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| A circular flow of cytoplasm, involving myosin and actin filaments, that speeds the distribution of materials within cells. |
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| Open channels in the cell wall of plants through which strands of cytosol connect from adjacent cells. |
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| Types of intercellular junction in animal cells that prevent the leakage of material between cells. |
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| Types of intercellular junction in animal cells that allow the passage of material or current between cells. |
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| Types of intercellular junction in animal cells that function as an anchor. |
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| A property of biological membranes that allows some substances to cross more easily than others. |
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| Typically transmembrane proteins with hydrophobic regions that completely span the hydrophobic interior of the membrane. |
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| Protein appendages loosely bound to the surface of the membrane and not embedded in the lipid bilayer. |
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| The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area. |
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| An increase or decrease in the density of a chemical substance in an area. Cells often maintain this across their membranes. |
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| The diffusion of a substance across a biological membrane. |
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| In comparing two solutions, referring to the one with a greater solute concentration. |
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| In comparing two solutions, referring to the one with a smaller solute concentration. |
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| Having the same solute concentration as another solution. |
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| The control of water balance in organisms living in hypertonic, hypotonic, or terrestrial environments. |
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| Firm. Walle cells become this as a result of the entry of water from a hypotonic environment. |
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| Limp. Walle cells become this in isotonic surroundings, where there is no tendency for water to enter. |
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| A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall when the cell loses water to a hypertonic environment. |
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| A protein channel in a cell membrane that opens or closes in response to a particular stimulus. |
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| The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins. |
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| A special transport protein in the plasma membrane of animal cells that transports sodium out of the cell and potassium into the cell against their concentration gradients. |
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| The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane. |
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| The cellular uptake of macromelecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle. |
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| A type of endocytosis involving large, particulate substances. |
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| A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. |
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| A hypothesis about the origin of the eukaryotic cell, maintaining that the forerunners of eukaryotic cells were symbiotic associations of prokaryotic cells living inside larger prokaryotes. |
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| A type of cell with a membrane-enclose nucleus and membrane-enclosed organelles, present in protists, plants, fungi, and animals. |
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| A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles; found only in the domains Bacteria and Archaea. |
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| The contraction of a cell after exposure to a hypertonic solution, due to the loss of water through osmosis. |
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