Lipids pt 3

Glycosphingolipids and blood groups; blood groups are determined by

the type of sugars located on the head groups in glycosphingolipids

the structure of sugar is determined by

an expression of specific glycosyltransferases

• indv w/no active glycosyltransferase will have O antigen

• indv w/glycosyltransferase that transfers an N-acetylgalatosamine group have A blood group

• Indv w/glycosyltransferase that transfers an galactose group have B blood group

Sterol

steriod nucleus: four fuse rings (almost planar)

hydoxyl group (polar head) in the A-ring

Roles of sterols

• cholestrols and related sterols are present in eukaryotic mebranes

• mammals obtain cholesterol from food or synthesize it

• tarsnported to tissues via blood vesseels ( low-density lipoproteins deposit and clog arteries)

• hormones are derivatives of sterols

steroid hormones

• oxidied derivatives of sterols

• have sterol nuucleus but lack alkyl chain

• more polar tha cholestrol

• syntheized in adrenal glands

• man y are male and females sex hormones

Biological actuve lipids

• present in much smaller amounts than storage or structual lipids

• vital in signaling molecules between nearby cells

• lipid soluble vitamins (A,D,E, and K)

arachiodonic derivatives as signaling lipids

enzymayic oxidation of arechiodonic acid yeilds

• prostaglagins (inflammation and fever)

• thromboxanes (formation of blood clots)

• Luekotrienes (smooth muscle ocntraction in lungs)

vitamin D regulates

calcium uptake

Vitamin A (retinol)

• involves visual pigment

• precursor for other hormone involved in signaling

Vitamin E, K, and other lipid quinones are

antioxidants

polyketides are

biologically active lipids with medicinal uses