BIOLOGICAL MOLECULES

About 96.3 percent of the total human body weight is made of the elements: carbon, oxygen, hydrogen, and nitrogen. Mostly of which are found in the tissues, body fluids, and organisms are called organic compounds.

THE PRINCIPAL TYPES OF BIOLOGICAL MOLECULES

1. Carbohydrates – Carbohydrates are composed of carbon, hydrogen, and oxygen in the ratio of 1C:2H:10 and include the different types of sugar and starch. They are the main sources of energy in organisms.

CLASSIFICATION OF CARBOHYDRATES

a) Monosaccharides are simple sugars. The most important monosaccharides are glucose, galactose, fructose, and ribose.
Glucose is the sugar produced by plants during the food making process. It is present in the blood and tissues of mammals in a concentration of 0.1 percent by body weight.
Galactose is found in milk. Fructose is the sweetest sugar and commonly found in fruits. They have a common formula of C 6 H 12 O6 They only differ in the arrangement of their individual atoms.

b)Disaccharides are carbohydrates made of two simple sugar units. These double sugars have the formula C 12 H 22 0H. These are sugars which contained cereal grains.
Sucrose or table sugar consists of one molecule of glucose and one of fructose.
Maltose or malt sugar is composed of two molecules of glucose.

c) Polysaccharides are carbohydrates made of more than two simple sugar. There are hundreds of monosaccharides linked together.

Classes of Polysaccharides

1) Starch is found in both plant and animal cells. Its molecules contain about 250-1,000 glucose units. The glucose units are made from carbon dioxide and water by photosynthesis. Glucose units produced are polymerized into starch as food reserve in the plant and animal body. Some examples are bread, pasta, and potatoes.

(2) Glycogen or animal starch is stored in the liver and muscles.

(3) Chitin forms the exoskeleton of arthropods.
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4) Cellulose is contained in the cell walls of plants and gives them strength an" rigidity.

2. Lipids include fats, waxes, and oils which serve as fuels and as structural components of cells especially cell membranes.They are formed by combining smaller compounds such as fatty acids and glycerol. They are nonpolar organic molecules that do not dissolve in water.

Two TYPES OF LIPIDS

A. Simple lipids

(1) Fatty acids, a long chain carbon skeleton that has a carboxylic acid functional group (-COOH) attached to one end. Glycerol is a 3- carbon alcohol that contains three hydroxyl groups (-OH ).

(2) Fats and Oils are triglycerides of fatty acids.

B. Compound Lipids are the products of fatty acids esterified with other organic compounds. Example is phospholipids which yield alcohol, fatty acid, phosphoric acid, and a nitrogen base upon hydrolysis.

3. Proteins are the building blocks of living material which are made up of amino acids. Proteins are important in the growth, maintenance and repair of tissues. Amino acid contains a central carbon atom to which is attached a carboxyl group (-COOH), a hydrogen atom, and an amino group (-NH, ). Also attached to the carbon atom is the rest of the molecule that makes each amino acid different. This is represented by R. An amino acids join together are called peptides. Many amino acids joined together form a polypeptide. Structural proteins form the hair and nails while other proteins include hemoglobin, the oxygen carrier of the blood.

ENZYMES

All living organisms need energy and building materials for growth and reproduction. The formation, breakdown and rearrangement of those molecular materials are facilitated by chemical reactions. In order to control the chemical reactions without increasing the temperature, Substances called catalysts are needed. A catalyst is a chemical that speeds the reaction by lowering the amount of activation energy needed to start the reaction. A cell manufactures specific proteins that act as catalyst. A protein molecule that acts as a catalyst to change the rate of a reaction is called an enzyme. The instructions for the manufacture of all enzymes are found in the genes of the cell. Enzymes accelerate a reaction at 10,000,000,000 times faster. A reaction takes as long as 1,500 years without an enzyme but can be completed in just 5 seconds. Enzymes speed up reaction by binding to the reactants which are substances es that enter into a chemical reaction. The reactants that are affected by an enzyme are known as substrates. Substrates bind to enzymes at a region k known as the active site. Enzymes are very specific. Particular enzyme can catalyze only one particular chemical reaction involving specific substrates. The enzyme's active site and its substrate exactly fit to each other similar to a lock and key.
Enzymes are involved in all cells' cellular processes such as digestion, respiration, reproduction, synthesis, and in the production of variety of products such as microbial enzymes, meat tenderizer, stain remover, and probiotics.

CLASSES AND USES OF ENZYMES

These have systematic names which end in -ase, which incorporate the name of the substrate with which they react and often the kind of reaction they catalyze.

Urease – converts urea to carbon dioxide and ammonia

Tryptophan synthetase – synthesizes the amino acid tryptophan

Beta galactosidase – synthesizes lactose from milk

Restriction endonuclease <– acts as scissors to cut DNA

Enzymes are utilized in the production of pharmaceutical and industrial products. They are used to break down corn starch to produce fructose and dextrins. All fermentation processes depend on enzymes. Growth hormones and insulin are enzyme-based products.