Biology Key Terms Quiz

Study Notes

Diffusion: Movement of molecules from an area of higher concentration to an area of lower concentration.
Active Transport: Movement of molecules from an area of low concentration to an area of high concentration, requiring energy.
Osmosis: Movement of water molecules across a selectively-permeable membrane from a region of high concentration to a region of low concentration.
Selectively Permeable Membrane: A barrier that allows some substances to pass while blocking others.

Isotonic Solution: Has the same concentration as the cytoplasm of the cell, resulting in no net movement of water.
Hypotonic Solution: Has a lower concentration than the cytoplasm, potentially causing cells to swell.
Hypertonic Solution: Has a higher concentration than the cytoplasm, which can lead to cell shrinkage.

Turgor Pressure: The pressure exerted by the cytoplasm and vacuole against the cell wall, providing structural support to the cell.
Function of Turgor Pressure: Essential for maintaining cell shape and rigidity.
Plasmolysis: Occurs when the cell membrane pulls away from the cell wall due to loss of water, usually in a hypertonic environment.

Osmosis in Food Preservation: Salt solutions are often used to preserve fish and meat by drawing out moisture through osmosis.

Selectively Permeable Material: Visking tubing is commonly used in experiments to simulate a selectively permeable membrane.
Preventing Leakage: Tied ends of visking tubing are kept above water to prevent any leakage of the solution inside.
Observation of Osmosis: The increase in mass and fullness of visking tubing filled with sucrose solution indicates that osmosis has taken place.