Ch 4 Cell Theory and Organelles Flashcards
what makes a cell a cell?
barrier, organelles, energy transfer, proteins, DNA
plasma membrane
fluid mixture of equal parts lipid and protein by weight. regulates movement of MOST substances in and out of cell, contains phospholipids, cholesterols, and glycoproteins
phospholipid bilayer
polar hydrophilic heads, nonpolar hydrophobic tails, ensures cytosol remains inside cell and interstitium outside
membrane cholesterol
support
membrane glycoproteins
maintain extracellular matrix
membrane proteins
half of plasma membrane by weight, float and move in fluid bilayer, perform most membrane functions
what are the six membrane proteins
transport, cell surface receptors, identify markers, enzymes, anchoring sites, cell adhesion
transport proteins
regulate movement of substances across membrane
cell surface receptors
bind molecules call ligands
identify markers
distinguish healthy cells from cells to be destroyed
enzymes
catabolize chemical reactions, could be internal or external
anchoring sites
secure cytoskeleton to plasma membrane
cell adhesion
perform cell to cell attachments
ligands
molecules that bind to macromolecules, ie a neurotransmitter released from a nerve cell that binds to the cell surface receptor of a muscle cell
a cell is only a cell if…
…plasma membrane is intact and functioning