Chapter 3.2-3.3: The Molecules of Life

carbohydrates

a biological molecule consisting of simple single-monomer sugars (monosaccharides), 2-monomer sugars (disaccharides), and other multi-unit sugars (polysaccharides)

monosaccharides

the smallest kind of sugar molecule; a single unit-sugar; also known as simple sugar; are the complex building blocks of more complex sugars and polysaccharides

polysaccharides

a carbohydrate polymer consisting of many monosaccharides (sugars) linked by covalent bonds

disaccharides

a sugar molecule consisting of two monosaccharides linked by dehydration reaction

isomers

molecules that have the same molecular formula but different structures

starch

a storage polysaccharide found in the roots of plants and certain other cells; a polymer of glucose

lipid

an organic compound consisting mainly of carbon and hydrogen atoms linked by nonpolar convalent bonds and therefore mostly hydrophobic and insoluble in water; includes fats, waxes, phopholipids, and steroids

fat

a large lipid molecule made from an alcohol called glycerol and three fatty acids; a triglyceride; most fats function as energy storage molecules

triglyceride

a dietary fat, which consists of a molecule of glycerol linked to three molecules of fatty acid

unsaturated

pertaining to fats and fatty acids whose hydrocarbon chains lack the maximum number of hydrogen atoms and therefore have one or more double covalent bonds; do not solidify at room temperature

saturated

pertaining to fats and fatty acids whose hydrocarbon chains contain the maximum number of hydrogens and therefore have no double covalent bonds saturated fats and fatty acids solidify at room temperature

trans fat

an unsaturated fatty acids produced by the partial hydrogenation of vegetable oils and present in hardened vegetable oils; most margarines, commercial baked foods, and many fried foods

steroids

a type of lipid whose carbon skeleton is in the form of four fused rings: 3 6-sides rings and one 5-sided ring (i.e: choleserol, testosterone, and estrogen)

fatty acid

Organic compound that is a component of many lipids carboxyl group joined to a backbone of four to thirty-six carbon atoms. Backbone of saturated types has single bonds only that of unsaturated has double covalent bonds.

phospholipids

A lipid with a phosphate group in its hydrophilic head, and two nonpolar fatty acid tails main constituent of cell membranes.

wax

Water-repellent lipid with long fatty acid tails bonded to long-chain alcohols or carbon rings.