Chapter 3: Lipids

lipid functions

- biological membrane structures

- energy storage and transport

- cell signaling

- digestion

- metabolism

amphipathic

having both a hydrophilic region and a hydrophobic region

fatty acids

chains of carbon atoms bonded to hydrogen atoms

section of fatty acid that bonds molecule to other parts of lipid

carboxylic acid

glycerol

a three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils

head group

the polar, water-soluble region of a phospholipid that consists of a phosphate group linked to one of several small, hydrophilic molecules

cis unsaturated fatty acid

hydrogen atoms are nearly always on the same side of the two carbon atoms that are double bonded, low melting point, oils/liquids

trans unsaturated fatty acid

hydrogen atoms are on alternate sides or opposite from each other, produced artificially

saturated fatty acid

a long-chain hydrocarbon with single covalent bonds in the carbon chain; the number of hydrogen atoms attached to the carbon skeleton is maximized

* deposit more easily in arteries

essential fatty acids (EFAs)

fatty acids that must be consumed in the diet because they cannot be made by our body

eicosanoids

- regulatory molecules that can be synthesized from omega-3 and omega-6 fatty acids

- inflammatory mediators

esterification

a reaction of an alcohol with an acid to produce an ester and water

adipocytes

fat cells

lipids deliver __x the energy of glucose and glycogen

2x

burning fat molecules

fatty acid is cut for ATP generation & fat is depleted from cell

glycolipid

lipid with carbohydrate attached

ceramide

- simplest sphingolipid

- has a single hydrogen atom as its head group

- primary sphingolipid in humans

sphingolipid

sphingosine backbone + fatty acid tail + head group

what glycerol backbone is replaced by in humans

sphingosine

sphingomyelin

- class of sphingolipids and phospholipids (sphingophospholipids)

- have either phosphatidylcholine or phosphatidylethanolamine as a head group (contain phosphodiester bond)

- head groups have no charge

- major component of Schawnn cells and oligodendrocytes (cells that produce myelin)

cerebroside

- type of glycosphingolipid

- have a single sugar

- no net charge at physiological pH (neutral)

- found in neurons, muscle cells, and opioid receptors

sulfatide

- galactose-bound sphingolipid with sulfate group

- regular CNS cell growth

globoside

-type of glycosphingolipid

- have 2 or more sugars

-neutral

- determine ABO blood groups

cholesterol

- essential lipid found in eukaryotic membranes

- synthetic precursor to steroid hormones

- helps regulate lipid metabolism

lipoproteins

- complexes of lipid and protein molecules

- role in transportation and delivery of fatty acids, triacylglycerol, and cholesterol to and from target cells in a variety of organs

bile acids

cholesterol-containing acids found in the bile that act like detergents to break up fats in the small intestine

examples of what can be made from cholesterol

- bile acids

- sex hormones

- adrenal hormones

- vitamin D

vitamin D production

- formed in skin from 7-dehydrocholesterol

- required for calcium and phosphate homeostasis

calcitriol

active form of vitamin D

functional group formed when joining fatty acids

ester