Lifesciences term 1 and term 2

• Substances that cells are made up of

  • Proteins
  • Carbohydrates
  • Lipids
  • Nucleic acids (DNA and RNA)
  • Vitamins
• All substances are made up of

  • Atoms
  • Elements
  • Minerals
  • Compounds
• Types of compounds


  • Organic
  • Inorganic
• Components of living organisms

  • Nucleic acids
  • Water
  • Carbohydrates
  • Proteins
  • Lipids
  • Vitamins
• Types of minerals


  • Macro elements
  • Micro elements
• Macro elements


  Nutrients that are needed in large quantities
• Micro elements


  Nutrients that are needed in small quantities
• Sodium (Na)


  • Important for maintaining water balance in the human body
  • Required for functioning of nerves and muscles
• Potassium (K)

  • Required for functioning of nerves and muscles
  • Needed to activate plant enzymes
• Calcium (Ca)

  • Required for formation of bones and teeth in animals
  • Plays a role in the permeability of cell membranes
• Phosphorus (P)

  • Required for formation of bones and teeth in animals
  • Component of cell membranes and nucleic acids
• Iron (Fe)

  • Required in systems of hemoglobin
  • Helps to form chlorophyll in plants
• Iodine


  • Components of the hormone thyroxin which is secreted by the thyroid gland in humans
• Carbohydrates


  • Made up of the elements carbon (C), hydrogen (H) and oxygen (O)
  • Ratio of H atoms to O atoms is 2:1
• Types of carbohydrates

  • Monosaccharides (single sugars)
  • Disaccharides (double sugars)
  • Polysaccharides (many sugars)
• Monosaccharides


  eg glucose, fructose, galactose
• Disaccharides

  • eg maltose, sucrose, lactose
  • Formed when 2 monosaccharides are joined
• Polysaccharides


  • eg starch, glycogen, cellulose
  • Made up of long chains of monosaccharides
• Atoms


  Smallest building blocks of matter
• Molecules


  Formed when atoms combine, can be as little as two atoms or composed of many hundreds of atoms
• Cells


  Basic unit of life, require simple and complex molecules
• Elements


  Consist of identical atoms
• Compounds


  Formed when two or more different elements combine
• Compound


  • Water (H2O)
• Inorganic substances


  Do not contain carbon (except for CO2 and carbonates), usually small molecules composed of a few atoms, e.g. water and mineral salts
• Water


  • Essential for plants and animals, required for photosynthesis, plays an important role in nutrition, provides a fluid medium for chemical reactions
• Mineral salts


  • Sodium (Na)
  • Potassium (K)
  • Calcium (Ca)
  • Phosphorus (P)
  • Iron (Fe)
  • Iodine (I)
• Macro elements


  Na, K, Ca and P, required in large quantities by humans
• Micro elements


  Fe and I, required in small quantities by humans
• Fertilisers


  Used by farmers to enrich the soil with minerals like nitrates and phosphates
• Excessive use of fertilisers


  Results in some of it being drained into rivers and dams, leading to eutrophication and death of aquatic life
• Organic compounds


  Contain the element carbon, usually bonded with hydrogen, may also contain oxygen, nitrogen and phosphorus
• Examples of organic compounds

  • Carbohydrates (sugars and starch)
  • Lipids (fats and oils)
  • Proteins
  • Enzymes
  • Vitamins
  • Nucleic acids
  • Vinegar
  • Alcohol
  • Aspirin
  • Plastics
• Carbon dioxide (CO2) is an inorganic compound
• Carbohydrates


  Organic molecules made up of carbon, hydrogen and oxygen, with a hydrogen to oxygen ratio of 2:1, serve as the main source of energy for living organisms
• Monomers of carbohydrates


  Saccharides (sugars)
• Types of carbohydrates


  • Monosaccharides (single sugars)
  • Disaccharides (double sugars)
  • Polysaccharides (many linked sugars)
• Lipids


  Organic compounds containing carbon, hydrogen and oxygen, with a hydrogen to oxygen ratio greater than 2:1, may also contain phosphorus (phospholipids)
• Saturated fats


  Have single bonds in the fatty acid chains
• Unsaturated fats


  Have 1 or more double bonds in the fatty acid chains