QUESTION SET ACCURATE ANSWERS
◉ Metaphase.
Answer: 46 chromosomes line up at the equator of the cell.
◉ Anaphase.
Answer: -As the spindle microtubules shorten, the kinetochores are
pulled away from each other, causing separation of centromeres,
which results in the separation of the chromatids
-46 chromatids migrate to each pole
-Cytokinesis begins
◉ Telophase.
Answer: -Chromosomes de-condense to chromatin
-Nucleoli and nuclear envelope reappear
-Spindle disassembles
-Cytokinesis ends (or may end after telophase ends)
◉ Meiosis.
Answer: -"Reproductive nuclear division"
-Produces gametes (ovum and sperm)
,-Involves interphase followed by two cell divisions: Meiosis I
immediately followed by Meiosis II
-Interkinesis occurs between meiosis I and II, NOT interphase (no
DNA replication)
◉ Meiosis: Similarities to Mitosis.
Answer: 1. Prophase I, II
-Chromosomes condense
-Nuclear envelope, nucleoli disappear
-Spindle apparatus forms
-Kinetochore microtubules capture chromosomes
2. Anaphase I, II
-Cytokinesis begins
3. Telophase I, II
-Chromosomes de-condense to chromatin
-Nuclear envelope, nucleoli reappear
-Spindle disassembles
-Cytokinesis continues--may end after telophase ends
◉ Meiosis I: Differences to Mitosis.
, Answer: Reduction division (2n to n)--
a) Prophase I: Homologous chromosomes attach together as tetrads
(4 Xms in a row) and crossing over occurs.
b) Metaphase I: 23 tetrads line up along the cell equator.
c) Anaphase I: Tetrads separate and migrate to opposite poles, i.e. 1
homologous chromosome (with 2 sister chromatids) goes to each
pole--chromatids DON'T separate.
d) Telophase I: After meiosis I and cytokinesis ends, each cell has 23
different chromosomes (n). These cells DO NOT have homologous
chromosomes. The chromosomes (1-23) can be from either the
Mom OR the Dad (randomly segregated).
◉ Crossing Over.
Answer: The piece of one chromatid exchanges with a matching
piece from a chromatid of the homologous chromosome, i..e. non-
sister chromatid. This acts to increase genetic variety.
Ex. You pass on your Dad's black hair with your Mom's blue eyes.
◉ Meiosis II: Differences to Mitosis.
Answer: Same as mitosis except with 23 chromosomes instead of 46
--> 23 chromosomes line up at the equator in metaphase II and 23