Cell Transport Mechanisms: Passive and Active Transport

Cell Membrane

Boundary regulating material movement in cells.

Passive Transport

Movement across membrane without cellular energy.

Diffusion

Movement from high to low concentration.

Equilibrium

Equal concentration on both sides of membrane.

Facilitated Diffusion

Transport through protein channels without energy.

Aquaporins

Water channel proteins facilitating osmosis.

Osmosis

Diffusion of water through selectively permeable membrane.

Isotonic Solution

Equal concentration of solutes on both sides.

Hypertonic Solution

Higher concentration of solutes outside the cell.

Hypotonic Solution

Lower concentration of solutes outside the cell.

Osmotic Pressure

Force exerted by water movement in cells.

Active Transport

Movement against concentration gradient requiring energy.

Transport Proteins

Proteins that move ions across cell membranes.

Endocytosis

Process of taking material into the cell.

Exocytosis

Release of materials from the cell.

Phagocytosis

Engulfing particles using extensions of cytoplasm.

Pinocytosis

Taking up liquid by forming tiny pockets.

Bulk Transport

Transport of large molecules via membrane movements.

Molecular Transport

Transport of small molecules by protein pumps.

Cytoplasm

Liquid environment containing dissolved substances.

Concentration Gradient

Difference in concentration across a membrane.

Cell Swelling

Caused by water influx in hypotonic solutions.

Cell Shrinking

Caused by water loss in hypertonic solutions.

Vesicle

Small membrane-bound sac within the cytoplasm.

Vacuole

Storage sac within a cell, often for water.

Lipid Bilayer

Double layer of phospholipids forming cell membrane.

Hydrophobic

Water-repelling characteristic of lipid bilayer.

Solute

Substance dissolved in a solution.

Solvent

Liquid in which solutes are dissolved.