what makes up the fluid mosaic model of cellular membranes?
proteins inside the lipid bilayer
what does amphipathic mean?
It means that it has areas that like water and areas that dont like water
what bonds the phospholipid bilayer together
hydrophobic interactions
do cellular membranes become more loose or compact as temperature goes up?
more loose
what’s the difference between peripheral proteins and integral proteins
integral proteins penetrate the hydrophobic interior while peripheral proteins are bounded loosely to the membrane
what’s a transmembrane protein
an integral protein that spans the whole membrane (extracellular side to intracellular side)
what role do carbohydrates play in cells?
they help with cell to cell communication
what role does cholesterol play in the fluid mosaic model?
they are fluidity buffers– they reduce fluidity when it gets too hot and prevents solidification when temps are too low
which secondary protein structure forms as a transmembrane protein in the bilayer?
alpha helix; their hydrophobic side faces the fatty acids and their hydrophilic sides face inwards towards the polar molecules
where are phospholipids assembled
in the ER
what cell structures are in ALL cells
cytosol, chromosomes, and ribosomes
what makes the eukaryote different from prokaryote?
it has a double membrane bounded nucleus
prokaryotes don’t have nucleuses but they’re chromosomes are centered in an area called
nucleoids
what does selective permeability mean?
it means that the bilayer allows some substances to cross more easier than others?
what is easily transported in a phospholipid bilayer
small non-polar molecules such as O2 or CO2, CH4
aquaporins ?
channel proteins that facilitate water transport (has 4 identical polypeptide subunits)
what does a carrier protein do?
it holds onto the solute and changes shape to get them across the membrane (alternate between two shapes)
what does passive transport mean?
it means that no energy was invested; going down the concentration gradient
osmosis
the movement of water across selectively permeable membrane
hypotonic
water is going into the cell (outside solute is less than inside)
hypertonic
water is going out (outside solute is more than inside)
when is facilitated diffusion needed?
when polar/ionized molecules diffuse passively through transport proteins
what is active transport?
when the molecule is going against the concentration gradient; energy is invested
in a sodium potassium pump how many molecules are going in and going out
3 sodium atoms are going out and 2 potassium atoms are going in
