Edited Invalid date
10.3 The Phases of Meiosis
Take a look at how many combinations of chromosomes are possible in a cell.
Meiosis consists of two separate cell divisions.
The S phase of the cell cycle is where the replicated DNA is found.
There are prophase, metaphase, anaphase, and telophase in meiosis I and II.
During meiosis I, crossing-over occurs as a result of the exchange of color.
Two pairs of chromosomes separate during meiosis I and become haploid daughter chromosomes.
Each of the homologous chromosomes has been replicated during the S phase of the cell cycle.
Bivalents are formed by the synapsis of the homologous chromosomes.
There is a chance that crossingover may occur between the nonsister chromatids.
The genetic diversity of the daughter cells increases after crossing-over because the sister chromatids are no longer the same.
By the time prophase I is over, the homologous chromosomes will have the appearance of compacted metaphase chromosomes.
The alignment of the bivalents at the metaphase plate is what characterizes Metaphase I.
The two kinetochores of a duplicated chromosome are attached to the same kinetochore fiber.
Bivalents align themselves at the metaphase plate.
The maternal or paternal homologue of each bivalent may be oriented towards either pole of the cell.
The orientation of one bivalent is not dependent on the other bivalents.
All possible combinations of chromosomes can occur in the daughter cells, which is why this independent assortment of chromosomes contributes to the genetic variability.
The sister chromatids do not separate during anaphase I.
The number of chromosomes is reduced from 2n to n.
During meiosis, completion of telophase I is not required.
This phase may or may not be accompanied by cytokinesis, which is the separation of the cytoplasm.
The cells exiting telophase I are haploid.
After telophase, the cells enter interkinesis, a short rest period before the second nuclear division, meiosis II.
The process of interkinesis is similar to the process of interphase, except that the chromosomes are already duplicated.
The haploid number of chromosomes is found in the two daughter cells at the beginning of meiosis II.
There are duplicated sister chromatids on these chromosomes at this point.
In meiosis I, the chromosomes align at the metaphase plate, but they don't align in homologous pairs because only one of each pair is present.
The alignment of the chromosomes at the metaphase plate is similar to what is observed during a disease.
During meiosis II, sister chromatids separate and become daughter chromosomes.
There are four haploid daughter cells.
During anaphase II, the sister chromatids separate and become daughter chromosomes that are not duplicated.
The poles have daughter chromosomes moving toward them.
There are four haploid cells at the end of telophase II.
Review flashcards and saved quizzes
Getting your flashcards
Privacy & Terms