Cell Requirements

Organic Compounds

• The building blocks of all living things.
• Contain Carbon (C), Hydrogen (H) and Oxygen (O) molecules.

Four types of organic compounds:

• Carbohydrates
  • Used for quick energy
  • Starch (stored in plant cells)
• Lipids
  • Contain many H and C molecules with a few O
  • Energy storage
  • Structural component of membranes
  • Essential parts of hormones
• Amino acids
  • Contain H, O, N and P molecules
  • Two types of Nucleic Acids:
    • DNA (deoxyribonucleic acid)
      • Stores information that controls cells.
      • Contains 4 bases: adenine, guanine, cytosine and thymine.
    • RNA (ribonucleic acid)
      • Large amounts in cytoplasm
      • Contains 4 bases: adenine, guanine, cytosine and uracil.

Inorganic Compounds

Five types of inorganic compounds:

• Water (H_{2}O)
  • Constitutes 70-90% of most organisms
  • Important solvent and transport medium
  • Chemical reactions in cells occur in water-based fluids
  • Some reactions include water (photosynthesis)
• Oxygen (O_{2})
  • Important for efficient energy supply, achieved by the process of cellular respiration in almost all organisms.
  • Taken in as a gas by terrestrial organisms and in solution by aquatic organisms.
• Carbon Dioxide (CO_{2})
  • Fundamental source of vital carbon atoms for organic molecules, usually starting carbon fixation by photosynthesis in autotrophs.
  • Taken into plant leaves as a gas, converted to sugars and eventually returns to the atmosphere in the carbon cycle.
• Nitrogen (N)
  • Makes up amino acids, which make up proteins.
  • Plants absorb from soil.
  • Absorbed by bacteria to make nitrates.
• Minerals
  • Make enzymes which are needed for the structure and function of biological systems.
  • Calcium is needed for bones and teeth.
  • Sodium and potassium are important for the nervous system.
  • Magnesium is important for muscular function.
  • Iron is required for haemoglobin.