Lab 5: Osmolarity

Plasma Membrane

The protective barrier surrounding the contents of a cell, composed of a phospholipid bilayer that regulates the entry and exit of substances.

Osmosis

The movement of water molecules through a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Aquaporins

Specialized protein channels embedded in the plasma membrane that facilitate the rapid transport of water molecules.

Tonicity

The term that describes the osmotic pressure gradient of two solutions separated by a semipermeable membrane.

Isotonic

A solution that has the same solute concentration as another solution, resulting in no net movement of water across the membrane.

Hypotonic

A solution with a lower solute concentration than another solution, leading to water moving into cells, potentially causing them to swell and burst.

Hypertonic

A solution with a higher solute concentration than another solution, causing water to move out of cells, leading to cell shrinkage.

Osmolality

The measure of solute concentration in a solution, expressed as osmoles of solute per kilogram of solvent.

Osmoregulation

The biological process whereby an organism maintains optimal water and solute concentrations within its internal environment.

Osmoregulators

Organisms that actively regulate their internal osmotic environment, maintaining a stable internal pressure regardless of external conditions.

Osmoconformers

Organisms that allow their internal osmotic pressure to match that of their surrounding environment.

Metanephridia

A type of excretory structure found in certain invertebrates that plays a role in osmoregulation and the expulsion of metabolic waste.

Hemolysis

The process in which red blood cells burst due to the influx of water in a hypotonic environment.

Crenation

The shriveling or shrinkage of a cell that occurs when it is placed in a hypertonic solution.