chapter 3 Flashcards
(96 cards)
cell theory
cell is basic structural and function unit of life
plasma membrane
separates intracellular fluids from extracellular fluids
glycocalyx
glycoprotein area abutting the cell that provides highly specific biological markers which cells recognize one another
fluid mosaic model
double bilayer of lipids with imbedded, dispersed proteins
- bilayer consists of phospholipids, cholesterol, and glycolipids
glycolipids
are lipids with attached sugar groups
fluid mosaic model
slide 6
integral proteins
attached with hydrophobic and hydrophilic regions (transmembrane proteins and used for transporting)
peripheral proteins
attached loosely integral proteins that are network of filaments that help support the membrane from the cytoplasmic side
transport membrane porteins
provides a hydrophilic channel across membrane that is selective for a particular solute. some hydrolyze ATP as an energy source to pump
enzymatic activity membrane protein
active site exposed to substances in the adjacent solution. in some cases, several catalyze sequential steps of a metabolic pathway
receptors for signal transduction membrane protein
have a binding site with specific shape for specific thing to bing on. chemical change can occur
intercellular joining membrane proteins
membrane proteins of adjacent cells may be hooked together in various kinds of intercellular junctions. they provide temporary binding sites that guide cell migration and other cell to cell interactions
cell to cell recognition membrane proteins
some glycoproteins serve as identification tags that are specifically recognized by other cells
glycoproteins
proteins bonded to short chains of sugars
attachment to cytoskeleton and extracellular matrix membrane protein
elements of cytoskeleton and extracellular matrix are anchored. fix locations and cell movement
lipid rafts
conc. platforms for cell signaling molecules
3 factors that bind cells together
glycoproteins in the glycocalyx act as an adhesive. wavy contours of the membranes of adjacent cells fit together. special cell juctions
tight junction
impermeable junction that encircles the cell. ( epithelial cells lining GI tract)
desmosome
anchoring junction scattered along the sides of cells (skin and heart muscle)
gap junction
nexus that allows chemical substances to pass between cells (heart and smooth muscle)
diffusion
molecules/ ions move from high to low conc.
simple diffusion
diffusion of molecule or ion will directly through a plasma membrane (lipid soluble and small enough to pass through membrane channels and assisted by a carrier molecule)
facilitated diffusion
assisted diffusion where the substance binds to a carrier protein or passes through a channel (uses kinetic energy) transports glucose, amino acids and ions
osmosis
diffusion of water solvent across a semipermeable membrane