CELL DIVISION
Importance of cell division:
• Allow organism to grow
• Repairs/replaces damaged and dead cells/tissue
• Reproduction in some simple organisms
I [PMAT] C
Mitosis
INTERPHASE - cell still looks normal
- cell grows and builds up energy
- organelle number Increases
- cell either becomes specialised or prepares for mitosis
- DNA replication occurs
PROPHASE
1: nuclear membrane + nucleolus disappear
2: chromatin becomes tightly coiled - form chromosomes
3: chromosomes are double stranded [made of 2 chromatids]
4: chromatids are held together by a centromere
5: centrioles move to oppositee poles, with spindle fibers stretching between
them
METAPHASE
1: centrioles reach the oppositee poles with the spindle fibers in between
them
2: double stranded chromosomes line up at the equator in the middle of
the cell
, 3: each chromosome Is attached to a separate spindle fiber at the
centromere
ANAPHASE
1: spindle fibers pull apart the pair of identical chromatids
2: centromeres attaching chromatids split In half
3: one chromatid from each side is carried to the oppositee poles
4: single chromatid is one called a chromosome
TELOPHASE
1: daughter chromosomes reach the poles
2: new nuclear membranes surround the chromosomes, forming two nuclei
3: nucleoli reappear
4: chromosomes reappear less condense (unwind) forming chromatin
network identical to the original
5: an invagination starts to form in the middle of the cell
-> end of MITOSIS
CYTOKYNESIS - division of the cytoplasm
1: sharing of the cytoplasm and organelles occurs between two daughter
cells
2: cell membrane grows inwards the middle of the cell until it meets the
center, forming two Identical daughter cells
3: the cell plate grows across the cell and forms a new cell wall between the
two Identical daughter cells
4: the two cells separate and lead their own lives
* cell plate = plant cells
* furrow = animal cells
Where does mitosis take place?
In somatic cells (body cells)
Does not take place in the sex cells (sperm and egg cells)
-> gametes
Importance of cell division:
• Allow organism to grow
• Repairs/replaces damaged and dead cells/tissue
• Reproduction in some simple organisms
I [PMAT] C
Mitosis
INTERPHASE - cell still looks normal
- cell grows and builds up energy
- organelle number Increases
- cell either becomes specialised or prepares for mitosis
- DNA replication occurs
PROPHASE
1: nuclear membrane + nucleolus disappear
2: chromatin becomes tightly coiled - form chromosomes
3: chromosomes are double stranded [made of 2 chromatids]
4: chromatids are held together by a centromere
5: centrioles move to oppositee poles, with spindle fibers stretching between
them
METAPHASE
1: centrioles reach the oppositee poles with the spindle fibers in between
them
2: double stranded chromosomes line up at the equator in the middle of
the cell
, 3: each chromosome Is attached to a separate spindle fiber at the
centromere
ANAPHASE
1: spindle fibers pull apart the pair of identical chromatids
2: centromeres attaching chromatids split In half
3: one chromatid from each side is carried to the oppositee poles
4: single chromatid is one called a chromosome
TELOPHASE
1: daughter chromosomes reach the poles
2: new nuclear membranes surround the chromosomes, forming two nuclei
3: nucleoli reappear
4: chromosomes reappear less condense (unwind) forming chromatin
network identical to the original
5: an invagination starts to form in the middle of the cell
-> end of MITOSIS
CYTOKYNESIS - division of the cytoplasm
1: sharing of the cytoplasm and organelles occurs between two daughter
cells
2: cell membrane grows inwards the middle of the cell until it meets the
center, forming two Identical daughter cells
3: the cell plate grows across the cell and forms a new cell wall between the
two Identical daughter cells
4: the two cells separate and lead their own lives
* cell plate = plant cells
* furrow = animal cells
Where does mitosis take place?
In somatic cells (body cells)
Does not take place in the sex cells (sperm and egg cells)
-> gametes
