Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What term describes half of a pair of chromosomes in sex cells?

1. Diploid

2. Haploid

3. Chromatid

4. Chromosome

The correct answer is: Haploid

The term that describes half of a pair of chromosomes in sex cells is haploid. In the context of sexual reproduction, gametes (sperm and egg cells) are produced through a process called meiosis, which reduces the chromosome number by half. This means that each sex cell contains one copy of each chromosome, which is referred to as haploid. In contrast, somatic cells, which make up most of the body, contain two sets of chromosomes (one from each parent) and are termed diploid. A chromatid, on the other hand, is one-half of a duplicated chromosome, and it becomes relevant during cell division, particularly in the context of mitosis and meiosis when chromosomes are replicated. A chromosome itself is a structure made up of DNA and proteins that contains genetic information; it can exist in a duplicated or unduplicated state. Thus, haploid specifically refers to the condition of having only one complete set of chromosomes, which appropriately describes the content of sex cells.