Molecular Techniques (DNA Isolation, Gel Electrophoresis)
Start with the big picture
Reliable DNA isolation aims to preserve high-molecular-weight DNA while removing proteins, RNA, lipids, and inhibitors. Lysis and protein removal can involve detergents, EDTA, and Proteinase K, followed by purification approaches such as phenol–chloroform extraction, silica spin columns, or alcohol precipitation. Purified DNA may be assessed using absorbance ratios and stored in a suitable buffer. In gel electrophoresis, negatively charged nucleic acids move toward the positive electrode through a porous matrix. Agarose and polyacrylamide serve different fragment-size and resolution needs; migration is compared with a DNA ladder to estimate fragment size. Sample preparation, buffer selection, staining, and DNA shape also influence interpretation.
What you'll learn
- Explain the roles of SDS, EDTA, and Proteinase K during DNA preparation.
- Distinguish phenol–chloroform, silica-column, and precipitation-based purification.
- Interpret DNA purity ratios and describe appropriate storage considerations.
- Explain how gel type and fragment size influence DNA separation.
- Identify how ladders, dyes, buffers, and DNA conformation affect gel analysis.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
