Lab #3 Osmosis

homeostasis

a stable equilibrium that allows life’s functions to proceed normally and restores balance when a disruption occurs

aquaporins

specialized proteins in which water crosses cell membranes

hydrophobic

water fearing

osmosis

the diffusion of water molecules across semipermeable membranes

diffusion

the movement of substances from an area of high concentration to areas of low concentration

facilitated diffusion

a passive transport process; it does not require the input of energy

solvation

when a substance is dissolved in water some of the water molecules attach to the substance to form a water shell around the substance in this process

solute bound water molecules

the water molecules attached to the substance

membrana

una barrera fluida. a collage of different proteins embedded in the fluid matrix of the lipid bilayer

selective permeability

a characteristic of the cellular membrane. it allows some substances to cross it more easily than others

amphipathic molecules

molecules that contain hydrophobic and hydrophylic regions

fluid mosaic model

states that a membrane is a fluid structure with a mosaic of various proteins embedded on it

j singer and g nicolson

proposed that the membrane is a mosaic of proteins dispersed within the bilayer with only the hydrophilic regions exposed to water

peripheral proteins

proteins that are bound to the surface of the membrane

integral proteins

proteins that penetrate the hydrophobic core

transmembrane proteins

integral proteins that span the membrane

transporte pasivo

transporte que no requiere el uso de energia, va a favor de su gradiente de concentracion

difusion pasiva

difusion en el que pasan moleculas sin cargad ni necesidad de intermediarios

difusion facilitada

difusion pasiva que requiere el uso de proteinas

• mediado por canales

• mediada por proteinss transportadoras

transporte activo

transporte que necesita energia porque va en contra de su gradiente de concentracion

transporte activo primario

tipo de transporte que usa energia del ATP. va en contra del gradiente de concentracion

transporte activo secundario

usa energia del potencial electroquimico. la energia proviene de la transportacion de ambas particulas a la vez almacenada en el diferencial del gradiente electroquimico, va en contra del gradiente de concentracion

simporte

proteina. ambos solutos van al interior, uno de ellos a favor y el otro en contra del gradiente de concentracion

antiporte

proteina. una de las especies fluye de alta a baja concentracion, lo que produce la energia entropica para impulsar el transporte del otro soluto de baja a una de alta concentracion

proteinas de transporte

permiten el paso de sustancias hidrofilicas a traves de la membrana

proteinas de canal

proteina de transporte. poseen un canal hidrofilico que ciertas moleculas o iones pueden utilizar como tunel

carrier proteins

proteinas de transporte. se unen a las moleculas y cambian de forma para transportarlas a traves de la membrana

diffusion

the tendency for molecules to spread out evenly into the available space

presion osmotica

la diferencia de presion de ambos lados de la membrana semipermeable al suceder la osmosis

tonicity

the ability of a solution to cause a cell to gain or lose water

isotonic solution

solute concentration is the same as that inside the cell; no net water movement across the plasma membrane

hypertonic

solute concentration is greater than that inside the cell; cell loses water

hypotonic solution

solute concentration is less than that inside the cell; cell gains water

osmoregulation

the control of water balance, a necessary adaptation for life

cotransport

occurs when active transport of a solute indirectly drives transport of another solute

exocytosis

transport vesicles migrate to the membrane, fuse with it and release their contents

endocytosis

the cell takes in macromolecules by forming vesicles from the plasma membrane

phagocytosis

a cell engulfs a particle in a vacuole

pinocytosis

molecules are taken up when extracellular fluid is gulped into tiny vesicles

receptor mediated endocytosis

binding of ligands to receptor triggers vesicle formation

ligand

any molecule that binds specifically to a receptor site of another molecule