BCH 414 Dr Enadeghe.docx

Macromolecules

Macromolecules

Large molecules essential for life, composed of repeating subunits called monomers, joined by covalent bonds to form larger polymers.

Carbohydrates

Biomolecules containing hydroxyl groups and aldehyde or ketone groups, classified into monosaccharides, disaccharides, and polysaccharides, providing energy and serving various functions in living organisms.

Disaccharides

Composed of two monosaccharide units joined by a glycosidic linkage, such as maltose, lactose, and sucrose, hydrolyzed to simpler sugars by enzymes or acids.

Proteins

High molecular weight polymers of amino acids linked by peptide bonds, essential for life processes, functioning as enzymes, regulators, transporters, and structural components in living cells.

Globulins

Water insoluble but soluble in dilute neutral salt solution, heat coagulable, precipitated by ammonium sulphate. Examples include serum globulins, fibrinogens, and muscle myosin.

Protamines

Small molecules soluble in water, dilute acids, alkalies, non-coagulable by heat, basic proteins in the body, combine with nucleic acid to form nucleoproteins. Examples are salmine, sardimine, and cyprimine.

Histones

Rich in arginine and histidine, soluble in water, dilute acids, salt solutions, insoluble in ammonia, do not readily coagulate on heating. Examples include the protein part of haemoglobin and globin.

Gliadins (Prolamines)

Alcohol-soluble plant proteins, insoluble in water, salt solutions, absolute alcohol, rich in proline. Examples are gliadins of wheat and hordein of barley.

Glutelins

Plant proteins insoluble in water or neutral salt solutions, soluble in dilute acids or alkalies, rich in glutamic acid, coagulated by heat. Examples are oryzenin of rice and glutelin of wheat.

Saponification

The hydrolysis of a fat by alkali resulting in the formation of glycerol and alkali salts of fatty acids, known as soaps.

Saponification Number

The amount of milligrams of KOH required to saponify 1 gram of fat or oil.

Acid Number

The quantity of milligrams of KOH needed to neutralize the free fatty acids in 1 gram of fat.

Iodine Number

The measure of the degree of unsaturation of a fat, indicated by the grams of iodine absorbed by 100 grams of fat.

Acetyl Number

The milligrams of KOH necessary to neutralize the acetic acid produced by saponification of a gram of fat after acetylation, indicating the number of hydroxy acid groups in the fat.

Halogenation

Addition of halogen atoms (chlorine, bromine, iodine) to the double bonds of unsaturated fatty acids in fats.

Rancidity

The oxidation of natural fats when exposed to air, light, and moisture, leading to an unpleasant taste and odor due to peroxides formation at the double bonds of unsaturated fatty acids.

Hydrogenation

Conversion of unsaturated plant fats into more saturated and solid fats by catalytic hydrogenation, often using nickel, exploited in the production of margarine and vegetable shortening.

Lipoproteins

Molecules combining lipids and proteins, crucial for lipid transfer to tissues and maintaining cellular integrity.

Nucleic Acids

Essential macromolecules in living organisms, including DNA and RNA, responsible for storing, transmitting, and expressing genetic information.