AC-HPAT Biology Practice Exam

Trisomy is characterized by the presence of three copies of a particular chromosome instead of the usual two. This condition occurs due to an error in cell division known as nondisjunction, where chromosomes fail to separate properly during meiosis or mitosis. As a result, an individual may have an extra chromosome, leading to various developmental and health issues depending on which chromosome is affected.

Common examples of trisomy include Down syndrome, which is caused by an extra copy of chromosome 21, and other conditions associated with trisomy of different chromosomes. The presence of this additional chromosome alters the typical genetic balance in the organism, affecting physical and cognitive traits.

Understanding the nature of trisomy provides insight into the genetic complexities and potential health implications associated with chromosomal abnormalities.