Unit 10 - Meiosis From Egg to Embryo – This photograph shows the After the egg [shown in orange] is released from the ovary, it travels into the fallopian tube. It stays there until a single sperm [shown in blue] fertilizes it. This unit will explain the process of meiosis in the production of eggs and sperm; summary color is blue and vocabulary words are underlined .
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From Egg to Embryo From Egg to Embryo – This photograph shows the After the egg [shown in orange] is released from the ovary, it travels into the fallopian.
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Unit 10 - Meiosis
From Egg to Embryo – This photograph shows the After the
egg [shown in orange] is released from the ovary, it
travels into the fallopian tube. It stays there until a single sperm [shown in blue] fertilizes it. This
unit will explain the process of meiosis in the production of
eggs and sperm; summary color is blue and vocabulary words
Meiosis I The stages of meiosis I are identical to the stages of
cell cycle and mitosis; there are only slight differences during prophase.
After going through the steps of Meiosis I 1. Interphase 12. Prophase 1 [+ crossing over]3. Metaphase 14. Anaphase 15. Telophase 1 + Cytokinesis Forms 2 diploid daughter cells. …the cell divides again! [AKA Meiosis II]
"Meiosis." Biology. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010.Science in Context. Web. 3 Dec. 2013.
Homologous Chromosomes
AKA homologs are paired Xsomes with genes of the same trait in the same order; within each pair, one chromosome comes from each parent. Homologous chromosomes
are only found in a diploid cell.
"Result of Crossing Over." Genetics. Ed. Richard Robinson. New York: Macmillan Reference USA, 2010. Science in Context. Web. 3 Dec. 2013.
Homologs in a Karyotype
This a karyotype, a tool that geneticists use to look for mutations.
It groups the homologous chromosomes in pairs; the longest pair is #1, the shortest pair is #22.
"Mitosis and meiosis." World of Anatomy and Physiology. Gale, 2010. Science in Context. Web. 4 Dec. 2013.
Name & Period at the Top
What are the similarities and
differences between the processes of
mitosis and meiosis?
List your answer in bullet points on
your sticky note.
Visualizing the Process Use the play dough and
the chalk to show meiosis at your tables. Our organism only has 2
chromosomes; use two colors [do not completely mix them].
Show the following: Meiosis 1 Stages Crossing over Meiosis 2 Stages +
Cytokinesis Label the following:
Diploid cell Haploid cell
Knowledge Check
How many chromosomes are at the beginning of the diagram versus at
the end? Based on that information, how many would go in each haploid daughter cell? Turn and talk to your
neighbor.
Nondisjunction
During meiosis, if homologous chromosomes fail to separate correctly during anaphase (nondisjunction) then gametes have either extra Xsomes or they are missing chromosomes. These mutations are passed on during fertilization
[see image to the right]. Offspring with more than the usual #
of Xsomes are called polyploids. ▪ Rare in animals, sometimes causes death. ▪ Common in plants; polypoids are often healthier.
Example of Polyploidy
One of the most common examples of polyploidy in humans is Trisomy
21 [extra copy of chromosome 21]. These individuals have Down