Final answer:
The arms of a chromosome are designated as short or long. The short arm is abbreviated as p and the long arm is abbreviated as q.
Step-by-step explanation:
In a human karyotype, the arms of a chromosome are designated as short or long. The short arm is abbreviated as p, which stands for "petite", and the long arm is abbreviated as q. Each arm is further subdivided and denoted by a number. For example, locus 3 on the short arm of chromosome 21 is denoted as 21p3.