Cell Structures

• Calculating Cell Size

  1. Count the number of cells going from one side to another

  2. Divide the diameter of the field of view by the number of cells

  3. Convert to micrometres if required
• Cells are measured in micrometres (µm)
• 1 millimetre is equal to 1000 micrometres
• Cells are the building blocks of all living organisms and are the unit of life
• 1mm = 1000μm
• Inside a cell are structures called organelles which are responsible for specialized functions
• When viewing cells under a microscope, a chemical stain is used to make organelles more visible
• Chloroplast


  Site of photosynthesis
• Cytoplasm

  Jelly-like substance inside the cell where many cellular activities take place
• Cellulose


  The structural carbohydrate of which plant cell walls are composed
• Cytoplasm


  Site of chemical reactions in a cell
• Cell membrane


  Controls what substances can enter or exit the cell
• Plasmid


  Circular piece of DNA present only in bacterial cells
• Ribosome


  Site of protein synthesis
• Vacuole

  Membrane-bound sac containing cell sap in plant and fungal cells
• Nucleus

  Contains genetic material (DNA)
• Mitochondria


  Site of aerobic respiration
• Cell wall


  Provides the cell with shape and support
• Nucleus


  Controls cell activities