Biological Molecules

• Carbohydrates, fats, and proteins are the main biological molecules in living organisms
• These molecules all contain carbon and are described as organic molecules
• Large molecules are made from smaller molecules:

  • Starch, glycogen, and cellulose are made from glucose
  • Proteins are made from amino acids
  • Fats and oils are made from fatty acids and glycerol
• Carbohydrates are long chains of simple sugars

  • Glucose is a simple sugar (monosaccharide)
  • Maltose is formed when 2 glucose molecules join together (a disaccharide)
  • Starch, glycogen, or cellulose can form when lots of glucose molecules join together (a polysaccharide)
• Fats/lipids are mostly made up of triglycerides

  • Triglycerides consist of 1 glycerol molecule chemically bonded to 3 fatty acid chains
  • Lipids are divided into fats (solids at room temperature) and oils (liquids at room temperature)
• Proteins are long chains of amino acids

  • There are over 20 different amino acids
  • Amino acids can be arranged in any order, resulting in hundreds of thousands of different proteins
  • Even a small difference in the order of amino acids results in a different protein being formed
• DNA is a double helix structure

  • It consists of two strands of DNA wound around each other
  • Nucleotides are the individual units of DNA
  • All nucleotides contain the same phosphate and deoxyribose sugar, but differ in the base attached
  • The four bases in DNA are Adenine (A), Cytosine (C), Thymine (T), and Guanine (G)
  • Adenine pairs with Thymine (A-T) and Cytosine pairs with Guanine (C-G)
  • The sequence of bases in DNA holds the code for the formation of proteins
• You do not need to learn the names of the bases, just their letter

  • Know which bases pair with each other, as this is a commonly asked question