The key features of cells and their functions - OCR 21st CenturyPreparing biological samples for examination

All living organisms are made of cells. Some contain only one cell. Others are multicellular and contain many cells.

Part ofBiology (Single Science)You and your genes

Preparing biological samples for examination

Aims of the experiment:

  • to stain cells for examination with a light microscope
  • to compare a range of cells and other structures with a microscope and to understand their basic structure
Image gallerySkip image gallerySlide1 of 3, biological samples for examination, Animal cells Cheek cells

The slides should not be viewed wet.

When viewing any slide with a microscope, a small square or circle of thin glass called a coverslip is placed over the specimen. It protects the microscope and prevents the slide from drying out when it's being examined.

The coverslip is lowered gently onto the specimen using a . It is important that no air bubbles are trapped underneath.

Most cells are colourless. Stains are used to add contrast. Certain stains are also used to stain specific cell structures or cell products.

Risks

  • Care must be taken when looking down the microscope if the illumination is too bright.
  • Care must be taken when using microscope stains.
  • Care must be taken when handling coverslips, microscope slides and mounted needles.