AQA A Level Biology

Revision Notes

2.2.7 Scientific Research into Cell Organelles

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

Author:

Alistair graduated from Oxford University in 2014 with a degree in Biological Sciences. He has taught GCSE/IGCSE Biology, as well as Biology and Environmental Systems & Societies for the International Baccalaureate Diploma Programme. While teaching in Oxford, Alistair completed his MA Education as Head of Department for Environmental Systems and Societies.
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