Mitosis 2.1.6 (c,d,e) Flashcards
what is mitosis and what does it produce?
the nuclear division of cells to produce 2 genetically identical diploid daughter cells
how similar are the daughter cells produced in mitosis to the parents?
- they have the exact same copy of DNA
- they have the same number of chromosmes
why is mitosis necessary?
growth of multicellular organisms
repair and replacement of damaged tissues
asexual reproduction
structure of a chromosome at beginning of mitosis
two chromatids bound together at the centromere
what are the four stages of mitosis?
prophase
metaphase
anaphase
telophase
what happens during prophase?
the chromatin coils and condenses into chromosomes
the nuclear membrane breaks down
centrioles move to opposite poles of the cell
what happens during metaphase?
the spindle fibres attached to the centromeres of the chromosomes move them to the metaphase plate
what happens during anaphase?
the spindle fibres contract to pull the sister chromatids apart to opposite ends of the cell
cytokenesis begins
what happens during telophase?
the chromatids reach the opposite poles
they uncoil to form long single stranded chromosomes
the nuclear membrane reforms and cytokinesis continues
structure of chromosomes after mitosis
single stranded chromosomes
outline cytokinesis in animal cells?
a cleavage furrow forms in the middle of the cell and the cell surface membrane is pulled towards the centre by the cytoskeleton
the cell membrane fuses together to leave two separate cells
outline cytokinesis in plants
as plants have cell walls, a cleavage burrow cannot form
vesicles are secreted by the Golgi complex which then assemble at the metaphase plate to divide the two cells and form a new cell surface membrane
when does cytokinesis begin?
in anaphase
