Water Balance and Membrane Physiology in Cells

Osmosis

Water movement across a semi-permeable membrane.

Osmolality

Osmoles per kilogram of fluid.

Osmolarity

Osmoles per liter of fluid.

Molarity

Moles of solute per liter of solution.

Concentration Gradient

Difference in solute concentration across a membrane.

Diffusion

Molecules moving from high to low concentration.

Osmotic Pressure

Force needed to equalize solute concentration.

Net Movement of Water

Water movement changes cell shape and volume.

Isotonic Environment

Equal solute concentration inside and outside cell.

Valence

Charge of an ion affecting its reactivity.

Primary Active Transport

Energy-dependent movement against concentration gradients.

Facilitated Diffusion

Transport requiring a carrier protein, no ATP.

Simple Diffusion

Lipid-soluble molecules pass through the membrane.

Sodium-Potassium Pump

Maintains Na and K concentration gradients using ATP.

Electrochemical Gradient

Combined concentration and electrical gradients across membranes.

Carrier Membrane Proteins

Control transport of nutrients and ions.

Cell Differentiation

Specialization of cells based on structure.

Membrane Fluidity

Phospholipid composition affects membrane flexibility.

Heat Tolerance in Camelids

Can lose 25% body water without harm.

Sodium-Glucose Co-Transporter

Uses sodium gradient to absorb glucose.

Concentration of Ions

Varies inside and outside the cell.

Homeostatic Mechanisms

Regulate isotonic environments in the body.