The chromosomes of the two cells then separate and pass into four daughter cells. The same demarcating phases of mitosis take place in meiosis I and meiosis II-prophase, metaphase, anaphase, and telophase-but with some variations contained therein.Īs shown in Figure 8-1, first, the chromosomes of a cell are divided into two cells. During meiosis II, those two cells each divide again. During meiosis I, a single cell divides into two. Two major phases of meiosis occur: meiosis I and meiosis II.
#Prophase 2 meiosis series
Meiosis occurs by a series of steps that resemble the steps of mitosis. In human cells undergoing meiosis, for instance, a cell containing 46 chromosomes yields four cells, each with 23 chromosomes. In meiosis, a cell containing the diploid number of chromosomes is converted into four cells, each having the haploid number of chromosomes. The process by which the chromosome number is halved during gamete formation is meiosis. Mitosis then brings about the development of the diploid cell into a multicellular organism. When the human gametes unite with one another, the original diploid condition of 46 chromosomes is reestablished. The gametes of human cells are haploid, from the Greek haplos, meaning “single.” This term implies that each gamete contains half of the 46 chromosomes-23 chromosomes in humans. In this situation, each sex cell is a gamete. Hence, human cells are diploid in that they have a pair of 23 individual chromosomes.ĭuring sexual reproduction, the sex cells of parent organisms unite with one another and form a fertilized egg cell (zygote). In human cells, for example, 46 chromosomes are organized in 23 pairs. The term diploid is derived from the Greek diplos, meaning “double” or “two” the term implies that the cells of plants and animals have pairs of chromosomes. Introduction to Nutrition and Digestion.Vascular Plants: Structure and Function.Quiz Domains and Kingdoms of Living Things.Quiz Structure of Prokaryote and Eukaryote Cells.The Structure of Prokaryote and Eukaryote Cells.Quiz Movement through the Plasma Membrane.
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