Section 10-2: Cell Division
· Cells divide for:
o Growth of organism & keeping cell size ______:
1) exchange of materials (oxygen, food, wastes)
2) allows DNA to control needs of cell
o ______: replace old cells or repair damaged cells.
v Chromosomes: made of DNA and carry the genetic information
· Human cells have ______
· Duplicate before cell division which makes sure each new cell has a copy of genetic information:
1) Duplicated pairs of chromosomes are called
______.
2) Chromatids are held together by a ______.
ü ______: cycle of growth and division by a cell (4 phases)
§ Interphase:
G1 – growth
S - DNA copies itself
G2 – cell prepares for cell division
§ Cell begins division in M phase = ______
· ______: nuclear division of a cell that results in 2 cells with the same genetic information.
Ø Four phases: PMAT
Ø ______:
1) first phase where chromosomes can be seen
2) centrioles move to opposite sides
3) spindle forms & fibers attach to chromosomes
4) nucleolus & nucleus disappear
Ø ______
1) chromosomes line up in the center
Ø ______
1) chromosomes separate at centromere
2) individual chromosomes move to opposite sides of the cell
Ø ______
1) final phase of mitosis
2) nucleus begins to form around each set of chromosomes
3) spindle disappears
4) nucleolus reappears
· ______: division of the cytoplasm
Ø Animals – cell pinches in and 2 cells have formed
Ø Plants – a ______forms separating the 2 new nuclei, then cell wall forms.
Section 10-3: Regulating the Cell Cycle
· ______are special proteins that regulate the cell cycle in eukaryotes. Examples: internal regulators, external regulators
· ______: uncontrolled cell division that forms masses of cells or tumors.
Ø Causes:
1) ______: greater risk of developing cancer if family member has it.
2) ______: ultraviolet radiation (excess sun exposure), air pollution, virus infection
3) ______choices: tobacco use, diet, lack of exercise
4) Defect in ______which normally stops cell cycle if duplication process of chromosomes is not finished.
* ______leading cause of death in U. S.
Section 10-2: Cell Division
· Cells divide for:
o Growth of organism & keeping cell size small:
1) exchange of materials (oxygen, food, wastes)
2) allows DNA to control needs of cell
o Maintenance: replace old cells or repair damaged cells.
v Chromosomes: made of DNA and carry the genetic information
· Human cells have 46 chromosomes
· Duplicate before cell division which makes sure each new cell has a copy of genetic information:
1) Duplicated pairs of chromosomes are called chromatids.
2) Chromatids are held together by a centromere.
ü Cell Cycle: cycle of growth and division by a cell (4 phases)
§ Interphase:
G1 – growth
S - DNA copies itself
G2 – cell prepares for cell division
§ Cell begins division in M phase = Mitosis
· Mitosis: nuclear division of a cell that results in 2 cells with the same genetic information.
Ø Four phases: PMAT
Ø Prophase:
1) first phase where chromosomes can be seen
2) centrioles move to opposite sides
3) spindle forms & fibers attach to chromosomes
4) nucleolus & nucleus disappear
Ø Metaphase
1) chromosomes line up in the center
Ø Anaphase
1) chromosomes separate at centromere
2) individual chromosomes move to opposite sides of the cell
Ø Telophase
1) final phase of mitosis
2) nucleus begins to form around each set of chromosomes
3) spindle disappears
4) nucleolus reappears
· Cytokinesis: division of the cytoplasm
Ø Animals – cell pinches in and 2 cells have formed
Ø Plants – a cell plate forms separating the 2 new nuclei, then cell wall forms
Section 10-3: Regulating the Cell Cycle
· Cyclins are special proteins that regulate the cell cycle in eukaryotes. Examples: internal regulators, external regulators
· Cancer: uncontrolled cell division that forms masses of cells or tumors.
Ø Causes:
1) genetic or hereditary: greater risk of developing cancer if family member has it
2) environmental: ultraviolet radiation (excess sun exposure), air pollution, virus infection
3) lifestyle choices: tobacco use, diet, lack of exercise
4) defect in gene p53 which normally stops cell cycle if duplication process of chromosomes is not finished.
o Second leading cause of death in U. S.