ch. 5 structure and function of plasma membranes Flashcards
what is the fluid mosaic model?
membranes consist of a bilateral of phospholipids in which globular proteins are inserted
what is a glycoprotein?
a protein with carbohydrate attached
what are the four components of cell membranes?
phospholipid bilayer, transmembrane proteins, interior protein network, cell surface markers
what holds together the two layers of the phospholipid bilayer?
hydrogen bonds
what can move through the cell membrane?
individual phospholipids and unanchored proteins
what makes the cell membrane less fluid?
saturated fatty acids
what temps can make the cell membrane more fluid?
warm
what are peripheral membrane proteins?
anchored to a phospholipid in one layer of the cell membrane; possess non-polar domains that are inserted in the lipid bilayer; can move through one layer of the bilayer
what are integral membrane proteins?
proteins that span the lipid bilayer (transmembrane proteins), they have polar domains embedded in the hydrophobic regions of the lipid bilayer, polar domains protrude from both sides of the bilayer
what do all integral proteins possess at least one of?
a transmembrane domain
what is a transmembrane domain?
region of the protein containing hydrophobic amino acids (spans the lipid bilayer)
what can form a b-barrel?
b-sheets
what is a b-barrel?
polar interior, allows water and other small polar molecules to pass through the membrane
what do carrier proteins do?
bind to a specific molecule to facilitate its passage
what molecules do channel proteins let through?
polar molecules
what does hypertonic mean?
it has a high concentration of dissolved molecules
what does isotonic mean?
same
what does active transport need to happed?
energy and carrier proteins
what are uniporters?
carrier proteins that move one molecule at a time
what are symporters?
carrier proteins that move two molecules in the same direction
what are antiporters?
carrier proteins that move two molecules in opposite directions
what is the sodium potassium pump?
an active transport mechanism that uses an antiporter to move three Na+ out of the cell and two K+ into the cell
what is the sodium potassium pump used for?
to depolarize the neurons in the nervous system
what is coupled transport?
uses the potential energy released by diffusion to actively transport a different molecule (uses a symporter)
