When three copies of a specific chromosome are present in a cell, this is called Blank______Multiple choice question.karyosomytrisomytrichromosomymonosomy

The correct answer to the question is "trisomy."

Explanation:

1. Definition of Trisomy: Trisomy refers to the condition in which there are three copies of a specific chromosome in a cell instead of the usual two. This is a type of aneuploidy, which is an abnormal number of chromosomes in a cell.

2. Context of Chromosomes: In humans, for instance, a normal somatic (body) cell contains 46 chromosomes, arranged in 23 pairs. When a cell has an additional copy of a chromosome, such as in Down syndrome (trisomy 21), it results in 47 chromosomes in total—three copies of chromosome 21.

3. Comparison with Other Terms:

   • Karyosomy: This term is not widely used in cytogenetics and does not specifically describe chromosome numbers.
   • Trichromosome: This is not a standard term used in genetics.
   • Monosomy: This refers to the presence of only one copy of a chromosome instead of two, which is the opposite of trisomy.

Understanding these distinctions is essential in genetics, as conditions related to chromosome number variations can lead to different genetic disorders. Thus, when we encounter the term with three copies of a specific chromosome, it is clear that this is classified as "trisomy."