slk

• Carbohydrates


  Organic substances having C, H & O
• Saccharide


  From the Greek sacharon, meaning "sugar"
• Food rich in carbohydrates

  • Fruits
  • Rice
  • Bread
  • Pastas
  • Potatoes
  • Cereals
• Photosynthesis


  CO2 + H2O + energy → C6H12O6 + O2
• Glucose


  Sugar readily metabolized to CO2 and H2O with release of energy
• Types of Carbohydrates


  • Simple
  • Complex
• Simple Carbohydrates


  • Monosaccharides
  • Disaccharides

  
• Complex Carbohydrates


  • Polysaccharides
• Monosaccharides


  Basic carbohydrates that are sweet and soluble in water, possess a free aldehyde or ketone group and two or more hydroxyl groups, cannot be hydrolyzed further

  
• Monosaccharides


  • Glucose
  • Galactose
  • Fructose

  
• Disaccharides


  Two monosaccharides joined together by a covalent glycosidic bond, soluble in water and sweet

  
• Disaccharides


  • Sucrose
  • Lactose
  • Maltose
• Condensation Reaction


  Two monosaccharides combine to form a disaccharide, one molecule of water is lost
• Hydrolysis Reaction


  The bond between monosaccharides is broken with the addition of a water molecule
• Polysaccharides

  • Starch
  • Cellulose
  • Glycogen

  
• Starch


  Stored form of glucose in plants, important carbohydrate in human nutrition

  
• Cellulose


  Major component of rigid plant cell walls, composed of many monosaccharide units
• Glycogen


  Stored form of glucose in animals and humans, synthesized and stored mainly in the liver and muscles

  
• Structure of Starch


  1. Water molecule breaks the starch to produce H+ and OH-

  2. Enzymes help separate the glucose units in the digestive system

  3. Glucose is released to the cells gradually

  
• Athletes eat meals rich in complex carbohydrates before an athletic event

  Glucose from starch reaches muscle cells over a period of time providing energy as it is needed
• Glycogen


  A form of energy storage in animals and the main storage form of glucose in the body
• Glycogen

  • It is the readily available energy stored in liver and muscles and the one that is easily metabolized
  • It is used during prolonged exercise or activity
• Cellulose

  The basic component of plant cell walls
• Cellulose

  • Glucose molecules are arranged in such a way that hydrogen bonds link hydroxyl groups of adjacent glucose molecules to form insoluble fibrous sheets
  • It cannot be digested by humans but speeds up the movement of food through the digestive tracts
  • Herbivorous animals and insects can digest cellulose

  
• Economic importance of cellulose

  • Papers and fibers
  • Substances used in the manufacture of plastics, photographic films, and rayon
  • Adhesives, explosives, thickening agents for foods, and in moisture-proof coatings
• Economic importance of starch


  • Used in the manufacture of paper, textiles, pharmaceuticals, and biodegradable polymers, and as an additive in foods
• Lipids


  Energy-rich compounds made of carbon (C), hydrogen (H) and oxygen (O), including fats, oils, waxes and cholesterol

  
• Lipids


  Organic molecules that are insoluble in water (hydrophobic) but soluble in nonpolar solvents (alcohol, ether, benzene)
• Fats


  Lipids derived from animals
• Oils


  Lipids derived from plants
• Saponification


  The process of forming soap when fats and oils are heated with aqueous solution of bases
• Glycerol and fatty acids


  The building blocks of lipids

  
• Role of lipids

  • Fuel reserve of the body
  • Components of membrane structure and regulate the membrane permeability
  • Source of fat-soluble vitamins
  • Cellular metabolic regulators
  • Protect internal organs and serve as insulating materials
• Saturated fats


  Fats that are solid at room temperature
• Unsaturated fats


  Fats that are liquid at room temperature
• Hydrogenation of unsaturated fats


  Converts them to saturated fats
• Waxes


  Composed of long chains of fatty alcohols, or an ester of alcohols and fatty acids, do not mix with water
• Examples of waxes


  • Bees wax, lanolin or wool fat, sebum, cerumen, plant wax and paraffin wax
• Phospholipids


  Structurally similar to fats, but contain phosphorus and only two molecules of fatty acids, major components of cell membrane

  
• Steroids


  Naturally occurring lipid-soluble molecules, including cholesterol