Sizes of cells

• Meter


  The base unit of measurement in science
• Sizes in biology

  • Often much smaller than a meter
• Centi


  One hundredth
• Centimeter (cm)


  One hundredth of a meter
• Size of objects


  • Width of little finger is around 1 cm
• Milli


  One thousandth
• Millimeter (mm)


  One thousandth of a meter
• Size of objects


  • Tip of a ballpoint pen is around 1 mm
• Micro


  One millionth
• Micrometer (μm)


  One millionth of a meter
• Size of objects


  • Typical human cell is 10-20 μm in size
• Nano


  One billionth
• Nanometer (nm)


  One billionth of a meter
• Size of objects


  • Hemoglobin molecule is around 5 nm in diameter
• Prefixes centi, milli, micro, and nano are used to describe sizes much smaller than a meter
• Micrometer and nanometer are particularly useful units for describing the size of cells and their components