cell membranes part 1 Flashcards
what do membranes surround
eukaryotic and prokaryotic cell and the organelles of eukaryotic cells
what do cell membranes regulate
traffic of molecules in and out of cells and in and out of organelles
what is the main lipid composing cell membranes
phospholipids
how are the amphipathic phospholipids making up cell membranes arranged
in a bilayer
what do cell membranes also contain
-cholesterol
-proteins
-sugars
where can proteins be found on on cell membranes
in and on the membranes
where can you find sugars on cell membranes
-what can they only be attached to
-what do they help cells do
-which way do they face
on outer face
-can be attached to proteins and lipids (glycoproteins and glycolipids)
-help cells recognize each other
-only face outward, away from cell center
what are some things membrane proteins assist witth
-transport
-enzymatic activity
-signal transduction
-cell-cell recognition
-intercellular joining
-attachment to the cytoskeleton and extracellular matrix
where are integral proteins and what are many of them
they are embedded in the membrane, many are transmembrane proteins that completely cross through the membrane
what do peripheral proteins associate with
membrane surface
what are glycoproteins
proteins that are attached with sugar molecules
what can peripheral and integral proteins be
glycoproteins
many integral proteins have one or more _ _____ in their transmembrane region
alpha helices
why do many integral proteins have one or more alpha helices in their transmembrane region
because the non polar side chains on an alpha helix easily interact with the hydrophobic fatty acid rails of the phospholipids
what can multiple alpha helices form? what does it allow
can form hydrophilic channel to allow a polar molecule to cross the membrane
