A CIBT Lab Exercise in Molecular Biology
In this laboratory exercise, students stain a fixed preparation of human cancer cells that were cultured in the laboratory. The stained cells are observed microscopically; students will observe cells containing the classical "X" shaped chromatids at metaphase. Students gain microscope practice and collect interesting data about chromosome number and chromosome type. A karyotype of several well spread cells is prepared and compared to a karyotype of normal human cells. This activity can serve as a springboard to class discussions about genetic defects that can be diagnosed by the use of karyotyping.
Regents Biology, and AP Biology or equivalent.
One class period each of two days: Day one - stain the cells and prepare a permanent slide. Day two - observe the karyotypes and sketch the results.
Materials (per team of students):
- Pasteur pipette and bulb or a disposable pipette
- tape or marker to label slides
- microscope or the whole class
- cold methanol
- several chilled microscope slides, #1 glass coverslips, xylene to clean up excess Permount
- The karyotyping kit can be ordered from CellServ. The kit (CSK4) contains tubes of cells ready to stain, containers of Stain #1, Stain #2, and Permount. Be sure to order the kit several months ahead of time. The kits are prepared just before you need them and must be used within a week or two. When they arrive, the cells must be stored in the refrigerator. CellServ can be contacted through their web site at: www.cellserv.org.
Price: No Charge
Rita Calvo, Cornell University, Ithaca, NY
Mary Colvard, Cobleskill High School. Cobleskill, NY
Glenn Simpson, Victor High School, Victor, NY