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Cell Membrane Structure

Terms in this set (16)

phospholipid
One of the most common types of membrane lipids, having a polar, hydrophilic head and a nonpolar, hydrophobic tail. They have a phosphate head and two fatty acid tails.
cholesterol
A lipid that forms an essential component of animal cell membranes and is the building block for steroid hormones such as estrogen and testosterone, and the building block for vitamin D.
role of cholesterol in cell membranes
helps both prevent the membrane from being too permeable, and also helps it remain fluid so that things can move as needed within the membrane. Also important in localizing proteins to the right spot in the membrane
peripheral proteins
Proteins loosely attached to the surface of the membrane. Often are enzymes or important in signaling
channel protein
A membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel.
Na+/K+ ATPase pump
channel protein that transports 3 Na+ out of cytoplasm for every 2 K+ moved in. This causes the resting membrane potential to be relatively negative; Na+ to be highly concentrated OUTSIDE of cells and K+ to be highly concentrated INSIDE of cells.
antigen
On our cells, antigens can be glycoproteins that serve as Identification tags. On bacteria or viruses, these antigens may trigger an immune response from our body. Or, our immune system may attack our OWN antigens and cause an autoimmune disease.
glycoprotein
short sugar chains attached to proteins - on our cells, these often serve as antigens that identify the cell.
autoimmune
the immune system's attack on the body - specifically when it inappropriately recognizes our own cell's antigens.
allergy
a specific reaction of the immune system to a antigen on a harmless substance found in the environment -- foods or medicine, for example
actin
long thin protein that can give shape to the cell membrane; for example in microvilli of intestinal cells or dendrites of neurons. In muscle cells, actin is pulled on by myosin to produce muscle contraction.
roles of unsaturated fatty acids in the membrane
signaling (especially inflammation)
flexibility
saturated fatty acids in the membrane
stabilizes cell membrane
cholesterol in the cell membrane
keeps the membrane from getting too floppy at slightly warmer temps and from getting too rigid at slightly cooler temps
localizes proteins to the correct spot in the membrane
reduces permeability of the membrane to substances so that nothing passes through that shouldn't
integral proteins or transmembrane proteins
membrane proteins that can enter the hydrophobic regions of the bilayer, or even go all the way through the bilayer
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