Cell Division and Cellular Organisation Flashcards
what happens during prophase [5]
- chromosomes become visible as DNA coils condense
- Nucleolus denuclearises appears
- centrioles move apart to opposit poles of the cell
- spindle fibres form from microtubules
- nuclear membrane breaks down
what happens during metaphase [3]
- centrioles reach poles and spindle is complete
- chromosomes moved by spindle fibres to line up along the equator/metaphase plate of the cells w/ chromatids facing opposite poles
- mitotic spindle created
what happens during anaphase [3]
- centromeres holding chromatids divide
- microtubules from the spindle pull the chromatids apart
- they move to opposite poles
what happens during telophase [4]
- chromatids reach each pole & become the new chromosomes of the daughter cells
- microtubules making up the spindle break down
- nuclear envelope reforms
- chromosomes uncoil and become long and thin again
what is cytokenisis
- division of the cytoplasm
- a cell division stage in the mitotic phase of the cell cycle that results in the production of 2 identical daughter cells
what is the centromere
- region at which 2 chromatids are held together
what is are chromatids
- 2 identical copies of DNA held together at a centromere
what is chromatin
uncondensed and coiled DNA in a complex with histones
what is a cleavage furrow
- formed in around the middle of animal cells when the cell surface membrane is pulled inwards by the cytoskeleton until it is close enough to fuse around the middle and form 2 cells
what is the cell plate and how is it formed
- vesicles form the golgi apparatus begin to assemble in the same place where the metaphase plate was formed
- vesicles fuse with each other and the cell surface membrane, dividing the cell into 2
what is mitosis
cell division which forms 2 genetically identical daughter cells
what is mitosis used for
- growth and tissue repair
- asexual reproduction
name (in order starting after a division) the stages of the cell cycle
- Gap phase 1 (G1)
- Synthesis (S-Phase)
- Gap phase 2 (G2)
- Mitosis & cytokenisis
which phases occur during interphase
- G1
- S-phase
- G2
what are the three checkpoints
- G1 checkpoint
- G2 checkpoint
- Metaphase checkpoint
what happens in G1 checkpoint
the cell is checkedcto see that it divided correctly
what happens to a cell in G1 checkpoint if it is not okay
- the cell cycle stops and the cell goes through apoptosis
what happens in G2 checkpoint
- what happens if the DNA has mutations or is damaged
- cell checks if the DNA has been replicated properly
- cell cycle is stopped/DNA is repaired
what is checked in the metaphase checkpoint
- cell checks that chromosomes have attached to the spindle
