Chapter 8 Vocabulary AP Biology

Active Transport
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Terms in this set (36)
Active Transport
The movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.
Amphipathic Molecule
A molecule that has both a hydrophilic region and a hydrophobic region.
Aquaporin
: Integral membrane proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells.
Concentration gradient
A gradient in concentration of a solute as a function of distance through a solution.
Co transport
: An integral membrane protein that is involved in secondary active transport. It works by binding to two molecules or ions at a time and using the gradient of one solute's concentration to force the other molecule or ion against its gradient.
Diffusion
The passive movement of molecules or particles along a concentration gradient, or from regions of higher to regions of lower concentration.
Electrochemical gradient
A gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts, the electrical potential and a difference in the chemical concentration across a membrane.
Electrogenic pump
An energy-requiring process in which there is a net transfer of charge across the membrane resulting in a membrane voltage.
Endocytosis
The taking in of matter by a living cell by invagination of its membrane to form a vacuole.
Exocytosis
A process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.
Facilitated diffusionPassive transport aided by proteinsFlaccid:weak, lax, and softFluid Mosaic Model: currently accepted model of the cell membrane structure. Membrane is a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.Gated channela trans membrane protein channel that opens and closes in response to a particular stimuli.GlycolipidA lipid with one or more covalently attached carbohydrates.Glycoprotein:A protein with one or more covalently attached carbohydrates.Hypertonic:Referring to a solution that when surrounding a cell, will cause that cell to lose water.Integral proteinA trans membrane protein with hydrophobic regions that extend into the hydrophilic interior of the membrane and hydrophilic regions in contact with the aqueous solutions of the membrane.Ion channel:a trans membrane protein channel that allows a specific ion to diffuse across the membrane and down its concentration or electrochemical gradient.IsotonicThe concentration is the same n the inside as well as the outside. No net movement.LigandA molecule that binds specifically to another molecule, usually a bigger one.Membrane potential:The difference in electrical charge across a cell's plasma membrane due to differential distribution of ions.OsmoregulationRegulation of solute concentrations and water balance by a cell or organismOsmosisThe diffusion of free water across a selectively permeable membrane.Passive transportThe diffusion of a substance across a biological membrane with no expenditure of energy.Peripheral proteinA protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.Phagocytosis:The ingestion of bacteria or other material by phagocytes and ameboid protozoans.PinocytosisA type on endocytosis in which the cell ingests extracellular fluid and its dissolved contents.PlasmolysisIn walled cells where the cytoplasm shrivels up and the plasma membrane pulls away from the cell wall. When a cell loses water to a hypertonic environment.Proton pumpAn active transport protein in a cell membrane that uses ATP to transport hydrogen ions outs of a cell against their concentration gradient.Receptormediated endocytosis: Process by which cells internalize molecules by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being internalized.Selective Permeability: A property of biological membranes that allows them to regulate the passage of substances across them.Sodium-potassium pumpA transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell.TonicityThe ability of a cell to gain or lose water.Transport proteinA trans member protein that helps a certain substance cross the membrane.TurgidSwollen or distended