membrane proteins Flashcards
membrane proteins are half of what?
plasma membrane by weight
where do membrane proteins float and move?
in fluid bilayer
what do membrane proteins perform?
most of membrane’s functions
what are the 2 structural types of membrane proteins?
integral and peripheral
integral proteins
embedded within,
extends across, phospholipid bilayer
(integral proteins) hydrophobic regions interact with what interior?
hydrophobic interior
(integral proteins) hydrophilic regions are exposed to what type of environments on what side of membrane?
aqueous environments on either side of membrane
(integral proteins) many integral proteins are what with carbohydrate portion?
many are glycoproteins with carbohydrate portion
are peripheral proteins embedded in lipid bilayer?
peripheral proteins are not embedded in lipid bilayer
peripheral proteins are loosely attached to …….. or …….. surfaces of membrane
exterior or interior surfaces of membrane
what are the functional categories of proteins?
- transport proteins
- cell surface receptors
- identity markers
- enzymes
- anchoring sites
- cell-adhesion proteins
transport proteins
what do transport proteins regulate? give examples
regulate movement of substances across membrane
e.g., channels, carriers, and pumps, symporters, antiporters
cell surface receptors
what do cell surface receptors bind?
bind molecules called ligands
e.g., neurotransmitters released from a nerve cell that binds to a muscle cell to initiate contraction
identity markers
what do identity markers communicate? what are the markers used to distinguish?
they communicate to other cells that they belong to the body
markers are used to distinguish healthy cells from cells to be destroyed
enzymes
what may enzymes be attached to? what do enzymes catalyze?
may be attached to either internal or external surface of a cell
enzymes catalyze chemical reactions
