5. DNA extraction
If we are looking at DNA, the first step is to extract the DNA from the tissue. To do this we first homogenise the cell of the tissue using a mini mortar and pestle. We then add chemicals to break down the cell membrane and remove the proteins and cell debris that is present.
The final purifying step is to add alcohol and salt. The DNA becomes insoluble and drops out looking like fine white cotton (right).
We then spin the mixture at high speed so that the DNA collects at the bottom of the tube (below right). The ethanol is removed and the DNA resuspended in water.
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