Biology - Movement across membranes

Diffusion

the net movement of molecules from a region of their higher concentration to a region of their lower concentration, down a concentration gradient, due to their random motion

Osmosis

the diffusion of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane

Active transport

movement of molecules in our out of a cell through the cell membrane from a region of their lower concentration to a region of their higher concentration, against a concentration gradient, using energy released during respiration

Hypotonic solution

dilute solution such as water

Hypertonic solution

concentrated solution such as sugar/salt solution

Isotonic solution

same solute concentration and water concentration so no net movement of water

Cell lysis

When a animal cell gains water and starts to expand and eventually bursts

Crenated

When a animal cell loses water and start to shrivel up

Flaccid

When a plant cell loses water pressure

Plasmolysed

When a flaccid plant cell’s cell membrane and cytoplasm pull away from the cell wall due to the loss of water

Turgid

When a plant cell gains water and cell membrane lies next to the cell wall

Equilibrium

Point at which the graph line hits 0; water is entering and leaving the cell evenly

Turgor pressure

water pressure inside plant cells

ATP

energy-storing molecule