51531986 Biology Form 4 Chapter 5 Cell Division
Biology form 4 – Chapter 5
Mitosis
Mitosis is a division of the nucleus to produce two new daughter cells containing chromosomes identical to the parent cell.
Significance of mitosis
Growth- allows a zygote to produce more cell in order to grow
Repair and replacement- allow the multicellular organism maintain its tissues, example skin cells and blood
Asexual reproduction- clone
The cell cycle divided into two major phases
a. Interphase
b. Mitosis
Interphase is the period between division, divided into 3 sub phases (G1, S and G2)
a. G1- cells grow rapidly and new organelle are synthesis
b. S- synthesis of DNA and chromosomes are replicated
c. G2- cells prepares for mitosis, synthesis protein and mitotic spindle begin to form
M PHASE(Cell Division)
Mitosis : nucleus divides
-Prophase -Metaphase -Anaphase -Telophase
Cytokinesis : division of cytoplasm
Prophase
Early prophase
Chomatids condense and become visible in a light microscope
Nucleolus disappears
Paired centrioles move to opposite ends of the cell
Late prophase
Nuclear membrane disappears
Spindle form
Metaphase
Spindle fibres are fully form
Sister cromatids line up at the spindle equator
At the end of metaphase, the centromers divide
Anaphase
Anaphase begin with the separation of the centromers
The sister cromatids are drawn to opposite poles of the cell by contraction of spindle fibres
Telophase
Telophase begin when the two sets of daughter chromosomes have reached the two poles of the cell.
The spindle fibres disintegrate, the nuclear membrane forms around each set of daughter chromosomes and the nucleoli reappear
The chromosomes uncoil and become less visible under the light microscope
-In plant cells, the stages of mitosis are same. Only cytokinesis in plant cells is markedly different.
-A cleavage furrow does not form. Instead, membrane-enclosed vesicle gather at a plant cell’s equator between the two nuclei.
-Vesicle fuse to form a cell plate
Cytokinesis
The division of cytoplasm.
Animal
Mitosis
Mitosis is a division of the nucleus to produce two new daughter cells containing chromosomes identical to the parent cell.
Significance of mitosis
Growth- allows a zygote to produce more cell in order to grow
Repair and replacement- allow the multicellular organism maintain its tissues, example skin cells and blood
Asexual reproduction- clone
The cell cycle divided into two major phases
a. Interphase
b. Mitosis
Interphase is the period between division, divided into 3 sub phases (G1, S and G2)
a. G1- cells grow rapidly and new organelle are synthesis
b. S- synthesis of DNA and chromosomes are replicated
c. G2- cells prepares for mitosis, synthesis protein and mitotic spindle begin to form
M PHASE(Cell Division)
Mitosis : nucleus divides
-Prophase -Metaphase -Anaphase -Telophase
Cytokinesis : division of cytoplasm
Prophase
Early prophase
Chomatids condense and become visible in a light microscope
Nucleolus disappears
Paired centrioles move to opposite ends of the cell
Late prophase
Nuclear membrane disappears
Spindle form
Metaphase
Spindle fibres are fully form
Sister cromatids line up at the spindle equator
At the end of metaphase, the centromers divide
Anaphase
Anaphase begin with the separation of the centromers
The sister cromatids are drawn to opposite poles of the cell by contraction of spindle fibres
Telophase
Telophase begin when the two sets of daughter chromosomes have reached the two poles of the cell.
The spindle fibres disintegrate, the nuclear membrane forms around each set of daughter chromosomes and the nucleoli reappear
The chromosomes uncoil and become less visible under the light microscope
-In plant cells, the stages of mitosis are same. Only cytokinesis in plant cells is markedly different.
-A cleavage furrow does not form. Instead, membrane-enclosed vesicle gather at a plant cell’s equator between the two nuclei.
-Vesicle fuse to form a cell plate
Cytokinesis
The division of cytoplasm.
Animal