Read DNA from Extraction to Separation
Biotechnology workflows depend on extracting DNA and separating fragments by size.
DNA Isolation and Gel Electrophoresis is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Extract the molecule
Cellulase helps break plant cell walls; chitinase helps digest fungal walls. After lysis and cleanup, chilled ethanol precipitates DNA.
Separate fragments
Agarose comes from seaweeds. DNA fragments move through the gel and separate mainly by size; smaller fragments generally travel farther. Ethidium-bromide-stained DNA is visualised under UV light, and more concentrated agarose has smaller pores.
Choose a DNA-rich tissue
A tissue rich in nucleated cells yields more DNA per unit mass. The thymus contains many lymphocytes, whose high nucleus-to-cytoplasm ratio makes it a useful extraction source; softness, vestigial status, or a guaranteed high division rate is not the reason.
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- ✓Plant wall: cellulase; fungal wall: chitinase.
- ✓Cold ethanol precipitates DNA.
- ✓Agarose is from seaweeds.
- ✓Smaller fragments migrate farther; stain is seen under UV.
Do not confuse the light used to visualise stained DNA with visible light.
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