Transport across membrane Flashcards
phospholipid bilayer
2 layers of phospholipid that make up the cell membrane
fluid mosaic model
fluid means the phospholipid can move around freely without breaking
mosaic means the proteins are scattered amongst the phospholipids
cholesterol
a lipid steroid embedded in between the fatty acid tails of the phospholipid bilayer
regulates the fluidity of the membrane
carbohydrates
in chains and extend outside the cell, rooted in membrane to lipid or protein
aids with cell to cell communication
simple diffusion
the passive movement of molecules from areas of high concentration to areas of low concentration (down the concentration gradient)
moves non polar, hydrophobic small molecules (oxygen, carbon dioxide)
facilitated diffusion
movement of a substance across a membrane with the help of a protein channel
moves polar, hydrophilic, large molecules (ions, glucose)
osmosis
movement of water molecules from a region of high concentration to a region where concentration is low, through a selectively permeable membrane
active transport
movement of molecules across a semipermeable membrane that requires energy
exocytosis
a type of bulk transport that moves large substances out of the cell
endocytosis
a type of bulk transport that moves large substances into the cell
bulk transport
the movement of groups of molecules across the plasma membrane
phagocytosis
endocytosis of solid
material or food particles
pinocytosis
endocytosis of liquid or dissolved substances
process of active transport
binding - target molecule binds to specific protein pump
conformational change - energy released
release - target molecule is pushed through protein and released on the other side of the membrane
