Chapter 4 - Membranes and Transport Flashcards
What are artificial membranes
simple mixtures of amphipathic lipid molecules that form structures to minimize potential energy
what are the parts of a amphipathic molecule
polar at one end (try to interact with water) and non polar at the other (try not to interact with water)
Where are the intrinsic proteins or transmembrane proteins embedded
lipid bilayer
extrinsic proteins are
loosely associated with the membrane (can be attached to transmembrane proteins or with the lipids on one side
a membrane with lots of saturated fatty acids
intact at higher temperatures and solid at low temperatures
a membrane with lots of unsaturated fatty acids
fluid at lower temperatures and not able to function at higher temperatures
Carbon double bonds induce “kinks” in fatty acid tails and
reduce surface area for interactions
cholesterol disrupts
hydrophobic interactions in fatty acid tails
transmembrane proteins aid in transport of
ions and polar molecules and signal communication
what molecules can cross the phospholipid bilayer
non-polar and small uncharged polar
what molecules cannot cross the phospholipid bilayer
large uncharged polar molecules and ions
diffusion
high to low concentration
osmosis
low concentration of solute to high concentration of solute
water is ______ and cannot easily cross cell membrane
polar
what is needed for water to cross membrane
aquaporin
facilitated diffusion requires ______ to get molecules across membrane
proteins
channel proteins form ______
openings in plasma membrane
carrier proteins take molecules from
one side to the other
hypotonic moves _____ cell
into
hypertonic moves ______ cell
out of
Symporters bind 2 solutes and moves them across the membrane in the ____ direction
same
antiporters bind 2 solutes and move them in the ______ direction across the membrane
opposite
Symporters and anti ports are often used for ______ transport
active
active transport moves solutes from _____ to ______ concentrations using ATP as energy source
low to high
primary active transport moves solute using ___ as energy source
ATP
Secondary Active transport uses energy available due to a _______, favourable concentration gradient
second
