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Chapter 5 - Bio 111
Test 1
35
Biology
Undergraduate 3
09/23/2013

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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
Cholesterol
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
functions/structures
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
covalently
Term
Peripheral membrane proteins are attached to a phosophilipid and possess _____ regions that are inserted in the interior of the lipid bilayer.
Definition
nonpolar.
Term
Intergral membrane proteins have ________ regions embedded within the bilyaer and _______ regions protrude from both sides of the bilayer.
Definition
nonpolar/polar
Term
What is a beta barrel?
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
What is diffusion?
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
What do ion channels do?
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
What is water?
Definition
The solvent
Term
What is the substance in water?
Definition
The solute
Term
What is osmosis?
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
Hypertonic means?
Definition
High solute/low h2O concentration
Term
Hypotonic means?
Definition
Low solute/ high H2O concentration
Term
Isotonic means?
Definition
Equal concentration
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.
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