Kaplan Nursing Entrance Practice Exam

Which process cannot occur in haploid cells?

1. Mitosis

2. Meiosis

3. Fertilization

4. Cell division

The correct answer is: Meiosis

Meiosis is the process that cannot occur in haploid cells because meiosis is specifically designed to reduce the chromosome number in diploid cells to generate haploid gametes. In organisms that undergo sexual reproduction, meiosis takes a diploid cell (which contains two sets of chromosomes) and divides it through two rounds of division to produce four non-identical haploid cells. This haploid state is crucial for sexual reproduction, where two gametes (from two different individuals) will ultimately fuse during fertilization to restore the diploid chromosome number. In contrast, processes such as mitosis, fertilization, and general cell division can occur in haploid cells. Mitosis can happen in haploid cells as they are capable of duplicating and dividing their contents to produce two genetically identical haploid daughter cells. Fertilization involves the merging of two haploid cells, usually in the form of sperm and egg, to create a diploid zygote. Thus, even though haploids can undergo cell division, meiosis is inherently linked to diploid cells as a means of producing gametes.