Final answer:
Cells are exposed to a hypotonic solution during karyotyping to induce swelling, which separates chromosomes and allows for clearer imaging and more accurate analysis of genetic conditions.
Step-by-step explanation:
It is necessary to expose cells in a hypotonic solution for karyotyping to obtain clear chromosome images. In a hypotonic solution, water particles move into the cell causing them to swell. This is crucial during karyotyping because, after the application of colchicine, which arrests cells in metaphase with condensed chromosomes, the swelling of cells due to the hypotonic solution helps the chromosomes spread out and prevents overlapping, thereby allowing for easier observation and more accurate chromosome counting and analysis. For human cells, this process is essential to identifying and diagnosing various genetic conditions and abnormalities.