1. Meiosis = cell division that reduces the number of chromosomes in half
Meiosis (p )
Meiosis = cell division that reduces the number of chromosomes in half
Diploid number to haploid number
Gametes = sex cells; have haploid number (male: sperm, female: egg)
Like a double mitosis: PMAT I and PMAT II, with some key differences
Diploid =
Haploid =

3. Prophase I = homologous chromosomes pair up
Meiosis (p )
Prophase I = homologous chromosomes pair up
Called synapsis; chromosome pairs called tetrads (tetra = 4)
Crossing-over = chromatids swap genes; happens sometimes causing genetic variation
Genetic recombination = new mix of genes from crossing-over

4. Metaphase I = tetrads line up along the equator
Meiosis (p )
Metaphase I = tetrads line up along the equator
Homologous pairs line up next to each other
Key difference

5. Anaphase I = homologous chromosomes move to opposite poles
Meiosis (p )
Anaphase I = homologous chromosomes move to opposite poles
Big difference: each chromosomes still has 2 chromatids
That is the centromeres don’t split

6. Meiosis (p )
Telophase I = 2 cells separate, but now each cell has haploid number of chromosomes

8. Single chromatid is not copied during an interphase stage
Meiosis (p )
PMAT II = looks very much like mitosis but at the end it has haploid number (1n)
Single chromatid is not copied during an interphase stage
Instead these gametes will match up chromatids when they fuse with another sex cell
Zygote = sperm and egg fused to form new cell again with diploid number (2n)

10. Offspring is genetically unique
Meiosis (p )
Sexual reproduction = reproduction by forming a zygote (male and female)
Offspring is genetically unique
Asexual reproduction = reproduction from one parent
By binary fission or mitosis only, no meiosis
Offspring is genetically identical to parent