cell division Flashcards
(25 cards)
what cells does mitosis produce?
2 genetically identical diploid daughter cells
what cells does meiosis produce?
4 non identical haploid daughter cells (gametes)
what type of reproduction does mitosis occur?
asexual reproduction
> for growth, repair and formation of new cells
what type of reproduction does meiosis occur?
sexual reproduction
> to produce haploid sex cells
what is a diploid?
where both cells have 23 pairs chromosomes
what is a haploid?
each cells has half the number of a body cell
what 2 phases is the cell cycle split into?
interphase and mitosis
what type of cells cannot be divided?
specialised cells
what phase does the cell majority spend? give the percentage.
interphase
- 90%
what phases is interphase split into?
G1 –> S phase (synthesis) –> G3
what occurs within interphase?
- where DNA is replicated (doubled) so each cell has the same amount of DNA
- DNA is uncondensed
- organelles are replicated
- ATP is increased to produce enough energy for cell division
what occurs in the G1 phase in interphase?
the cell elongates and new organelles and proteins are made
what occurs in the S phase in interphase?
cell replicates the DNA (DNA replication)
what occurs in the G2 phase in interphase?
cell keeps elongating and proteins are produced which is needed in cell division
what is mitosis?
a phase within the cell cycle which is the formation of new identical daughter cells
what occurs in cytokinesis?
where cytoplasm and cell membrane divides to form genetically identical daughter cells for cell cycle to occur again.
what are sister chromatids?
two strands within a chromosome
what is a centromere?
the ‘centre’ of a chromosome
> where the chromatids are joined
why are the chromosomes not visible during interphase?
as DNA is uncondensed.
> the nucleolus is visible and nuclear envelope
what are the stages of mitosis?
P.M.A.T
> prophase
> metaphase
> anaphase
> telophase
what occurs during prophase?
- chromosomes condense and become visible
> the nucleolus disappears
> nuclear envelope disintegrates - centrioles moves to the poles of the cell and produces spindle fibres
what occurs during metaphase?
- nuclear membrane disappeared
- spindle fibres have attached to centromere
- chromosomes are pulled to the equator of the cell and line up
what occurs during anaphase?
- spindle fibres contract
- centromere splits in half
- each chromatid is pulled to opposite poles of cell
whar occurs during telophase?
- nuclear envelope reforms
- spindle fibres disappear
- chromosomes uncoil
- cytoplasm begins to divide to form new genetically identical cells
> 1/2 amount of DNA compared to interphase cell
