Fish that has been defrosted in the refrigerator will last for 1 to 2 days if kept in the refrigerator. If the fish is not cooked within 1 to 2 days, it can be safely refrozen. The safest way to defrost fish is in the refrigerator. Depending on the size of the filet, it may take a day or more to thaw completely. Once thawed in this manner, it is safe to leave the fish for a day or two in the refrigerator before cooking. Another safe way to thaw fish is via cold water thawing. While it is faster than defrosting in the refrigerator, it does require a bit more attention on the chef's part. First, be sure the filet is in an airtight plastic bag.
Scientists study DNA for many reasons: They can figure out how the instructions stored in DNA help your body to function properly. They can use DNA to make new medicines or genetically modify crops to be resistant to insects. They can solve who is a suspect of a crime, and can even use ancient DNA to reconstruct evolutionary histories! To get the DNA from a cell, scientists typically rely on one of many DNA extraction kits available from biotechnology companies. During a DNA extraction, a detergent will cause the cell to pop open, or lyse, so that the DNA is released into solution. Then alcohol added to the solution causes the DNA to precipitate out. In this activity, strawberries will be used because each strawberry cell has eight copies of the genome, giving them a lot of DNA per cell.
Gel extraction. In molecular biology, gel extraction or gel isolation is a technique used to isolate a desired fragment of intact DNA from an agarose gel following agarose gel electrophoresis. After extraction, fragments of interest can be mixed, precipitated, and enzymatically ligated together in several simple steps. This process, usually performed on plasmids, is the basis for rudimentary genetic engineering. After DNA samples are run on an agarose gel, extraction involves four basic steps: identifying the f