BIOMOLECULES

• The four biomolecules

  • Carbohydrate
  • Lipid
  • Protein
  • Nucleic Acid
• Carbohydrate


  Provides energy to the body, particularly through glucose (sugar) and have other functions in humans, animals, and plants
• Carbohydrates

  • Most abundant class of organic compounds found in all living things
  • Include sugars, starches, cellulose, and many other compounds
  • Have a H:C:O ratio of 2:1:1. Cn(H2O)n
  • Either formed from or decomposed into other carbohydrate form through the physiological process
  • Play a key role in energy production and storage
• Functions of carbohydrates

  • It serves as the backbone of other molecules
  • It serves as stored energy (such as starch, cellulose, glycogen)
  • It is the most common source of energy in the body
  • It combines with proteins (glycoproteins) to form structural components of living cells
• Role of carbohydrates in photosynthesis

  1. Carbohydrates are synthesized by green plants during photosynthesis, a complex process in which sunlight provides energy to convert CO2 and H2O into glucose plus oxygen

  2. Many molecules of glucose are then chemically linked for storage by the plant in the form of starch

  3. Cellulose is present in the cell wall of a plant and helps the cell maintain the shape of a plant

  4. Starch, which are stored in the seeds and serve for a growing plant
• Classifications of carbohydrates

  • Monosaccharides
  • Disaccharides
  • Polysaccharides
• Monosaccharides


  Simplest form of sugar, all are reducing sugars, are crystalline white solids at room temperature, polar and highly soluble in water, further classified as aldoses or ketoses
• Monosaccharides


  • Glucose
  • Galactose
  • Fructose
• Disaccharides


  Made up of two monosaccharide units joined by glycosidic bond, all have a molecular formula of C12H22O11, formed by condensation reaction and broken down by hydrolysis
• Disaccharides


  • Sucrose
  • Lactose
  • Maltose
• Reducing sugars


  Carbohydrates that contain aldehyde group, which can be oxidized to a carboxylic acid group
• Polysaccharides


  A long chain of ten monosaccharide units or more joined together
• Polysaccharides


  • Glycogen
  • Starch
  • Cellulose