Saturday Science: Wheat Germ DNA Extraction
To extract the DNA from raw wheat germ, we must first break open the cellulose cell wall; the DNA precipitates out because it is insoluble in ethanol, and the DNA can then be spooled onto a wooden stick.
Materials
1 gram raw wheat germ, 20 mL hot water, 10 mL alcohol, 2 mL dishwashing detergent, 1 mL washing powder, 1.5 mL warm water, 1/4 cup sugar, 1 tbsp flour, 1 tsp baking powder, 0.1 tsp salt, 0%
Process
Shake vigorously for 3 minutes with 1 gram raw wheat germ, 20 mL hot water, and 10 mL ethanol or rubbing alcohol. The white precipitate will contain wheat genomic DNA, as well as some polysaccharide or protein, such as protein and carbohydrate.
Why is it important for scientists to purify DNA from cells?
Scientists can observe, manipulate, and classify DNA after removing it from an organism, which allows them to identify genetic disorders or diseases and possibly find cures for these causes by manipulating or experimenting with the DNA.
Why is it easy to isolate DNA from strawberries?
Ripe strawberries are a great source of DNA because they’re easy to pulverize and contain enzymes called pectinases and cellulases that help break down cell walls. Plus, strawberries have eight copies of each chromosome (they’re octoploid), so there’s plenty of DNA to isolate.
Why do we use wheat germ to extract DNA?
The DNA in raw wheat germ is encased in the nucleus of the cell, and warm water (between 55 and 60 degrees Celsius) will deactivate a DNA-breaking enzyme in the cell.
What is the purpose of dishwashing liquid in DNA extraction?
Because the DNA molecules are dissolved in water, each individual DNA molecule is surrounded by water molecules, which is a very polar molecule, the dish soap pulls apart the membranes, releasing the DNA.
What 4 steps are needed to purify the DNA?
All DNA purification chemistries follow the same five basic steps for DNA extraction: 1) disrupting the cellular structure to create a lysate, 2) separating the soluble DNA from cell debris and other insoluble material, 3) binding the DNA of interest to a purification matrix, and 4) purification.
What are three reasons why scientists isolate DNA?
The ability to extract DNA is critical for research into the genetic causes of disease and the development of diagnostics and drugs, as well as forensic science, genome sequencing, detecting bacteria and viruses in the environment, and paternity determination.
Why do uneaten strawberries eventually rot?
Several types of fungus can infect strawberry plants, including the fruit, and this is more likely when the soil remains too moist, which promotes fungal growth. Botrytis fruit rot, for example, can lay dormant on your berries until they are nearly mature, and it causes the fruit to become squishy and fuzzy on the outside.
What fruits can you extract DNA from?
In this lab, DNA can be isolated and extracted from foods like strawberries, bananas, kiwis, raspberries, and onions, as well as meats, other produce, and even processed foods like corn chips and crackers.
Does human DNA look the same as strawberry DNA?
Yes, the DNA from both cell types will have the same structure because DNA is a double helix shaped molecule (composed of a sugar-phosphate backbone and paired nitrogenous bases) that condenses into chromosomes for packaging into cells.
Why can’t you extract DNA from toasted wheat germ?
When household products are applied to both toasted and untoasted wheat germ, DNA is not extracted from the toasted sample because the heat denatures the DNA, making it less visible.
What else could be used to extract DNA in place of the raw wheat germ?
Students will isolate DNA from raw wheat germ using dish soap, meat tenderizer, baking soda, and alcohol, as well as other common household chemicals.
How is germ removed from wheat?
Wheat germ is a by-product of the wheat milling industry, and it is separated from the endosperm during milling due to its unfavorable baking properties and the oil’s oxidation susceptibility.
What is the purpose of adding detergent to the solution?
By dissolving the cell’s lipids and proteins and disrupting the bonds that hold the cell membrane together, the detergent causes the cell membrane to break down, causing the lipids and proteins to precipitate out of solution.
Why is pineapple juice used in DNA extraction?
(In this experiment, pineapple and papaya juice perform the same function as meat tenderizer.) When DNA is packaged in the nucleus, it is wound tightly around proteins, which bromelain and papain enzymes break down, allowing the DNA to be released with minimal breakage.