Biology - Chapter 1

Biology - Chapter 1

1. Cell Structure and Transport

   • All living things are made up of cells, but some cells are so small you can only see them using a mircoscope
   • 1 kilometre (km) = 1000 metres (m)
   • 1 m = 100 centimtres (cm)
   • 1 cm = 10 millimetres (mm)
   • 1 mm = 1000 micrometers (µm)
   • 1 µm = 1000 nanometres (nm)
   • Mircoscopes
     • Light microscopes
       • The first light microscopes were developed in the mid-17th century
       • Light mircoscopes use a beam of light to form an image of an object and the best can magnify around 2000 times
       • Light microscopes are relatively cheap and can be used almost anywhere.
     • Electron mircoscopes
       • The invention of electron mircoscopes in the 1930s allowed biologists to see and understand more about the sub cellular structures inside cells.
       • The electron mircoscope uses a beam of electrons to form an image and can magnify objects up to around 2000000 times.
       • Electron microscopes are large, very expensive and have to be kept in a special temperature, pressure and humidity-controlled rooms.