Cell Reproduction Meiosis Notes

Why does meiosis occur?

How does meiosis occur? Meiosis Two Nucleus Prophase Metaphase Anaphase Telophase DNA Interphase

Meiosis is divided into two division Meiosis I –Prophase I –Metaphase I –Anaphase I –Telophase I Meiosis II –Prophase II –Metaphase II –Anaphase II –Telophase II

Prophase I Chromatin Nuclear envelope Homologous Cross over

One Chromosome and it’s Copy

MOMDAD Homologous Chromosomes: paired chromosomes with genes for the same traits

Prophase I Chromosomes Nuclear envelope Homologous Cross over

Metaphase I Spindle Equator

Anaphase I Separate Spindle Fibers

Telophase I Cytoplasm (cytokinesis)

End of 1 st Division Result: 2 diploid cells each with 46 chromosomes

Prophase II Spindle chromosomes

Metaphase II Chromosomes Equator

Anaphase II centromeres

Telophase II Nuclear envelope Spindle Cell Cytokinesis Four Haploid

End of 2 nd Division Result: 4 haploid cells each with 23 chromosomes

Comparing Mitosis and Meiosis

MITOSISMEIOSIS Number of Divisions Number of Daughter Cells Genetically Identical? Chromosome # Where When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells Genetically Identical? Chromosome # Where When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical? Chromosome # Where When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical?Yes No Chromosome # Where When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical?Yes No Chromosome #46 23 Where When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical?Yes No Chromosome #46 23 Where Somatic (body) Cells Gametes (Sperm and Egg) When Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical?Yes No Chromosome #46 23 Where Somatic (body) Cells Gametes (Sperm and Egg) When Making new body cells Making reproductive cells Role

MITOSISMEIOSIS Number of Divisions1 2 Number of Daughter Cells2 4 Genetically Identical?Yes No Chromosome #46 23 Where Somatic (body) Cells Gametes (Sperm and Egg) When Making new body cells Making reproductive cells RoleGrowth and repair Reproduction

MITOSISMEIOSIS Occurs in ________ (body) cells Occurs only in ________ (sex organs:______/______) Produces cells for______, maintenance, ______, asexual reproduction) Only produces_______________ (sex cells:______/______) Results in _____ diploid (2n) daughter cells Reduction division results in _____________ (n) cells

MITOSISMEIOSIS Occurs in somatic (body) cells Occurs only in gametes (sex organs: testes/ovaries) Produces cells for______, maintenance, ______, asexual reproduction) Only produces_______________ (sex cells:______/______) Results in _____ diploid (2n) daughter cells Reduction division results in _____________ (n) cells

MITOSISMEIOSIS Occurs in somatic (body) cells Occurs only in reproductive organs (sex organs: testes/ovaries) Produces cells for growth, maintenance, repair, asexual reproduction) Only produces gametes (sex cells: sperm/egg) Results in _____ diploid (2n) daughter cells Reduction division results in _____________ (n) cells

MITOSISMEIOSIS Occurs in somatic (body) cells Occurs only in reproductive organs (sex organs: testes/ovaries) Produces cells for growth, maintenance, repair, asexual reproduction) Only produces gametes (sex cells: sperm/egg) Results in TWO diploid (2n) daughter cells Reduction division results in FOUR haploid (n) cells