There are three classes of food substances in the cell. These are: carbohydrates, lipids, and proteins.
Carbohydates are the substances that provide the body with energy. They can be classified into: Simple and Complex sugars. The simple sugars consists of Monosaccharides and disaccharides. The complex sugars are the polysaccharides.
Mono - means one, so monosaccharide means it consists of one sugar molecule. Di - means two, so the disaccharide consists of two sugar molecules. Poly - means many, so polysaccharides consists of more than two sugar molecules.
Examples of monosaccharides are glucose, fructose, galactose, and ribose sugars.
Examples of disaccharides are: maltose, lactose, and maltose.
Maltose is made up of two molecules of glucose. Maltose = glucose + glucose
Lactose is made up of glucose and galactose. Lactose = glucose + galactose.
Sucrose is made up of glucose and fructose. Sucrose = glucose + fructose.
- Galactose is found in dairy products, avocados, sugar beets, other gums and mucilages.
- Foods high in Maltose: wheat, cornmeal, barley, fruits such as peaches and pear.
- Lactose is found mainly in milk and dairy products such as cow's milk, goat's milk, yogurt, cheese and ice cream.
- Sucrose is found in fruits and vegetables, and is purified from sugar cane and sugar beets. The sucrose in your sugar bowl is the same sucrose found naturally in sugar cane, sugar beets, apples, oranges, carrots, and other fruits and vegetables.
- Sometimes called “fruit sugar,” fructose is a naturally occurring sugar found primarily in fruits (such as apples, dates, figs, pears and prunes), but also in vegetables (such as artichokes, asparagus, mushrooms, onions and red peppers), honey, sugar beets and sugar cane.
- Foods naturally high in pure glucose include honey, agave, molasses, dried fruit, fruits, fruit juices, and sweet corn.
LIPIDS
These are the fats and oils. Fats are solids at room temperature whereas oils are liquids at room temperature. A lipid is made up of fatty acids and glycerol. These are organic compounds. Lipids are sources of energy, insulation, and protection since they can act as cushions for organs.
PROTEINS
Protein is are made up of the building blocks called amino-acids. Amino acids have a central carbon that has amino and carboxylic groups attached to it. Your body needs 20 different amino acids to function correctly. Nine of these amino acids are called essential amino acids. Essential amino acids must be consumed through the food you eat. Essential amino acids can be found in a variety of foods, including beef, eggs and dairy. The other amino acids are called non-essential amino acids. They can be produced by the body.