mitosis & meiosis

cell cycle

eukaryotes

mitosis and meiosis

s phase → g2 → division → g1 (interphase)

g1: diploid (2n)

synthesis: duplication stage, still 2n = 4 b/c u count the centromeres, sister chromatids, and homologous pairs made

mitosis: identical copy (haploid → haploid & diploid → diploid), separates the sister chromatids

meiosis; reduction division (diploid → haploid), separates the homologous pairs

mitosis

prophase: preparation; chromatin condenses (supercoiling); nuclear membrane disassociates, asters form and migrate to the poles, 2n=4

metaphase: chromosomes line up such that sister chromatids are separated; kinetochore microtubules attach to the kinetochore, non kinetochore microtubules span the cell and elongate the cell by pushing the asters apart

anaphase: kinetochore microtubules shorten; non-kinetochore microtubules elongate, pushing the poles apart

telophase/cytokinesis: chromatin unwinds, nuclear membrane reforms, asters disappear, cell membrane pinches inward in animals and the cell plate forms in plants

meiosis

prophase one: chromatin condenses (supercoiling); nuclear membrane disassociates; asters form and migrate to the poles

metaphase one: chromosomes line up such that homologous pairs are separates, kinetochore microtubules attach to the kinetochore, non-kinetochores span the cell

anaphase one: kinetochore microtubules shorten, non-kinetochore microtubules elongate and pushes the poles apart

telophase/cytokinesis one: chromatin unwinds, nuclear membrane reforms, asters disappear, cell membrane pinches inward for animals and the cell plate forms for plants

prophase two:

metaphase two

anaphase two

telophase two: telophase one happens twice

sexual reproduction (life cycle)

2n diploid → meosis → gametes (haploid) → fertilization → zygote (2n) - → mitotsis

plants (plantae)

life cycle: alternation of generations (diploid individuals → haploid individuals)

sporophyte: diploid individual, 2n, produces spores (n) used during meiosis to make spores

sporophyte (2n) → meiosis → spores → mitosis

s → gametophyte (n) → mitosis → gametes (n) → mitosis