Zusammenfassung der Ressource
Mitosis
- Chromosomes
- DNA wound
tightly around
proteins called
histone
- Normally unwound
(Chromatin)
- Before cell division,
replicates and winds to
form chromosomes
(visible)
- Twice the DNA
- Made of two structures
called CHROMATIDS held
by a CENTROMERE
- Prophase
- Chromosomes visible as
they thicken and shorten
- Two identical chromatids
- Animal cells: centrioles divide
and move to opposite poles
- Start to form
spindle
- Nuclear membrane
disintegrates
- Nucleolus disappears
- Metaphase
- Chromosomes arrange at
the equator
- Chromosomes attached
to spindle by centromere
- Anaphase
- Spindle fibres contract
- Centromeres split so
chromatids pulled apart
- Separate chromatids now
called CHROMOSOMES
- Very fast
- Telophase
- Chromosomes reach poles
- Chromosomes
uncoil and lengthen
- Spindle
breaks down
- Nuclear membranes
reforms
- Nucleoli
reappears
- Cytokinesis
- Centrioles
divide and move
to poles
- Membrane furrows
and cytoplasm splits
- Daughter cells have all
organelles needed
- Significance
- Growth
- Repair damaged tissue
- Cell replacement
- Asexual repoduction
- Bulbs
- Large number of
offspring for colonisation
- Produces
- 4 genetically
identical
daughter cells
- Diploid