Chapter 8: Lipids and Biological Membranes

Term
1 / 51
Roles of Lipids (4):
Click the card to flip 👆
Terms in this set (51)
Roles of Lipids (4):
1. Fuel molecules
2. High concentration of energy storage
3. Signal molecules
4. Components of membranes
How do we define lipids?
Solubility, lipids are marginally soluble in water, but readily soluble in organic solvents (like chloroform or acetone)
How are lipids classified?
Chemical nature: Open chain or fused-ring
What are open-chain lipids?
They have a polar head and nonpolar tails
What are some examples of open-chain lipids?
fatty acids, triacylglycerols, sphingolipids, phosphoacylglycerols, and glycolipids
What are some examples of fused ring lipids?
steroids like cholesterol
Define amphipathic:
Carboxyl group is hydrophilic and the hydrocarbon tail is hydrophobic
Do fatty acids normally have an even or odd number of carbon atoms?
Are they branched or unbranched?
Even
Unbranched
What is the definition of fatty acids?
Fatty acids are carboxylic acids that may or may not have a double bond in their hydrocarbon portion
Unsaturated Fatty Acid means:
there ARE double bonds in the chain
Saturated Fatty Acid means:there ARE NOT double bonds in the chainIn unsaturated fatty acids, are they normally cis or trans?cis double bonds (trans are rare)What notation do we use for fatty acids?# carbon atoms: # double bondsWhat affects the melting point in fatty acids?Degree of unsaturation -more double bonds = lower melting point Number of carbons -more carbons raises the melting pointWhat is Triacylglycerol?all three of the alcohol groups form ester linkages with fatty acidsWhat is phosphatidic acid?an alcohol group of glycerol is esterified by phosphoric acid rather than carboxylic acidWhere are phosphoacylglycerols found?plant and animal membraneWhat are Sphingolipids?Long chain amino alcohol sphingosine's -do not contain glycerol -found in both plants and animals -abundant in the nervous systemWhat are glycolipids?A carbohydrate bound to an alcohol group of a lipid by glycosidic linkageWhat are steroids?Fused rings containing 3 hexagons connected to 1 pentagonWhat steroid is of most interest in our discussion of membranes?CholesterolThe existence of lipid bilayers depends on ________ interactions.HydrophobicIf the hydrocarbon interior is rich in saturated fatty acid, it is _______ (rigid or fluid)rigidIf the hydrocarbon interior is rich in unsaturated fatty acid, it is _______ (rigid or fluid)fluidThe ______ cause disorder in the packing of lipid bilayer chainskinksThe presence of _________ in a membrane reduces fluidity by stabilizing extended chain conformations of the hydrocarbon tails of fatty acids.cholesterolThe lipid portion of a plant membrane has a higher percentage of ______(saturated or unsaturated) fatty acidsunsaturatedThe presence of _______ is characteristic of animal, rather than plant, membranescholesterolWhich are more rigid, plant or animal membranes?Animal membranes are more rigid than plant membranes because animal membranes contain cholesterolWhat are Myristoyl and Palmitoyl?common "anchors" -anchor proteins to biological membranesWhat are Transport Proteins?Help to move substances in and out of the cellWhat two classes are vitamins divided into?1. Lipid-soluble 2. Water-solubleLipids are compounds that consist mostly of nonpolar groups. They have limited solubility in _____, but dissolve freely in ________water organic solvents (like acetone or chloroform)Lipids are frequently open0chain compounds with a _____ head and a long ______ tailpolar nonpolar______, ______, and ______ are frequently obtained as degredation products of lipids.Glycerol Fatty acids and Phosphoric acidsAnother class of lipids consists of fused-ring compounds called:steroids (like cholesterol)Bulkier molecules tend to be found where in the lipid bilayer?in the outer layer, rather than the inner layerThe presence of ______ and ______ tends to stiffen the bilayersaturated fatty acids cholesterolThe packing of molecules in the bilayer can undergo a reversible transition from ______ to ______.order disorderProteins combine with lipid bilayers to form ______.membranesThe ______ of lipoprotein is generally beleived to be preventative of heart disease.HDL classFatty acids with ______ double bonds may be unhealthy because they increase the ratio of LDL's to HDL's.transPhospholipids are particularly important in:membrane lipids -membranes -lipoproteins -brian/nervous systemSphingolipids are particularly important to:membranes, the brain, and the nervous systemThe associagion of membrane proteins with lipids in the membrane bilayer always involves which interactions?-electrostatic interactions -hydrophobic interactions -covalent linkagesWhy would plant oils be favored in a diet?They contain more unsaturated fats than found in animal fatsWhich are healthier for humans, saturated or unsaturated fats?unsaturated fats are healthierHeart disease is correlated with diets that have high amounts of ______ (sat/unsat) fatssaturated fatty acids => heart disease______ (cis/trans) double bonds in fatty acids increase fluidity in a membranecis double bonds increase fluidity within a membraneWhy would animal fats be solid at a room temperature while a plant fat would be liquid?# of unsaturated hydrocarbons, more saturation lowers melting pointWhich of the following is not found in animal membranes? -triacylglycerols -phosphoacylglycerols -glycolipids -cholesterol -sphingolipidstriacylglycerols are not found in animal membranes