Cell Membrane Transport

Vocabulary flashcards for cell membrane transport, covering passive, active, and bulk transport, as well as diffusion and osmosis.

Passive Transport

Movement from high to low concentration; no energy required; driven by concentration gradients.

Active Transport

Movement from low to high concentration; requires energy (ATP); enables uptake against gradients.

Bulk Transport

Movement independent of concentration gradients; requires energy; includes processes like endocytosis and exocytosis.

Passive Transport Characteristics

Movement from high to low concentration along the concentration gradient; no energy required; occurs until equilibrium is reached.

Simple Diffusion

Occurs without help from proteins; molecules move freely through the phospholipid bilayer; limited to small, nonpolar molecules.

Facilitated Diffusion

Involves specific membrane proteins; allows transport of molecules that cannot pass readily through the lipid bilayer.

Active Transport Definition

Movement of molecules against their concentration gradient (low to high concentration).

Active Transport Key Characteristics

Energy input is necessary; involves specific transport proteins in the membrane; maintains essential concentration gradients in the cell.

Reverse Osmosis

A semipermeable membrane separates salty/polluted water from pure water; pressure is applied to the salty side to force water the other way. Pure water passes through the membrane and impurities are left behind.

Reverse Osmosis Applications

Desalination of seawater or brine to remove various impurities.

Primary Active Transport

Directly uses ATP to move substances against their concentration gradient; an example is the sodium-potassium pump.

Secondary Active Transport

Uses the electrochemical gradient created by primary active transport to move other substances; does not directly use ATP.

Endocytosis

Cellular process where substances are brought into the cell; includes phagocytosis (cell eating) and pinocytosis (cell drinking); requires energy.

Exocytosis

Cellular process where substances are exported out of the cell; involves vesicles fusing with the plasma membrane; requires energy.

Sodium-Potassium Pump

An example of primary active transport; uses ATP to pump sodium ions out of the cell and potassium ions into the cell, both against their concentration gradients.

Gradient Types

Concentration gradients involve differences in solute concentrations; electrochemical gradients involve both concentration and electrical potential differences.