Review for Cell Membrane Structure & Molecular Movement Quiz!

Selectively Permeable Controls what goes into and out of the cell! Cell Membrane Nonpolar Inside Cell Outside Cell

Cell Membrane Polar = Hydrophilic → Water Loving Nonpolar = Hydrophobic → Water Fearing

Polar phosphate group Nonpolar tail

What is the cell membrane made of? Phospholipid Bilayer (polar head & nonpolar tail) Proteins Cholesterol Carbohydrates (attached to phospholipids & proteins)

Cell Membrane The cell membrane blocks… -All Ions (charged molecules) -Most polar molecules -Large molecules What are ions? Name a polar molecule

Cell Membrane The cell membrane does NOT block… Nonpolar molecules CO2 O2

How do the molecules blocked by the cell membrane get through???

With the help of proteins embedded within the cell membrane!

Passive Transport Osmosis & Diffusion

Process moving materials across the plasma membrane Does not require energy from the cell!!! Materials move down the concentration gradient: high concentration → low concentration 3 Kinds: Diffusion, Osmosis, and Facilitated Diffusion Passive Transport

Diffusion The movement of small, non-polar molecules across a membrane Molecules move from areas of high concentration to areas of low concentration (molecules “spread out”)

What will occur in the picture below, relative to diffusion? Diffusion

-Solutes move from a location of high concentration to low concentration. -Solutes reach equilibrium

Osmosis Diffusion of water across a selectively permeable membrane. Water moves from high concentration to low concentration.

What will occur in the picture below, relative to osmosis? osmosis

-Water move from a location of high concentration to low concentration. -Solution reaches equilibrium

Facilitated Diffusion Movement of large or polar molecules through transport proteins Molecules move from high concentration to low concentration Does it require energy?

Active transport Moves large, polar, or charged molecules through transport protein Moves from areas of low concentration to high concentration Requires energy!!

Active transport Important Example: Sodium-Potassium Pump: This is how your nerves send signals!

Review the following table!!

Membrane Transport Types Animation Watch this really really good animation about the types of transportation across a cell membrane!