Cell Membranes Flashcards
what are some of the functions of cell membranes?
cell recognition, enzymatic functions, cell signalling
what does the cell membrane consist of?
phospholipids and cholesterol, polar glycolipids
what does cholesterol do in the membrane?
makes the bilayer less deformable and so less permeable to soluble molecules
how does cholesterol decrease permeability of the membrane?
immobilises the first few hydrocarbon groups of each phospholipid
what is the glycocalyx?
glycoprotein and glycolipid covering that surrounds the cell membranes of some bacteria
why is the glycocalyx useful?
for self-recognition and cell-cell adhesion
what is the bilayer permeable to?
non-polar molecules and hormones
what is the bilayer impermeable to?
ions and large molecules
what is the purpose of active transport?
to transport essential ions against their concentration gradient
what is primary active transport?
uses energy from the hydrolysis of ATP to pump substances across the membrane
what is secondary active transport?
uses the electrochemical gradient formed to transport the protein couple
what are the types of endocytosis?
receptor mediated, phagocytosis, pinocytosis
what is receptor mediated endocytosis?
used for transporting hormones and vitamins into cell membrane
what is pinocytosis?
bulk phase endocytosis where small droplets of extracellular fluid are taken in and no receptors needed
