Meiosis
- Interphase
2.Meiosis 1
3.Meiosis 2
S phase
G2
G1
cell gets larger
organelles being duplicated
Proteins and enzymes are made
DNA copies itself
makes sister chromatids
centrioles are duplicated
cell grows even more
makes more protiens and enzymes
centrioles start organizing microtubules
Metaphase 1
Anaphase 1
Prometaphase 1
Telophase 1
Prophase 1
Cytokinesis 1
Metaphase 2
Prometaphase 2
Anaphase 2
Telophase 2
Prophase 2
Cytokinesis 2
chiasmata form between the sister chromatids within the tetrad
crossing over happens at chiasmata
chromosome pair bond along the length witch forms tetrads (Tetris) (length bc its easier to switch sister chromatids)
chromosome condenses
DNA chromatin condenses into chromosomes
hardest step first
nucleus dissolves
centrioles start making microtubules into spindles and attaching them to homologous pairs at the kinetichore
with the help of centromeres and spindle microtubules, homologous pairs line up at the metaphase plate
cell membrane dissolves
spindle microtubules shorten and separate homologous pairs
centrioles with the sister chromatids still attached to them are pulled apart to opposite ends of the cell
maternal and paternal homologous pairs are separated from the microtubules
spindle microtubules separate the two new haploid cells
each cell contains 3 chromosomes from each homologous pair
nuclei form around separated chromosomes
chromosomes uncondensed
cell membrane forms
chromosomes arrive at opposite sides of the pole
in some organisms, nuclear membrane reforms and the chromosome condenses but in others, this step is skipped
occurs at the same time as telophase 1
two haploid cells are formed
the two new daughter cells pinch off and separate from each other at the cleavage furrow
centrosome starts making microtubules into spindles and attached them to the sister chromatids at the kinetochore
nuclear envelope breaks down if needed
centromeres move apart
starting cells are haploid made in meiosis 1
spindle form and spindle microtubules begin to catch chromosomes
DNA condenses to chromsomes
the nucleus dissolves
chromosomes line up individually
spindle microtubules shorten and separated sister chromatids
individual chromosomes are pulled to opposite ends of the cell
nuclei form around separated chromosomes
each cell is now an individual unique gamete
chromosomes condense
and cell membrane dissolves
spindle microtubules begin separating the 4 new haploid cells
splits the chromosome sets into new cells
final product of meiosis
four haploid cells
in humans, product is sperm or egg cells
the four new daughter gametes pinch off and separate from each other at the cleavage furrow
with the help of the centromeres and spindle microtubules sister chromatids line up at the metaphase
cell membrane dissolves