Hypertonic, Hypotonic, and Isotonic

Front

Cell Membrane Noun

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[sel mem-breyn]

Back

Cell Membrane

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The semipermeable structure that encloses a cell's contents and regulates what substances enter and leave the cell.

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Example: This diagram shows a close-up of the cell membrane, highlighting its structure with a phospholipid bilayer and embedded proteins that control what enters and leaves.

Front

Homeostasis Noun

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[hoh-mee-oh-stey-sis]

Back

Homeostasis

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The process by which a cell maintains a stable internal balance by controlling what substances enter and exit.

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Example: This image uses a balance scale to show that homeostasis is the body's way of keeping internal conditions, like temperature and sugar levels, stable.

Front

Selective Permeability Noun

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[suh-lek-tiv pur-mee-uh-bil-i-tee]

Back

Selective Permeability

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The property of a cell membrane that allows only certain molecules or ions to pass through it.

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Example: This diagram shows a selectively permeable membrane that lets water pass but blocks solutes, causing water to move toward the area with a higher solute concentration.

Front

Passive Transport Noun

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[pas-iv trans-pawrt]

Back

Passive Transport

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The movement of substances across a cell membrane from an area of higher to lower concentration without using energy.

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Example: This diagram shows passive transport, where molecules move from an area of high concentration to low concentration across a cell membrane without using energy.

Front

Concentration Gradient Noun

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[kon-sen-trey-shuhn grey-dee-uhnt]

Back

Concentration Gradient

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The difference in the concentration of a substance across a distance, which drives the movement of molecules during diffusion.

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Example: This image shows a concentration gradient, where particles are more crowded (high concentration) on one side of a barrier and less crowded (low concentration) on the other.

Front

Osmosis Noun

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[oz-moh-sis]

Back

Osmosis

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The passive movement of water molecules across a selectively permeable membrane from a high to a low water concentration area.

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Example: This diagram shows a potato chip in distilled water (hypotonic) and another in salt water (hypertonic), setting up the conditions for osmosis.

Front

Solute Noun

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[sol-yoot]

Back

Solute

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A substance that is dissolved in another substance, known as the solvent, to form a complete solution.

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Example: This diagram shows that a solute (pink particles) is the substance that dissolves in a solvent (blue particles) to form a solution.

Front

Equilibrium Noun

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[ee-kwuh-lib-ree-uhm]

Back

Equilibrium

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The state in which the concentration of a substance is evenly distributed, resulting in no net molecular movement.

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Example: This diagram shows particles moving across a cell membrane until they are evenly spread out on both sides, reaching a balanced state called equilibrium.

Front

Tonicity Noun

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[toh-nis-i-tee]

Back

Tonicity

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The ability of an external solution to cause a cell to gain or lose water, determined by solute concentration.

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Example: This diagram shows how water moves in or out of a plant cell based on the surrounding solution, a process called tonicity, affecting the cell's shape.

Front

Hypotonic Adjective

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[hahy-poh-ton-ik]

Back

Hypotonic

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Describes a solution with a lower solute concentration and higher water concentration compared to another solution, causing cell swelling.

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Example: In a hypotonic solution, there are fewer solute particles outside a cell, causing water (H2O) to move into the cell through osmosis.