| A | B |
|---|
| active transport | the movement of ions or molecules across a cellular membrane from a lower to a higher concentration, requiring the consumption of energy |
| adhesion junction | the junction between cells in which the adjacent plasma membrances do not touch but are held by intercellular filaments attached to buttonlike thickenings |
| carrier protein | a protein that transports a specific substance or group of substances across the cell membrane |
| cell recognition protein | a glycoprotein that helps the body defend itself against pathogens |
| cell wall | the structure that surrounds a plant, protistan, fungal, or bacterial cell and maintains cell's shape and rigidity |
| channel protein | protein that forms a channel to allow a particular molecule or ion to cross the plasm membrane |
| cholesterol | one of the major lipids found in animal plasma membranes which helps maintain stability |
| concentration gradient | gradual change in chemical concentration from one point to another |
| crenation | shriveling of an animal cell due ot water leaving the cell when the environment is hypertonic |
| differentially permeable | ability of the plasma membrane to regulate the passage of substances into and out of the cell, allowing some to pass through and not others |
| diffusion | movement of molecules or ions from a region of higher to lower concentration |
| endocytosis | process by which substances are moved into the cell from the environment by phagocytosis or pinocytosis |
| enzymatic protein | protein that catalyzes a specific reaction |
| exocytosis | process in which an intercellular vesicle fuses with plasma membrane so that the vesicle's contents are released outside the cell |
| facilitated transport | the passive transfer of a substance into or out of teh cell along a concentration gradient by a process that requires a carrier |
| fluid mosaic model | model for plasma membrane based on the changing location and pattern of protein molecules in a fluid phospholipid bilayer |
| gap junction | junction between cells formed by the joining of two adjacent plasma membranes that lends strenth and allows ions, sugars, and small molecules to pass between cells |
| glycolipid | a lipid in plasma membranes that bears a carbohydrate chain attached to a hydrophobic tail |
| glycoprotein | protein in plasma membrane that bears a carbohydrate chain |
| hypertonic solution | solution with a higher solute concentration that the cytoplasm of the cell |
| hypotonic solution | a lower solute concentration than the cytoplasm of a cell; causes a cell to swell |
| isotonic solution | a solution that is equal in solute concentration to that of the cytoplasm of a cell |
| osmosis | diffusion of water through a differentially permeable membrane |
| osmotic pressure | measure of the tendency of water to move across a differentially permeable membrane |
| phagocytosis | process by which amoeboid-type cells engulf large substances, forming an intracellular vacuole |
| phospholipid bilayer | the major component of the plasma membrane |
| pinocytosis | process by which vesicle formation brings macromolecules into the cell |
| plasmodesmata | cytoplasmic strands that extend through pores in the cell wall and connect the cytoplasm of two adjacent cells |
| plasmolysis | contraction of cell contents due to loss of water in plant cells |
| receptor-mediated endocytosis | selective uptake of molecules into a cell by vacuole formation after they bind to a specific receptor proteins in the plasma membrane |
| receptor protein | protein located in plasma membreane that binds to a substance that alters some metabolic aspect of the cell |
| sodium-potassium pump | a carrier protein that moves sodium ions out of and potassium ions into animal cells; important in nerve and muscle cells |
| solute | the substance that is dissolved in a solvent, forming a solution |
| solution | fluid that contains a dissolved solid |
| solvent | the liquid portion of a solution that serves to dissolve a solute |
| tight junction | junction between cells when adjacent plasma membrane proteins join to form an impermeable barrier |
| tonicity | osmolarity of a solution compared to that of a cell |
| turgor pressure | the pressure of the cell contents against the cell wall determined by the water content of the vacuole and providing internal support |
