1. Today you will:
explain why cells divide
describe the steps of mitosis
define terms used to describe the events of mitosis

2. Why Cells Divide
cells divide once they reach a certain size
produce two cells, therefore it decreases their surface area to 
volume ratio
cell membrane provides surgace area for exchange of nutrients 
and wastes
volume increases when a cell is growing, much more rapidly than 
the surface area
if a cell gets too large, surface area is too small for adequate 
exchange of materials the cell will die du to the buil-up of wastes 
and iadequate food and oxygen supply therefore the cell must 
divide
DNA must have been replicated whenever cell division occurs so 
each cell receives complete instructions once the division is 
compete
numbers vary with the species
the number of chromosomes can be considered as a number of 
pairs
regardless of how many chromsomes an organism has, each one 
has a matching chromosome
a matching pair are called "homologous" chromosomes

3. Cell Cycle Steps of Mitosis Definitions Define the following terms.
interphase - portion of cell cycle when the cell isn't dividing
cells is actively making materials (nucleic acids, proteins) needed for 
growth and repair
Characteristics
nucleus is surrounded by the nuclear membrane with a nucleolus 
present
chromosomes are in chromatic form
centrioles present outside the nuclear membrane in animal cells only 
(centrioles help move chromosomes during cell division)
DNA is duplicated during interphase
B30 U3 L1 Cell Cycle HO.doc
Steps of Mitosis
B30 U3 L1 mitosis notes.pdf
Definitions
Define the following terms.
1. Centrioles
2. Spindle Fibres
3. Asters
4. Chromatids
5. Chromosomes
6. Chromatin
7. Centromere
8. Cytokinesis

7. Attachments
B30 U3 L1 Cell Cycle HO.doc
B30 U3 L1 mitosis notes.pdf