CHEMISTRY OF LIPIDS

what are the types of lipids?

fats, oils, steroids, waxes

how are lipids related?

related by physical properties rather than chemical properties

what form of lipids is found in adipose tissues

triacylglycerol

how are lipids transported in the blood

combined with proteins, lipoproteins Signup and view all the answers

how do lipids act as insulators

thermal insulator: subcutaneous tissues and organs/ electrical insulator: allowing rapid propagation of depolarization waves along myelinated nerves Signup and view all the answers

what are amphipatic lipids?

part hydrophobic part hydrophilic lipids/ form membranes, micelles, liposomes & emulsions Signup and view all the answers

bilayer of amphipathic lipids forms?

biologic membranes Signup and view all the answers

how are micelles formed?

formed in an aqueous medium once a critical concentration of amphipathic lipids is reached Signup and view all the answers

how are liposomes formed? what is the structure?

formed by sonicating an amphipathic lipid in an aqueous medium/ consists of spheres of lipid bilayers that enclose part of the aqueous medium Signup and view all the answers

what is the clinical use of liposomes?

carriers of drugs in the circulation targeted to specific organs (ex. cancer chemotherapy) Signup and view all the answers

what are emulsions?

larger particles, formed usually by nonpolar lipids in an aqueous medium Signup and view all the answers

how are emulsions formed?

stabilized by emulsifying agents (amphipathic lipids [phosphatidylcholine]) forming a surface layer separating the main bulk of the nonpolar material from the aqueous phase Signup and view all the answers

what does an ester functional group consist of?

1 bond to carbon/ double bond to oxygen/1 bond to oxygen attached to R group (alkyl group) Signup and view all the answers

what are esters?

derivatives of carboxylic acids (OH --> O-R)/synthesized from the condensation of a carboxylic acid with an alcohol Signup and view all the answers

what is the carbonyl carbon and what does it do?

carbonyl carbon is the carbon that is bound to the R group and the oxygen/ it reacts with nucleophiles, bcz it is weakly electrophilic so can be attacked by strong nucleophiles Signup and view all the answers

what are the 4 classifications of lipids?

simple lipids/ complex lipids/ precursor & derived lipids/ neutral lipids Signup and view all the answers

what are simple lipids? examples?

fats or oils and waxes which are esters of fatty acids with various alcohols/ examples: fats, oils, waxes Signup and view all the answers

what are fats?

esters of fatty acids with glycerol (triacylglycerides) Signup and view all the answers

what are oils?

fats in the liquid state Signup and view all the answers

what are waxes?

esters of fatty acids with higher molecular weight monohydric alcohols (alcohols with one OH) Signup and view all the answers

what are complex lipids?

esters of fatty acids containing groups in addition to an alcohol & one or more fatty acids Signup and view all the answers

what are examples of precursor lipids?

fatty acids, glycerol, steroids Signup and view all the answers

what are examples of derived lipids?

fatty aldehydes, ketone bodies, hydrocarbons, lipid-soluble vitamins & micronutrients, hormones Signup and view all the answers

what are examples of neutral lipids?

uncharged molecules/ glycerides (acylglycerols)/ cholesterol/ cholesteryl esters Signup and view all the answers

what are the 2 ways in which fatty acids occur in the body?

esters in natural fats and oils/ unesterified form: free fatty acids Signup and view all the answers

give an example of a saturated fatty acid

palmitic acid, C16 Signup and view all the answers

give an example of a monounsaturated fatty acid (MUFA)?

oleic acid, C18:1 Signup and view all the answers

give an example of a polyunsaturated fatty acid (PUFA)?

linoleic acid C18:2 Signup and view all the answers

which carbon is the alpha carbon and which is the omega carbon?

carboxyl carbon is alpha and the terminal methyl carbon (furthest away) is the omega carbon Signup and view all the answers

what is the delta (triangle) used for when naming?

indicates the number and position of the double bonds Signup and view all the answers

what are the only possible places double bonds can be introduced in animals?

w9,w6, w3 or carboxyl carbon Signup and view all the answers

what is the structure of a saturated fatty acid?

