Term | Definition |
Active trasnport | Transport against a concentration gradient that requires chemical energy |
Carrier Protein | involved in the movement of ions, small molecules, or macromolecule, across a biological membrane |
Cell Membrane | the semipermeable membrane surrounding the cytoplasm of a cell. |
channel protein | A protein that allows the transport of specific substances across a cell membrane |
concentration gradient | from higher concentration to lower concentration |
diffusion | the net movement of molecules or atoms from a region of high concentration to a region of low concentration |
endocytosis | a form of active transport in which a cell transports molecules into the cell by engulfing them in an energy-using process. |
exocytosis | a form of active transport in which a cell transports molecules out of the cell by expelling them in an energy-using process |
facilitated transport | A form of passive transport in which materials are moved across the plasma membrane by a transport protein down their concentration gradient |
fluid mosaic membrane model | In this model, a flexible layer made of lipid molecules is interspersed with large protein molecules that act as channels through which other molecules enter and leave the cell. |
glycolipid | lipids with a carbohydrate attached. Their role is to provide energy and also serve as markers for cellular recognition. |
glycoprotein | any of a class of proteins that have carbohydrate groups attached to the polypeptide chain. Also called glycopeptide. |
hydrophilic | having a tendency to mix with, dissolve in, or be wetted by water. |
hydrophobic | tending to repel or fail to mix with water. |
hypertonic | a solution of higher osmotic pressure than another solution with which it is compared |
hypotonic | any solution with a lower osmotic pressure than another solution |
isotonic | a solution having the same osmotic pressure as some other solution |
osmosis | a process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one |
passive transport processes | The movement of particles or ions across a semipermeable membrane without the expenditure of energy. |
phagocytosis | the engulfing of larger, solid particles |
phospholipid | a lipid containing a phosphate group in its molecule |
phospholipid bilayer | a two-layered arrangement of phosphate and lipid molecules that form a cell membrane |
pinocytosis | the ingestion of liquid into a cell by the budding of small vesicles from the cell membrane. |
pressure gradient | from higher pressure to lower pressure |
selectively permeable | a membrane that allows certain molecules or ions to pass through it by means of active or passive transport. |
tonicity | a measure of the amount of substance dissolved in a liquid |