Osmosis & Diffusion Lab 1 Terms

Simple rules and definition

Plasma Membrane

Made up of a phospholipid bilayer, with polar heads (hydrophilic) and nonpolar tails (hydrophobic). Making it selectively permeable, water and small non-charged particles can pass both ways.

Plasma Membrane: Proteins

Proteins embedded in the membrane facilitate passage of other materials, polar molecules and ions.

Passive Transport

Required no ATP; Simple Diffusion: Facilitated Diffusion with Carrier and Channel Proteins; Goes with the high to low gradient.

Active Transport

Utilizes ATP to move substances against the concentration gradient

Solute

Molecule that is dissolves or broken down into smaller molecules or ions

Solvent

The liquid the solute is dissolved in

Diffusion

The natural movement of solute down the concentration gradient, high to low. Passive and continues until equailibrium is achieved

Factors that affect the rate of diffusion

Faster rate…
smaller Molecular weight

higher concentration gradient
higher temperature

more membrane surface area

higher permeability (thinner membrane)

Rate of Diffusion

The more solute leads to a higher rate of diffusion. However, regardless of amount of solute the rate starts decreasing with time.

Osmosis

Diffusion of water across a selectively permeable membrane (in osmosis, only water can travel through the membrane, and the solute cannot due to the membrane).
Water moves from a low solute concentration (high water concentration) to an area of high solute concentration (low water concentration)

Hypotonic

A solution with lower solute
Water rushes into cell causing it to swell and possibly lyse

Lyse

Cell burst

Isotonic

A solution had the equal concentration of solute to the cell
Cell will neither gain or lose water

Hypertonic

A solution with a higher concentration of solute
Water leaves the cell, causing it to shrivel or crenate

Crenate

Shrink

Tonicity

The comparison of relative concentration of two solutions, seperated by a selectively permeable membrane.

If the solution becomes opque after adding blood cells you can assume

The cell is either in an isotonic or hypertonic (crenated) state

If the solution becomes trandparent after adding blood cells you can assume

The cells were in an hypotonic state and bursted (lysed)

Facilitated diffusion is used to transport

Sugars and animo acids