Scientific Research into Cell Organelles (AQA A Level Biology)

Appreciating the Process of Distinguishing Organelles

• When looking at a prepared sample (e.g. a cell or a group of cells) under a microscope, you can sometimes see things that aren’t actually part of the specimen

• These are known as artefacts

• Artefacts can be a variety of things, such as:

  • dust

  • air bubbles

  • fingerprints

• These artefacts often occur during the preparation of a sample

  • During preparation, a sample is often squashed or stained, which can generate artefacts

  • The occurrence of artefacts can be decreased by more careful preparation of samples

• Artefacts are common in electron micrographs (especially in samples prepared for viewing using a transmission electron microscope) due to the lengthy treatment required to prepare samples

• This was particularly problematic for early research by scientists using the first electron microscopes

  • To distinguish between artefacts and organelles, they had to repeatedly prepare a specimen in different ways, using different techniques

  • If they saw a particular object in a specimen prepared using one preparation technique, but not another, the object was more likely to be an artefact than an organelle

• This was a problem for the scientific community that persisted for a considerable period of time until preparation techniques and knowledge of organelles improved