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metabolism
process of the body converting food and energy into vital functions
phospholipids
bilayer, polar heads facing each other (hydrophilic) and nonpolar tails facing each other (hydrophobic)
marker molecules
glycoproteins or glycolipids
allow cells to identify one another or other molecules, intercellular communication
specificity
based on shape, single types of molecules
voltage gated ion channels
open when there is a change in charge across plasma membrane
functions of plasma membrane
separates cytoplasmic substances from extracellular environment, encloses and supports cell contents, attaches to extracellular environment or to other cells, ability to recognize and communicate w other cells, determines what moves in and out of cells
cholesterol
provides stability to the membrane
transport proteins
involve carrier proteins or channels in cell membrane
specificity, competition, saturation
competition
among molecules of similar shape
uniporters
move one membrane
nucleus
directs cell activities
integral membrane proteins
extend into membrane, can form channels through membrane
channel proteins
integral membrane proteins that form channels through membrane, determines what can move through, hydrophobic regions and hydrophilic regions
saturation
rate of transport limited to number of available carrier proteins
symporters
moves two ions/molecules in same direction at same time
cytoplasm
contains organelles that perform specific functions
peripheral membrane proteins
attach to integral proteins, functions depend on shape and chemical characteristics
carrier proteins/transporters
integral proteins that move ions from one side of membrane to another
leak ion channels
always open
antiporters
moves 2 ions/molecules in opposite directions at same time
characteristics of a cell
metabolism and energy use, synthesis, communication, reproduction and inheritance
receptor proteins
proteins/glycoproteins in membranes w an exposed receptor site on outer cell surface, can attach to specific chemical signal molecules and act as intercellular communication systems, ligand can attach only to cells with that specific receptor
ATP powered pumps
requires ATP, have binding sites for specific ions/molecules and ATP
ligand gated ion channels
open or closed by certain stimuli
receptors linked to channel proteins
attachment to receptor-specific chemical signals (acetylcholine) to receptors cause changes in the shape of chemical protein
some toxins disrupt normal cell activity by blocking acetylcholine bonding sites