Page 1:

• Purpose of meiosis:

  • To make gametes (egg and sperm cells)

  • Only body cells go through meiosis

  • Daughter cells have half the amount of DNA

• Chromosomes:

  • Each person has 1 chromosome set from mom and 1 set from dad

  • Egg/sperm cells need only 1 set each

• End result of meiosis:

  • Meiosis ends with genetically different cells

  • You resemble your siblings but are not identical to them

Page 2:

• Phases of meiosis:

  • Interphase: Growth and DNA duplication

  • Prophase I: Nuclear membrane breaks down, chromosomes find their homologous pair, crossing-over can occur

  • Metaphase I: Homologous chromosomes line up in the middle, spindle fibers attach to the center of each chromosome

• Anaphase I: Homologous pairs get pulled to opposite poles, separate the homologous pairs from each other

• Telophase I / Cytokinesis: Nuclear membrane reforms, cells separate into two, only have half the number of chromosomes it started with

• Prophase II: Nuclear membrane breakdowns in each cell, centrioles and spindle fibers reform

• Metaphase II: Chromosomes line up in the middle, spindle attaches to centromeres

• Anaphase II: Sister chromatids separate

• Telophase II / Cytokinesis: Nuclear membrane reforms, cell divides and separates into four cells

Page 3:

• End results of meiosis:

  • Cells at the end of meiosis are not identical

• Centrosome, Interphase, chromosome, Prophase I, X, Recombination, Metaphase I, Anaphase I, Telophase I & Cytokinesis, Prophase II, Metaphase II, Anaphase II, Telophase II & Cytokinesis, Four granddaughter cells, n - haploid, 2n - diploid

Page 4:

• Mitosis:

  • Purpose: Grow and repair cells

  • Ending cells: 2 identical, diploid cells

• Meiosis:

  • Purpose: Make gametes

  • Ending cells: 4 non-identical, haploid cells

Page 5:

• Centrosome, Interphase, chromosome, 2n, DNA is copied, Prophase I, X, Recombination occurs, Metaphase I, Chromosomes line up at equator, meiotic spindle, Anaphase I, Chromosomes pulled apart, Telophase I & Cytokinesis, Cell pinches in the middle, Prophase II, Two daughter cells, Metaphase II, Chromosomes line up at equator, Anaphase II, Sister chromatids pulled apart, Telophase II & Cytokinesis, Cell pinches in the middle, Four granddaughter cells, n - haploid, 2n - diploid

Page 6:

• Mitosis:

  • Purpose: Grow and repair cells

  • Ending cells: 2 identical, diploid cells

• Meiosis:

  • Purpose: Make gametes

  • Ending cells: 4 non-identical, haploid cells

• Homologous Chromosomes:

  • Pair of maternal and paternal chromosomes that are similar in shape and size

  • Carry genes controlling the same inherited traits

• Chromosome Number Errors:

  • Monosomy: Having one copy of a chromosome instead of two

  • Trisomy: Having three copies of a chromosome instead of two

  • Polyploidy: Having multiple copies of multiple chromosomes

Page 7:

• Centromere Position:

  • Metacentric: Middle of the chromosome

  • Submetacentric: Between the center and end of the chromosome

  • Acrocentric: Near the end of the chromosome

• Karyotypes:

  • Image of chromosomes from a diploid cell in which they are counted and matched

  • Distinguished by chromosome length, centromere position, and banding pattern

• Nondisjunction:

  • When a pair of homologous chromosomes have failed to separate at anaphase

  • Results in both chromosomes of the pair passing to the same daughter cell

Page 8:

• Chromosome structure errors:

  • Deletion: Part of a chromosome breaks off and attaches to a different chromosome

  • Inversion: Section of a chromosome breaks off and reattaches upside-down on the same chromosome

  • Duplication: Section of a chromosome is repeated

• Chromosomal Disorders:

  • Down Syndrome: Also called trisomy 21, caused by an extra copy of chromosome 21, symptoms include intellectual disability and characteristic facial features

  • Patau Syndrome: Also called trisomy 13, caused by an extra copy of chromosome 13, symptoms include severe intellectual disability and physical abnormalities

• Translocation, Inversion, deletions, duplication

Page 9:

• Klinefelter Syndrome: where boys are born with an extra X chromosome