During meiosis, the “chiasma” is the point of chromatid contact that precedes crossing over. The crossing over event then occurs at this point. Synapsis refers to the pairing of homologs during prophase I of meiosis.

During the anaphase I stage of meiosis, homologous chromosome pairs separate to opposite poles of the cell, and the cell elongates. The sister chromatids remain attached at the centromeres. This maintenance of sister chromatids is the key difference between meiosis and mitosis. In mitosis, anaphase features the separation of sister chromatids, which is what will happen during anaphase II of meiosis. Note however, that the sister chromatids in meiosis are not identical, due to crossing over in prophase I. 

Meiosis is the process that forms haploid gametes, or sex cells, that will go on to form zygotes after fertilization. Meiosis is performed by germ line cells, which, in humans, are located in the gonads (ovaries of females and in the testicles of males).

Meiosis produces four daughter cells that are haploid, meaning that they contain half the number of chromosomes as the parent cell. Human parent somatic cells have 46 chromosomes, or 23 chromosome pairs, meaning that gametes produced during meiosis have 23 chromosomes.

Synapsis is the pairing of homologous chromosomes during prophase I of meiosis. Due to synapsis, pairs of homologous chromosomes are arranged in a way that allows for crossing over to occur, which leads to genetic recombination, and genetic diversity.

Meiosis I is the first cell division of the entire meiosis process. Following segregation of homologous chromosome pairs, or tetrads, the two resulting daughter cells have half the number of chromosomes as the parent cell. These chromosomes have two sister chromatids per chromosome, which are nonidentical due to crossing over.

Prophase II marks the beginning of the second cell division of meiosis, called meiosis II. Unlike prophase I, the chromosomes are not duplicated prior to the start of prophase II. However, during prophase II, the centrioles replicate, resulting in two pairs of centrioles per cell. The two centriole pairs separate to opposite cell poles. Other features of prophase II are chromosome condensation, the degradation of the nuclear membrane, and meiotic spindle formation.

During metaphase II, sister chromosomes line up at the metaphase plate, like during the metaphase of mitosis. Mitotic spindles are attached to the kinetochores during this stage. Homologous chromosomes have already been separated during anaphase I.

Gametes are haploid sex cells produced from germ line cells during mitosis. During human fertilization, male and female haploid gametes fuse to form a diploid zygote. 

The processes of mitosis and meiosis have many characteristics in common (i.e. cytokinesis, chromosome condensation, and nuclear membrane reformation); however, there are key differences that distinguish the processes from one another. One of these differences is the cell type that result from each respective process. Mitosis results in two daughter cells with the same number of chromosomes as the parent cell. Meiosis, on the other hand, yields four daughter cells with half of the number of chromosomes as the parent cell—“haploid” cells.