Biological molecules

Monomers and Polymers

Monomers are small units from which larger molecules are made

Polymers are molecules that are made from a large amount of monomers joined together

examples of monomers are monosaccharides nucleotides and amino acids.

condensation reaction joins together with the formation of a chemical bond involves the elimination of water

Hydrolysis reaction is a chemical reaction that involves the gain of water

examples of polymers include nylon, polyethylene, polyester, Teflon, and epoxy.

Carbohydrates

monosaccharides are the monomers from which larger carbohydrates are made. Glucose, galactose and fructose are common monosaccharides.

Disaccharides are formed by the condensation of two monosaccharides

maltose is a disaccharide formed by condensation of two glucose molecules

sucrose is a disaccharide formed by condensation of a glucose molecule and a fructose molecule

lactose is a disaccharide formed by condensation of a glucose molecule and a galactose molecule.

a condensation reaction between two monosaccharides forms a glycosidic bond.

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A condensation reaction between two monosaccharides forms a glycosidic bond:

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Polysaccharides are formed by the condensation of many glucose units.

Glycogen and starch are formed by the condensation of α-glucose.

Cellulose is formed by the condensation of β-glucose.

Lipids

Triglycerides and phospholipids are two groups of lipid.

Triglycerides are formed by the condensation of one molecule of glycerol and three molecules of fatty acid.

A condensation reaction between glycerol and a fatty acid (RCOOH) forms an ester bond.

The R-group of a fatty acid may be saturated or unsaturated.


In phospholipids, one of the fatty acids of a triglyceride is substituted by a phosphate-containing group.


The emulsion test for lipids.

Proteins

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where NH2 represents an amine group, COOH represents a carboxyl group and R represents a side chain. The twenty amino acids that are common in all organisms differ only in their side group.


A condensation reaction between two amino acids forms a peptide bond.

Dipeptides are formed by the condensation of two amino acids.

Polypeptides are formed by the condensation of many amino acids.