Membrane Structure & Function (Chap 5)
|Plasma Membrane|| Phospholipid bilayer that contains proteins.|
-has numerous functions, including regulating the passage of molecules into and out of the cell.
|Cholesterol|| lipid found in the animal plasma membrane. |
helps modify the fluidity of the membrane. , Provides strength & structural support to membrane in Lipid Bilayer
|Extracellular Matrix|| -Found only in animal cells|
-various functions including lending support to the plasma membrane and assisting communication between cells.
-Meshwork of proteins and polysaccharides in close association with the cell that produced them.
|Carbohydrate Chains||(sugars) on surface are attached to proteins and lipids in the membrane (glycoproteins, glycolipids); many function as cell identification tags|
|Glycocalyx|| "sugar coat" of membrane.|
-protects the cell
-facilitates adhesion between cels, reception of signaling molecules and cell-to-cell recognition.
|Channel Proteins||The proteins involved in the passage of molecules through the membrane. They include a passage that allows a substance to simply move across the membrane.|
|Carrier Proteins||Proteins involved in Selectively interacting with a specific molecule or ion so that it can cross the membrane.|
|Cell Recognition Proteins|| -Glycoproteins. |
-Proteins involved with recognition.
|Receptor Proteins||Proteins that have a shape that allow a specific molecule to bind in it.|
|Enzymatic Proteins|| A protein that catalyzes a specific chemical reaction.|
-Carries out metabolic reactions directly.
|Junction Proteins|| -allow 2 different cells to bond to eachother|
-involved in forming various types of junction between animal cells
-signaling molecules that pass through gap junctions allow the cilia of cells that line your repiratory tract to beat in unison
|Differentially Permeable||Meaning Certain substances can move across the membrane while others cannot.|
|Concentration Gradient||Represents a higher concentration of molecules in one area vs a lower concentration of molecules in another.|
|Aquaporin||Membrane channel protein that allows water to passively move through.|
|Bulk Transport||The process by which large particles and macromolecules are transported through plasma membranes. Inc. exocytosis and endocytosis|
|Osmosis||Diffusion of water across a differentially permeable membrane due to concentration differences.|
|Isotonic Solution||Solution used in labs where cells are normally placed in solution where Solute concentration and water concentration both inside and outside the cell are equal.|
|Tonicity||Strength of the solution.|
|Hypotonic Solution|| Solution that causes cells to swell due to intake of water. |
-Higher Concentration of water then what's inside the cell.
-Net movement from outside to inside.
|Hypertonic Solution|| Solution that may cause cells to shrink or shrivel. |
-Solution with higher percentage of solute (lower co concentration of water) then the cell.
-Net movement from inside to outside, water leaves the cell.
|Turgor Pressure|| the pressure that is exerted on the inside of cell walls and that is caused by the movement of water into the cell.|
-Very important to plant cells to maintain strength.
|Plasmolysis||Shrinking of cell's cytoplasm due to osmosis.|
|Facilitated Transport||is the movement of a molecule from an area of high concentration to an area of lower concentration (diffusion), with the aid of a protein channel or carrier.|
|Active Transport||energy-requiring process that moves material across a cell membrane against a concentration difference|
|Pumps||A name given to Proteins involved in active transport.|
|Exocytosis|| process of exporting proteins from a cell by a vesicle fusing with the plasma membrane and spilling the proteins outside the cell|
(contents leave cell)
|Endocytosis|| Process of cells taking in substances by vesicle formation. A portion of the plasma membrane invaginates to envelop the substances, and then the membrane pinches off to form an intracellular membrane.|
(cell takes in contents)
|Phagocytosis|| - processes of Endocytosis |
process in which extensions of cytoplasm surround and engulf large particles and take them into the cell
|Pinocytosis|| -Process of Endocytosis|
-Process in which vesicles form around a liquid or around very small particles.
|Receptor-Mediated Endocytosis|| -Form of Pinocytosis |
Quite specific, uses a receptor protein shaped in such a way that a specific molecule such as a vitamin, peptide hormone, or lipoprotein can bind to it.
-Far more selective then Pinocytosis.
-Involved in uptake and transfer and exchange of substances between cells.
|Adhesion Junction|| Serve to mechanically attach adjacent cells. |
Internal Cytoplasmic Plaques
-attached to cytoskeleton within each cell
|Desmosomes|| -Type of Adhesion Junction |
-Internal Cytoplasmic plaques, firmly attached to cytoskeleton within each cell, are joined by intercellular filaments
-Results in sturdy, flexible sheets of cells.
-Stretchable tissues of cells held together by These.
|Tight Junction|| -Plasma membrane proteins attach to each other, producing a zipperlike fastening. |
-Between Adjacent cells
|Gap Junction|| Junction in which Allows cells to communicate. |
-Formed when two identical plasma membrane channels join.
-Channel of each cell is lined by six plasma membrane proteins
-Permits small molecules and ions to pass between them.
|Plasmodesmata|| Connects the cytoplasm of living plant cells.|
numerous, narrow, membrane-lined channels that pass through the cell wall.