Isolating DNA: open the cell, clean up, spool.

Getting pure DNA: pick the right wall-breaking enzyme for the cell, strip RNA and protein, then spool DNA from chilled ethanol.

Spool pure DNA from a fungal cell with no wasted or wrong reagents.

Using lysozyme to break open plant or fungal cells.

• The process runs in order: isolate DNA, cut it with restriction endonucleases, isolate the wanted fragment, ligate it into a vector, transfer it into the host, culture the host on a large scale, and extract the product.
• DNA must be pure, free of other macromolecules, before restriction enzymes can cut it. It lies within membranes, so cells are broken open to release it along with RNA, proteins, polysaccharides and lipids.
• Cell walls are broken with enzymes: lysozyme for bacteria, cellulase for plant cells, and chitinase for fungi.
• Genes lie on long DNA molecules wound around proteins such as histones. RNA is removed with ribonuclease and proteins with protease; other molecules have their own treatments.
• Adding chilled ethanol makes the purified DNA precipitate as fine threads in the suspension, which can be removed by spooling.
• Purified DNA is incubated with the restriction enzyme under that enzyme's optimal conditions. Agarose gel electrophoresis checks how far the digestion has gone, with DNA moving towards the anode. The vector DNA is cut the same way.
• The cut gene of interest and the cut vector are mixed and ligase is added, which gives recombinant DNA.

Teaching this idea? Put the simulation on your own page or LMS with this code.