Final answer:
A scientist that studies chromosomal compositions is called a cytologist, who works alongside geneticists to observe karyotypes and diagnose genetic disorders.
Step-by-step explanation:
A scientist who examines the chromosomal composition of a particular cell is called a cytologist. This professional specializes in the study of cells, including the detailed observation of chromosomes to detect any abnormalities. To observe an individual's karyotype, a geneticist collects cells, such as white blood cells from a blood sample, and undertakes several steps in the laboratory.
These steps include stimulating the cells to divide, arresting chromosome movement in metaphase with chemicals, causing cells to swell with a hypotonic solution, and preparing the cells on a slide to create a karyogram. By closely examining the karyogram, the geneticist identifies chromosomal characteristics such as size, banding pattern, and centromere position which are essential in diagnosing genetic disorders.