Chapter 3: Movement in and Out of the Cell

Comprehensive vocabulary flashcards covering the processes of diffusion, osmosis, and active transport, as well as the effects of solutions on animal and plant cells.

Diffusion

The net movement of particles from a region of their higher concentration to a region of their lower concentration down a concentration gradient as a result of their random movement.

Brownian Motion

The random movement of particles, which increases as their kinetic energy increases.

Partially Permeable Membrane

A membrane that allows only certain molecules to pass through and enter or leave the cell.

Concentration Gradient

The difference in particle concentration between two regions; a greater difference between concentrations increases the rate of diffusion.

Osmosis

The net movement of water molecules from a region of high water potential (low solute concentration) to a region of low water potential (high solute concentration) through a partially permeable membrane.

Shrinkage (Animal Cells in Concentrated Solution)

The reduction in size of animal cells caused by water diffusing out of the cell through the partially permeable cell membrane when placed in a concentrated solution.

Flaccid

The limp state of a plant cell when it loses water by osmosis in a concentrated solution, which causes the plant to wilt.

Plasmolysis

The condition of a plant cell when substantial water diffuses out of the cytoplasm and vacuole into a concentrated solution, causing the cell membrane to pull away from the cell wall.

Turgor Pressure

The internal pressure exerted when the cytoplasm and vacuole become full of water and push the cell membrane outward against the rigid cell wall.

Turgid

The swollen and firm state of a plant cell when water enters by osmosis in a dilute solution; this condition keeps the plant in an upright position.

Cell Bursting (Lysis)

The rupturing of an animal cell that occurs when placed in a dilute solution or pure water because water enters via osmosis and there is no cell wall to withstand the pressure.

Active Transport

The net movement of particles from a region of their lower concentration to a region of their higher concentration against a concentration gradient using energy provided by respiration.

Transport Protein

A membrane protein that binds a specific molecule (such as glucose), changes shape using energy provided by cellular respiration, and pushes the molecule into the cell.