholipids that surround every cell. HYDROPHILIC HYDROPHOBIC HYDROPHILIC
Put It All Together • Remember: The membrane is made of 3 major molecules, not only LIPIDS!
Semipermeability • The purpose of the external membrane of the cell is to allow only certain molecules to enter, while allowing wastes to exit:
Remember the three domains of life? • Bacteria and Archaea are domains of unicellular prokaryotes. • What’s so different about them anyway?
One difference is the membrane lipids! • Unlike other organisms, archean cells use ether linked (-OH : -OH) lipids in their membranes. Also, the “tails” are funky. • Take home: archea have weird membrane lipids
Membrane fingerprints • Long chains are more like butter (for high temps) • Short chains are like oil (cold temps)
The Basics are as easy as 1. hydrophilic heads 2. hydrophobic tails 3. phospholipid bilayer!