diffusion osmosis and enzymes

competitive inhibition

a substrate molecule is prevented from binding to the active site of an enzyme by a molecule that is very similar in structure to the substrate

noncompetitive inhibition

a specific type of enzyme inhibition characterized by an inhibitor binding to an allosteric site resulting in decreased efficacy of the enzyme

solvent

the dissolving agent

solute

the dissolved substance

selectively permeable

allowing water to freely pass through but regulating the movement of solutes

diffusion

physical process where molecules move from an area where they are in a high concentration to one where their concentration is lower. energy driving diffusion is intrinsic kinetic energy

osmosis

type of diffusion. its the diffusion of water through a selectively permeable membrane from a region where it is highly concentrated to where its concentration is lower

osmolarity

solute concentration expressed as molarity

hypertonic

solution with a greater concentration

hypotonic

solution with a lower concentration compared to another solution

isotonic

where solute concentrations are equal

tonicity

relative concentration of solutions inside and outside a cell that will determine the direction of water flow

brownian movement

the erratic random movement of microscopic particles in a fluid, as a result of continuous bombardment from molecules of the surrounding medium.

dialysis tubing

is a membrane made of regenerated cellulose fibers formed into a flat tube

osmotic activity in cells

all organisms must maintain an optimum internal osmotic environment. exchange of waste and nutrients between blood and tissues depends on the maintenance of this condition

lysis

the cells swell and the membranes burst

crenate

the cell shrivels and appear bumpy

plasmolysis

when plant cell is placed in a hypertonic solution, water moves out of the cell: the protoplast shrinks and may pull away from the cell wall

protoplast

the plant cell exclusive of the cell wall - the cytoplams enclosed by plasma membrane

turgid

swollen and distended or congested.

tugor pressure

presuure of the protoplast on the cell wall owing to uptake of water

water potential

combined force created by solute concentration and physical pressure