L I P I DSpirit for Research

STANDAR KOMPETENSIMendeskripsikan struktur, klasifikasi, sifat danfungsi lipid dalammetabolisme dankehidupan sehari-hari

KOMPETENSI DASAR Menuliskan rumus struktur lipid Mengklasifikasikan lipid Mengamati dan menjelaskan sifat fisika dan sifat kimia lipid Menjelaskan fungsi lipid dalam metabolisme dan kehidupan sehari-hari Merancang dan melakukan percobaan untuk mengidentifikasi lipid

THE FACT OF LIPIDS* a class of hydrocarbon-containing organic compounds* water-insoluble & soluble in nonpolar organic solvents* Lipid is not polymers* Fat is a subgroup of lipids called triglycerides* Lipids yield 9 kcal of energy/gram while carbohydrates and proteins yield only 4 kcal energy/gram* lipid reserves containing 100,000 kcal of energy can maintain human body functions without food for 30-40 days with sufficient water. Meanwhile Free glucose only 40 kcal (for a few minutes), Glycogen only 600 kcal (about one day) and Protein (mostly in muscle) contains a substantial energy reserve of about 25,000 kcal.

CLASSIFICATION OF LIPIDFatty acids- Saturated- Unsaturated2. Glycerides or glycerolipids- Monoglycerides- Diglycerides- Triglycerides (neutral fats)- Phosphoglycerides or glycerophospholipids3. Nonglycerides- Sphingolipids- Sterol lipids, includes cholesterol and steroid hormones- Prenol lipids, includes terpenoids- Waxes- Polyketides4. More complex lipid derivatives- Sugar-linked lipids: glycolipids- Protein-linked lipids

CLASSIFICATION OF LIPIDBased on their reactivity with strong bases:- SaponifiableNonsaponifiable include the "fat-soluble" vitamins (A, E) and cholesterol. Based on the backbone structures:

Major Roles of Biological of LipidsHave three major functions: They serve as structural components of biological membranes. Eg. Membrane proteins

Major Roles of Biological of LipidsOne of the principal types of lipid in the membrane include the phospholipids.

The lipid bilayer gives the membranes its fluid characteristics.

Another type of lipid in the membrane is cholesterol

Glycolipids are also a constituent of membranes.

2. They provide energy reserves, predominantly in the form of triacylglycerols

Major Roles of Biological of Lipids2. They provide energy reserves, predominantly in the form of triacylglycerols

Major Roles of Biological of Lipids3. Both lipids and lipid derivatives serve as vitamins and hormonesH O M E W O R K

Fatty AcidsFatty acids fill two major roles in the body: as the components of more complex membrane lipids. as the major components of stored fat in the form of triacylglycerols.

Fatty AcidsCOMMON BIOLOGICAL SATURATED FATTY ACIDS

SymbolCommon NameSystematic NameStructuremp(0C)12:0Lauric aciddodecanoic acidCH3(CH2)10COOH44.2

14:0Myristic acidtetradecanoic acidCH3(CH2)12COOH5216:0Palmitic acidHexadecanoic acidCH3(CH2)14COOH63.1

18:0Stearic acidOctadecanoic acidCH3(CH2)16COOH69.620:0Arachidic acidEicosanoic acidCH3(CH2)18COOH75.4

COMMON BIOLOGICAL UNSATURATED FATTY ACIDS

SymbolCommon NameSystematic NameStructuremp(0C)16:1D9Palmitoleic acidHexadecenoic acidCH3(CH2)5CH=CH-(CH2)7COOH-0.518:1D9Oleic acid9-Octadecenoic acidCH3(CH2)7CH=CH-(CH2)7COOH13.418:2D9,12Linoleic acid9,12 -Octadecadienoic acidCH3(CH2)4(CH=CHCH2)2(CH2)6COOH-918:3D9,12,15a-Linolenic acid9,12,15 -Octadecatrienoic acidCH3CH2(CH=CHCH2)3(CH2)6COOH-17

20:4D5,8,11,14arachidonic acid5,8,11,14- Eicosatetraenoic acidCH3(CH2)4(CH=CHCH2)4(CH2)2COOH-49

20:5D5,8,11,14,17EPA5,8,11,14,17-Eicosapentaenoic- acidCH3CH2(CH=CHCH2)5(CH2)2COOH-54

Fatty AcidsLinoleic acid and linolenic acid (unsaturated FA) are biological precursors for other PUFAs, but they cannot be synthesized from precursors in the body, and are thus considered the essential fatty acids.

Essential means they must be provided in the diet by consuming a variety of plants or the meat.

Glycerides

Monoglyceride (a-monostearin)Diglyceride (a, a'-distearin)Triglyceride (b - palmityl distearin)

Glycerolipids

X = ethanolamine (phosphatidylethanolamine)choline (phosphatidylcholine, also called lecithins) serine (phosphatidylserine)glycerol (phosphatidylglycerol)myo-inositol (phosphatidylinositol

Glycerolipids - Phospholipids

^ Other name phosphatides

^are natural surfactants and emulsifiers found inall plants and animals and include such substances as lecithin, cephalin, and sphingomyelin

^Lecithin or phosphatidylcholine, is a significant constituent of brain and nervous tissue consisting of a mixture of diglycerides ofstearic, palmitic, and oleic acids, linked to the choline ester of phosphoric acid

Nonglycerides - Sphingolipids^ Sphingomyelin is an abundant sphingolipid generated by transfer of the phosphocholine moiety of phosphatidylcholine to a ceramide^ Glycosphingolipids consist of:Cerebrosides: contain a single moiety galactose Sulfatides: sulfuric acid esters of galactocerebrosidesGlobosides: contain 2 or more sugarsGangliosides: similar to globosides except also contain sialic acid

Nonglycerides Sterol lipids

Sterols are alcohols also found in steroid hormones such as testosterone, progesterone, and cortisol Cholesterol is produced by the liver and is found in all body tissues where it helps to organize cell membranes and control their permeability Cholesterol derivatives in the skin are converted tovitamin D when the skin is exposed to sunlight Vitamin D3 mediates intestinal calcium absorption and bone calcium metabolismA high level of cholesterol in the blood is considered to be a risk factor for cardiovascular diseases

Nonglycerides Waxes

- Fatty acids + Long chain alcohol Important in fruits:1. Natural protective layer in fruits, vegetables, etc.2. Added in some cases for appearance and protection.Beeswax (myricyl palmitate)Spermaceti (cetyl palmitate)