Also known as the cell membrane – It is so fun!

 To regulate/control what enters and exits the cell. What types of things can get in and out of the cell from passing through the lipid bilayer (without using a protein)? - Tiny non polar molecules (carbon dioxide and oxygen) -water goes through aquaporins

 Through proteins (integral or transmembrane proteins)

*Know the diagram of a plasma membrane - Phospholipid - Phosphate head is hydrophilic (likes polar molecules like water) - Lipid tail is hydrophobic (prevents molecules like water from crossing the membrane) - Proteins – channel for molecules like water to cross the plasma membrane

 How does the plasma membrane regulate what crosses the cell membrane?  What can cross the cell membrane without using a protein?

1. What types of molecules can cross the cell membrane without using a protein? 2. What types of molecules must use a protein to cross the cell? 3. Draw a phospholipid and name the part that is hydrophilic. Which part is hydrophobic? 4. Explain how the plasma membrane regulates what enters and exits the cell.

 Direction the molecules want to go

 Solutes move from a high concentration gradient to a low concentration gradient.  Passive transport/Diffusion: Molecules that cross the cell membrane without using a protein  Carbon dioxide  Oxygen  Facilitated Transport: molecules move through a protein  Active transport: molecules move against the concentration gradient (low to high)  Must use energy (ATP)

 When water crosses the membrane  Water crosses the membrane so that the solute : water ratio will be in equilibrium

 Explain what concentration gradient and equilibrium have to do with homeostasis  Must use the following vocabulary words: concentration gradient, diffusion, homeostasis, protein, membrane, equilibrium

 Size: Surface Area and volume  The relationship between surface area and volume controls cell size. As a cell gets larger, its volume increases faster than its surface area if the cell maintains the same shape.  Concentration Gradient  More solutes allow for more transport  Energy Use  ATP is needed for Active Transport

Take a look at iology1111/animations/flagellum.html iology1111/animations/flagellum.html