Term
| What are the 4 components of a cellular membrane? |
|
Definition
1.) Phospholipid bilayer
2.) Tramsmembrane proteins
3.) Interior protein network
4.) Cell surface markers |
|
|
Term
| What changes the fluidity of the ceulluar membrane? |
|
Definition
|
|
Term
| What does the trransmission electron microscope show? |
|
Definition
| Cross sections through specimens and internal detail. |
|
|
Term
| What does free-fracture microscopy show? |
|
Definition
| Reveal the inside of a membrane. |
|
|
Term
| What does the fluid mosaic model consist of? |
|
Definition
Phospholipids arranged in a bilayer and globular proteins inserted in the lipid bilayer.
Pieces of foam in a pool float around on the surface of the water. |
|
|
Term
| What is the fluidity of the phosopholipid bilayer effected by? |
|
Definition
1.) fatty acid saturation
2.) Temperature
3.) sterols. increase/decrease fluidity depending on temp. |
|
|
Term
| What are the fxns of membrane proteins? |
|
Definition
1.) transport
2.) enzymes
3.) cell receptor
4.) identity marker
5.) adhesion
6.) anchoring to cytoskeleton |
|
|
Term
| Diverse ______ arise from diverse ________ of membrane proteins. |
|
Definition
|
|
Term
| What do peripheral proteins do? |
|
Definition
| Anchor molecules attaching membrane proteins to surface |
|
|
Term
| How are membrane proteins bonded to the phospholipid bilayer? |
|
Definition
|
|
Term
| Peripheral membrane proteins are attached to a phosophilipid and possess _____ regions that are inserted in the interior of the lipid bilayer. |
|
Definition
|
|
Term
| Intergral membrane proteins have ________ regions embedded within the bilyaer and _______ regions protrude from both sides of the bilayer. |
|
Definition
|
|
Term
|
Definition
| Cylinder of many adjacent beta sheets. The polar interior creates a pore through the membrane and the nonpolar extrior anchors it in membrane. The interior allows passage of water and small polar molecules. |
|
|
Term
| What is passive transport? |
|
Definition
| Movement of molecules through the membrane in which NO ENERGY IS REQUIRED, MOLECULES MOVE IN RESPONSE IN CONCENTRATION GRADIENT. |
|
|
Term
|
Definition
| Movement from high concentration to low concentration. |
|
|
Term
| What is the major barrier to crossing a biological membrane? What happens because of this? |
|
Definition
| The hydrophobic/nonpolar interior. The nonpolar molecules will continue to move until the concentration is equal on both sides. |
|
|
Term
| What is selective permeability? |
|
Definition
| Integral membrane proteins allow the cell to be selective about what passes through the membrane. |
|
|
Term
|
Definition
| Allow the passage of ions. |
|
|
Term
| What does an ion channel require to work? |
|
Definition
| A concentration gradient. |
|
|
Term
| How do gated channels work? |
|
Definition
| Open or close in response to stimulus (chem or electrical) |
|
|
Term
| What 3 conditions determine direction? |
|
Definition
1.) relative concentration on either side
2.) voltage differences across membrane
3.) gated channels - open or closed |
|
|
Term
| What are carrier proteins? |
|
Definition
| Bind to the molecule that they are transporting across the membrane. Changes tertiary structure. |
|
|
Term
| What is facilitated diffusion? |
|
Definition
| Movement of a molecule from high to low concentration with the help of a carrier protein. |
|
|
Term
| What are 3 characteristics of facilitated diffusion? |
|
Definition
1.) specific
2.) passive
3.) saturates when all carriers are occupoed |
|
|
Term
| Why is facilitated diffusion slower? |
|
Definition
| Because a protein can only move one substance at a time. |
|
|
Term
|
Definition
|
|
Term
| What is the substance in water? |
|
Definition
|
|
Term
|
Definition
| The movement of WATER from an area of high WATER concentration to an area of low WATER concentraton. |
|
|
Term
| A high concentration of H2O means how much solute? A low concentration of H2O means what? |
|
Definition
- Low solute concentration/ more H2O
- High solute conentration/ less H2O |
|
|
Term
|
Definition
| High solute/low h2O concentration |
|
|
Term
|
Definition
| Low solute/ high H2O concentration |
|
|
Term
|
Definition
|
|
Term
| What happens to a cell in a hypertonic solution? |
|
Definition
| the water leaves the interior of the cell and causes it to shrivel |
|
|
Term
| What happens to a cell in a hypotonic solution? |
|
Definition
| the water enters the cell and causes it to burst |
|
|
Term
| How is water balance achieved? |
|
Definition
1.) extrusion - water ejected through vacuoles
2.) Isomotic regulation - keeping cells isotonic with enviro
3.) Turgor pressure - plant cells. push the cell membrane against the cell wall to keep it rigid. |
|
|
