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

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

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

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