physiology 6

Extends into or through the lipid bilayer and are firmly embedded it it. ( most are transmembrane proteins)

polar portion water loving

• non polar portion
• water fearing
• 2 long fatty acid chains

• span the entire lipid bilayer and protrude into the cytosol
• includes channels that allow ions to cross the membrane

not as firmly embedded, loosely bount to the membrane by associations

• proteins with an attacthed carbohydrate group at the end of the protein that protrudes into the extracellular fluid
• enables a cell to recognize other cells of same kind or to recognize and respond to dangerous foreign cells
• located mainly on the extracellular surface

Any material that causes an immune response

• called so because of the presence of proteins that are dispersed in the bilayer
• consists of phospholipids, cholesterol, proteins and carbs

• the fatty acid "tails" are hydrophobic/non polar
• the "head" is hydrophilic/ polar

loosely bound to the membrane by associations with integral membrane proteins or phospholipids

extend into or through the lipid bilayer and are firmly embedded in it

• Spans the entire lipid bilayer and protrudes into the cytosol
• includes channels that allow ions to cross the membrane

interferes with hydrophobic interactions between phospholipid tails, which may cause crystallization of the bilayer and may decrease fluiditity

• form ion channels
• act as transporters
• some are enzymes

• serves as a barrier
• blood/brain
• stomach

• Specialized in cell to cell adhesion
• provides strength so cells dont tear apart
• heart, uterus, skin

• Communication junction allows cells to communicate very quickly
• neurons

transportation of molecules across a membrane that requires energy

able to move across a membrane with ease

unequal distribution of ions

movement of material from high concentration to low concentration

Diffusion of water across a membrane

pathway that allows for movement of material from one end to another

unequal charge distribution across the membrane

a difference in electrical potential or voltage that appears across the membranes of most cells

the sum of the electrical and chemical gradients acting on an ion or charged molecule

the passive movement of molecules across a membrane by way of a transport protein

• separates the cell from the extracellular fluid
• contains the organelles of the cell
• allows for some permeability
• movement of ions in or out

• size of channel
• charge of interior portion of channel
• shape of diffusing molecule
• temperature
• membrane thickness
• lipid solubility

• requires energy
• moves against concentration gradient

passive moves with gradient

Passive transport

active transport

• the pump works to reestablish sodium concentrations outside the cell and potassium concentrations inside the cell after an action potential.
• It uses energy to pump 3 na out and to put 2 k in.

Molecules in the extracellular fluid enter the cell through the formation of vesicles called endosomes( from the plasma membrane)

• cell eating
• cell uses movements of its membrane to form an enclosed phagosome in the cytoplasm
• common in white blood cells for removing foreign particles and bacterial

• membrane indents and pinch together to enclose the particle
• cell drinking
• non specific process and the contents of the vesicle is extracellular fluid containing dissolved solutes

vesicle inside the cell fuses with the membrane and releases its contents into the extracellular fluid