Chapter 9 Cell Division and Mitosis
Why do Cells divide? (3 things)
Cycle of Life
 The cycle of life includes ___________________ of gametes, _______________________, and
__________________, production of _____________________, and ___________________.
 All of life depends of___________________Overview of Division Mechanism
 Before a cells are able to reproduce, there must be a division of ________________ and its __________
 Mitosis:
o
This division helps cells grow, replace dead, or worn-out cells and repair tissues
 Meiosis:
Chromosomes
 Chromosomes:
 Human DNA is ___________________________ long
 Prior to cell division, each threadlike chromosomes is duplicated to form two sister __________________held
together by a ________________________________
 Centromere:
 Proteins called _____________________ tightly bind to DNA and cause spooling into a structural unit called
_____________________
Mitosis and Chromosome Number
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Each organisms has a definite _________________________
Example: Humans have _______________________________
Chromosomes exists in ____________________ (one from each ______________________)
Humans have ______________________________ of chromosomes
Somatic Cells :
 Germ cells (sperm and egg cells) are:
Cell Cycle
 A recurring sequence of events that extends from the time of a cell’s formation until each division is complete
 Three phases of cell cycle:
Interphase
 Is the portion of the cell cycle is which the cell prepares for cell division (____________- and ______________)
 Three phases of Interphase
 G1 phase:
 S phase:
 G2 phase:
Mitosis Overview
 Nuclear Division that occurs in four phases:
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Spindle apparatus (fibers) moves toward ___________________________
Composed of two sets of _______________________
Extend from two poles of cell and overlap at the cell’s ______________________
Prophase:
 Metaphase (M&Ms):
 Anaphase (Anna’s got to split)
 Telophase:
 Cytokinesis
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Plant Cells
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Animal Cells
Mitosis is Amazing!!!
 Mitosis is accomplished with astonishing _______________________
 There are times when mistakes happen (_____________________________________).
 This is known as a mutation :
Binary Fission
 Prokaryotes cell division (occurs in six steps)
 1 2 3 4 5 6Cell cycle control
 Cell cycle control system: a cyclically operating set of molecules in the cell that both ________________ and
coordinates _____________________ in the cell cycle
 Checkpoint:
 Animal cells generally have built in _______________________ to halt the cell cycle
 3 major checkpoints:
Regulatory Proteins
 1- Kinases:
o
Present at constant concentration throughout the entire cell cycle throughout the entire cell cycle
 2- Cyclin:
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Cyclically fluctuating in the cell cycle
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At _________________times is when you see the fluctuating
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This helps the cell
Growth Factor
 A________________________ released by certain cells that stimulates other cells to grow
Density- dependent Inhibition
 Phenomenon in which crowded cells ____________________________Loss of cells cycle in cancer cells
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Cancer cells :
Transformation the process that converts a normal cell to a _________________
___________________________ recognize a transformed cells and destroys it
However, if the cell evades destruction it may proliferate and form a tumor
(_______________________________________)
Two types of Tumors
 1- Benign:
 2- Malignant:
Metastasis
 Spread of ____________________ to locations distant from their original site
 This is usually done through the _____________________ and __________________________