no double bonds, CH2 is added btwn terminal CH3 and COOH groups Signup and view all the answers

give the list of saturated fatty acids with mnemonic and number of carbons

A BOOBS VAGINA CUNTY LESBIAN MASC PEES STEROIDS/ acetic 2/ butyric 4/ valeric 5/ caproic 6/ lauric 12/ myristic 14/ palmitic 16/ stearic 18 Signup and view all the answers

what is the occurrence of acetic acid?

major end product of carbohydrate fermentation by rumen organisms Signup and view all the answers

what is the occurrence of butyric acid?

in certain fats in small amounts (especially butter), an end product of carbohydrate fermentation by rumen organisms Signup and view all the answers

what is the occurrence of lauric?

spermaceti, cinnamon, palm kernel, coconut oils, laurels, butter Signup and view all the answers

what is the occurrence of myristic?

nutmeg, palm kernel, coconut oils, myrtles, butter Signup and view all the answers

what is the occurrence of palmitic?

common in all animal and plant fats Signup and view all the answers

what is the structure of saturated fatty acids at low and high temp?

low: zig zag pattern/ high: bonds rotate = chain shortening Signup and view all the answers

what are the 3 types of unsaturated fatty acids?

MUFA, PUFA & eicosanoids Signup and view all the answers

what are the 3 types of omega 3 fatty acids and where are they found?

AHA [ alpha linolenic] plants/ EPA [eicosapentaenoic acid][timnodonic] fish oils/ DHA [docosahexaenoic acid] [cervonic] fish oil, algal oil, phospholipids in brain Signup and view all the answers

what is the cis and trans configuration of fatty acids?

cis: acyl groups on same side of bond/ trans: opposite sides Signup and view all the answers

what is the preferred configuration of fatty acids and why?

cis configuration [bent 120 at double bond]/ bcz increases variety of spatial configurations (can pack more in less space) Signup and view all the answers

sources of trans fatty acids?

present in certain food, during hydrogenation of natural oils during margarine manufacture, ingestion of ruminant fat Signup and view all the answers

how do trans fatty acids affect health?

bad for health, associated with risk of diabetes, cvd and dm Signup and view all the answers

how does chain length affect melting point?

melting point increases with chain length, directly proportional Signup and view all the answers

how does unsaturation affect melting point?

melting point decreases with increase unsaturation, inversely proportional Signup and view all the answers

when are TAGs solid at body temperature

if there are 3 saturated FA of 12 carbons Signup and view all the answers

when can TAGs be liquid even below 0c?

if it has polyunsaturated residues Signup and view all the answers

lipids in extremities/ hibernators are more or less unsaturated?

more unsaturated Signup and view all the answers

since membranes must be fluid at all temperatures, how is the melting point different?

melting point decreases with chain length/ increases with unsaturation [opposite of normal] Signup and view all the answers

what are the health benefits of w3 fatty acids?

promotes the synthesis of less inflammatory prostaglandins and leukotrienes [anti-inflammatory] Signup and view all the answers

diets rich in w3 are beneficial for the treatment of what diseases?

cardiovascular diseases, cancer, rheumatoid arthritis, Alzheimer disease Signup and view all the answers

what enzyme phosphorylates glycerol? to form?

glycerol kinase --> sn-glycerol-3-phosphate Signup and view all the answers

what are the main constituents of membranes? they are derivatives of?

phospholipids. phosphatidic acid Signup and view all the answers

what makes up the glycerol backbone of phospholipids?

saturated acyl radical in sn-1 position & unsaturated radical in the sn-2 position Signup and view all the answers

what is the function of phosphatidic acid?

intermediate in synthesis of triacylglycerols and phosphoglycerols Signup and view all the answers

what is the most abundant phospholipid in the cell membrane?

phosphatidylcholines (lecithins) Signup and view all the answers

what is the function of phosphatidylcholines/lecithins?

a large portion of the body's store of choline Signup and view all the answers

what is the function of dipalmitoyl lecithin?

major constituent of surfactant, absence in infants causes RDS Signup and view all the answers

what is the function of the phospholipid, phosphatidylserine?

plays a role in apoptosis Signup and view all the answers