AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

AP Biology: Cell Membrane and Transport Flashcards

Terms : Hide Images
5280829480selective permeabilityA property of biological membranes that allows them to regulate the passage of substances across them.0
5280829481amphipathicHaving both a hydrophilic region and a hydrophobic region.1
5280829482fluid mosaic modelThe currently accepted model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.2
5280829483integral proteinsA transmembrane protein with hydrophobic regions that extend into and often completely span the hydrophobic interior of the membrane and with hydrophilic regions in contact with the aqueous solution on one or both sides of the membrane(or lining the channel in the case o a channel protein).3
5280829484peripheral proteinA protein loosely bound to the surface of a membrane or to part of an integral protein and not embedded in the lipid bilayer.4
5280829485glycolipidsA lipid with one or more covalently attached carbohydrates.5
5280829486glycoproteinA protein with one or more covalently attached carbohydrates.6
5280829487transport proteinsA transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane.7
5280829488aquaporinsA channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of free water across the membrane.8
5280829489diffusionThe random thermal motion of particles of liquids, gases, or solids. In the presence of a concentration or electrochemical gradient, diffusion results in the net movement of a substance from a region where it is more concentrated to a region where it is less concentrated.9
5280829490concentration gradientA region along which the density of a chemical substance increases or decreases.10
5280829491passive transportThe diffusion of a substance across a biological membrane with no expenditure of energy.11
5280829492osmosisThe diffusion of free water molecules across a selectively permeable membrane. `12
5280829493tonicityThe ability of a solution surrounding a cell to cause that cell to gain or lose water.13
5280829494isotonicReferring to solution that, when surrounding a cell, causes no net movement of water into or out of the cell.14
5280829495hypertonicreferring to a solution that, when surrounding a cell, will cause the cell to lose water15
5280829496hypotonicreferring to a solution that, when surrounding a cell, will cause the cell to take up water16
5280829497osmoregulationregulation of solute concentrations and water balance by a cell or organism17
5280829498turgidswollen or firm18
5280829499flaccidlimp19
5280829500plasmolysisa phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment20
5280829501facilitated diffusionthe diffusion of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure21
5280829502ion channelsA transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.22
5280829503gated channelA transmembrane protein channel that opens or closes in response to a particular stimulus.23
5280829504active transportThe movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring and expenditure of energy.24
5280829505membrane potentialThe difference in electrical charge(voltage) across a cell's plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.25
5280829506electrochemical gradientThe diffusion gradient of a ion, which is affected by both the concentration difference of an ion across a membrane(a chemical force) and the ion's tendency to move relative to the membrane potential(an electrical force).26
5280829507electrogenic pumpAn active transport protein that generates voltage across a membrane while pumping ions.27
5280829508proton pumpAn active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient generating a membrane potential in the process.28
5280829509cotransportThe coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.29
5280829510exocytosisThe cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane.30
5280829511endocytosisCellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane.31
5280829512phagocytosisA type of endocytosis in which large particulate substances or small organisms are taken up by a cell. It is carried out by some protists and by certain immune cells of animals (in mammals, mainly macrophages, neutrophils, and dendritic cells)32
5280829513pinocytosisA type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes.33
5280829514receptor mediated endocytosisThe movement of specific molecules into a cell by the inward budding of vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.34

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!