Transcript Cell Division

Mitosis
Chapter 10
What Are Chromosomes?
• Strands of DNA
• Every organism has a specific number of
chromosomes
• Before cell division occurs, DNA must be
copied so each new cell will have DNA.
• Once copied, the two
identical strands
(or CHROMATIDS)
are held together by
a CENTROMERE..
Cell Cycle – “Life of a Cell”
• Interphase – growth period of cell, longest stage
of cell life.
1. G1 phase – growth, more organelles
2. S phase – DNA duplication
3. G2 phase – preparation for mitosis
• Cell Division – division of the cell into 2
1. Mitosis – division of the nucleus
2. Cytokinesis – division of the cytoplasm
Section 10-2
The Cell Cycle
G1 phase
M phase
S phase
G2 phase
Mitosis = Cell Division
• Prophase
– cell prepares to be divided; chromatin
condenses, centrioles separate to opposite
sides of cell (animal cells only), spindle forms,
nuclear membrane breaks down
• Metaphase
– Chromosomes line up in middle
• Anaphase
– sister chromatids separate apart
• Telophase
– new nuclear membranes form and begin to tear
the cells in two
Cytokinesis
Division of the cytoplasm
Differences in Cell Division:
1.In animal cells: cleavage of cell membrane
2.In plant cells: a cell plate forms midway
between the divided nuclei
Mitosis Animation
What happens if
something goes wrong
with the cell cycle?
Cancer
• Uncontrolled cell division
• DNA is damaged by carcinogens or
genetically inherited
• Cell will not respond to cell cycle
regulators
• Carcinogens can be radiation or
chemicals
Tumor
Stem Cells
• Cell that have not become
specialized.
• Stem cells can become
any type of human cell.
Abundant in embryos.
• Possible uses in science:
treating nerve damage,
growing organs, treating
diseases.