A.
ifferences from Mitosis
1. Two processes distinguish meiosis from mitosis: crossing over through
synapsis and reduction division.
2. When homologous chromosomes come together during prophase I, they
associate with each other along their lengths, a process called synapsis.
During synapsis, sections of homologous chromosomes are physically
exchanged in crossing over, resulting in daughter cells that are not
genetically identical to the parent cell or to each other.
3. Meiosis also differs from mitosis in reduction division, in which the
daughter cells contain half the number of chromosomes as the parent
cell. Reduction division occurs because meiosis contains two nuclear
divisions but only one round of DNA replication during interphase.
4. The primary reasons for the differences in meiosis and mitosis stem from
the synapsis of homologous chromosomes in prophase I. The close
association of the homologous chromosomes in synapsis blocks the inner
centromeres from attaching to the spindle. As a result, sister chromatids
do not separate during meiosis I, resulting in reduction division.