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AP Biology (Campbell) Chapter 7 Flashcards

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7510725737plasma membranea microscopic membrane of lipids and proteins that form the external boundary of the cytoplasm of a cell or encloses a vacuole and that regulates the passage of molecules in and out of the cytoplasm.0
7510725738selectively permeableA membrane that allows certain molecules or ions to pass through more easily than other, by means of active or passive transport.1
7510725739phospholipidsconsist of a glycerol molecule, two fatty acids, and a phosphate group that is modified by an alcohol. The phosphate group is the negatively-charged polar head, which is hydrophilic. The fatty acid chains are the uncharged, nonpolar tails, which are hydrophobic.2
7510725740lipids and proteinsprimary macromolecules found in membranes3
7510725741fluid mosaic modelThe fluid mosaic model explains various observations regarding the structure of functional cell membranes. In this model, the cell membrane as a two-dimensional liquid that restricts the lateral diffusion of membrane components.4
7510725742transmembrane proteinsthe integral protein completely spans the membrane.5
7510725743integral proteinsproteins that penetrate the hydrophobic interior of the lipid bilayer. C-C chemokine receptor type 5 is such a protein found in white blood cells.6
7510725744peripheral proteinsproteins that are not embedded in the lipid bilayer (Peripheral = of, relating to, or situated on the edge.7
7510725745cell-cell recognitionis one of the ways by which cells communicate with one another. It is possible through specific cellular adhesion molecules on the surface of the cell.8
7510725746transport proteinsproteins that span the plasma membrane and aid in passive or active transport9
7510725747channel proteinstransport proteins that certain molecules or ions use as a tunnel cross the plasma membrane.10
7510725748aquaporinschannel proteins that facilitate the passage of water. The interior Amino Acids are polar and thefore allow a polar channel for the water molecules to pass the nonpolar region of the plasma membrane.11
7510725749carrier proteinstransport proteins that bind to molecules and change shape to shuttle them across the membrane.12
7510725750diffusionthe process by which molecules spread from areas of high concentration to areas of low concentration.13
7510725751concentration gradientis the process of particles, which are sometimes called solutes, moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles. The areas are typically separated by a membrane.14
7510725752passive transporttransport that requires no energy input from the cell (ATP) for transport to occur. Simple diffusion and channel proteins like Aquaporins are examples of passive transport.15
7510725753osmosisa process by which molecules of a solvent tend to pass through a semipermeable membrane from a less concentrated solution into a more concentrated one, thus equalizing the concentrations on each side of the membrane.16
7510725754tonicityThe ability of an extracellular solution to make water move into or out of a cell by osmosis is known as its tonicity. A solution's tonicity is related to its osmolarity, which is the total concentration of all solutes in the solution.17
7510725755isotonicWater enters and leaves the cell at the same rate, so no net change in the osmotic pressere. The cell stays the same.18
7510725756hypertonicwhen the cell is immersed in a hypertonic solution where it loses water to its environment, shrivels and probably dies.19
7510725757hypotonicwhen a cell is immersed in a Hypotonic solution, water enters the cell faster than it leaves, it swells and lyses (explodes) like an overfilled water balloon.20
7510725758osmoregulationthe maintenance of constant osmotic pressure in the fluids of an organism by the control of water and salt concentrations.21
7510725759Paramecium spp.a single-celled organism that lives in pond water. It has a contractile vacuole that pumps out excess water from the organism.22
7510725760turgidwhen the plant cell is very firm, which is a healthy state for most plant cells.23
7510725761flaccidlimp, not firm or strong (If a plant is not watered enough, its leaves become droopy and flaccid.)24
7510725762plasmolysisThis happens when a cell shrinks inside its cell wall while the cell wall remains intact. The plasma membrane pulls away from the wall.25
7510725763facilitated diffusionthe passive movement of molecules down their concentration gradient with the help of transport proteins.26
7510725764ion channels (gated channels)Channels that open or close depending on the presence or abscence of an electrical, chemical, or physical stimulus.27
7510725765active transporttransport that requires the cell to expend metabolic energy and enables a cell to maintain internal concentrations of small molecules. Requires energy.28
7510725766sodium-potassium pumptransport protein that, translocating the bound solute across the membrane. Exchanges sodium ions (Na) for potassium ions (K) across the plasma membrane of animal cells.29
7510725767proton pumpsA proton pump is an integral membrane protein that is capable of moving protons across a biological membrane. Mechanisms are based on conformational changes of the protein structure.30
7510725768exocytosisa process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.31
7510725769endocytosisthe taking in of matter by a living cell by invagination of its membrane to form a vacuole.32
7510725770phagocytosisthe ingestion of bacteria or other material by cells such as amoebas. "Cell Eating"33
7510725771pinocytosisthe ingestion of liquid into a cell by the budding of small vesicles from the cell membrane. "Cell Drinking"34
7510725772receptor-mediated endocytosisis a process by which cells absorb metabolites, hormones, other proteins - and in some cases viruses - (endocytosis) by the inward budding of the plasma membrane vesicles containing proteins with receptor sites specific to the molecules being taken in.35
7510725773lipoproteinsany of a group of soluble proteins that combine with and transport fat or other lipids in the blood plasma. Cholestorol is the kind you hear the most about since high levlse of LDL cholesterol are linked to cardiovascular disease.36

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