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Diploid. Cells that contain TWO sets of chromosomes (2n) One set comes from the mother and one from the father Humans have a diploid number of 46. Haploid. Cells that contain ONE set of chromosomes (1n) Haploid cells are sex cells, or gametes Humans have a haploid number of 23.
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Diploid • Cells that contain TWO sets of chromosomes (2n) • One set comes from the mother and one from the father • Humans have a diploid number of 46
Haploid • Cells that contain ONE set of chromosomes (1n) • Haploid cells are sex cells, or gametes • Humans have a haploid number of 23
Mitosis vs. Meiosis • Mitosis is how a parent cell replicates to create TWO IDENTICAL DIPLOID daughter cells • Meiosis is how a parent cell divides to create FOUR UNIQUE HAPLOID daughter cells (for sex) • Names of steps of Mitosis and Meiosis are the same (Prophase, Metaphase, Anaphase, Telophase)
Meiosis I • First stage of meiosis • Number of chromosomes is divided in half • Variation occurs
Meiosis II • Second stage of meiosis • Exactly like mitosis • Chromosomes are already in pairs in Prophase II
What would happen if the chromosome number was not divided in half in meiosis? (Think about fertilization)
Prophase I • Homologous (same) chromosomes pair up • Chromosomes “cross-over” and exchange information
Metaphase I • Chromosomes pairs line up, one set on either side of the metaphase plate • In humans, one set of the 23 pairs of chromosomes are on one side, and the other set is on the other side
Metaphase II • Chromosomes line up in the middle of the cell, with one CHROMATID on each side
Meiosis Gigilo • Oh oh oh oh oh oh oh oh oh oh oh • I’m a chromosome, in the meiosis show. • You can tell by the four daughter cells oh oh • See how I’m startin with my diploid bros, • Always splitting to make haploids oh, • I’m a chromosome, in the prophase show. • Every time I pair up I cross over low, • Then leave my pair from the metaphase row, • Divide in half before the next stage OH!
Meiosis Flow Chart • Create a flow chart detailing the steps of Meiosis. Your flow chart must: • Be detailed and neat • Color • Blue and yellow chromosomes (one color/sister chromosome) • Green spindle fibers • Black cell membrane • Show all of the steps of Meiosis I and II • LABEL EACH CELL: • Diploid or Haploid number (1n, 2n) • Step of Meiosis
Exit Ticket: Identify the step of Meiosis for each of the following pictures • 1. 2. 3. • 4. 5. 6.