Class XII Practical: Biochemical & Physiological Experiments - DNA Isolation from Plant Material

Objective

To extract and observe DNA from common plant materials like banana, spinach, pea, or papaya.

Guidelines

1. Material Preparation: Take a small amount of fresh plant material (e.g., banana pulp, spinach leaves).
2. Homogenization: Mash or blend the plant material thoroughly to break open cells.
3. Lysis Buffer Preparation: Prepare a lysis buffer containing detergent (e.g., dish soap) to break down cell membranes, salt (e.g., NaCl) to neutralize DNA charge, and water.
4. Incubation: Mix the homogenized plant material with the lysis buffer and incubate at a warm temperature (e.g., 50-60°C) for a short period to aid cell lysis.
5. Filtration: Filter the mixture through a cheesecloth or sieve to remove large debris.
6. Enzyme Treatment (Optional): Add a protease (e.g., meat tenderizer) to digest proteins.
7. DNA Precipitation: Carefully add chilled ethanol or isopropanol to the filtrate. DNA will precipitate out as white, stringy strands at the interface of the two layers.
8. Observation: Spool the precipitated DNA onto a glass rod or observe it floating in the alcohol layer.

Expected Outcome

Visible strands of DNA extracted from plant cells, demonstrating the presence of genetic material.