1. THE CELL CYCLE

2. THE CELL CYCLE
The events that occur during the cell cycle are a continuous process.
The cell cycle can be broken down into two major steps:
interphase and
mitosis

3. 1. Interphase
Cell grows
Produces new organelles
Copies DNA

4. 2. Mitosis
Mitosis is the division of the nucleus or genetic material of a cell.
Mitosis can be broken down into four phases:
Prophase
Metaphase
Anaphase
Telophase

5. Mitosis is followed by the division of the cytoplasm, cytokinesis.

6. Steps of the Cell Cycle
Animal Cell

7. Interphase period of growth by protein synthesis G1- growth
S - chromosomes replicate (DNA appears as chromatin) centrioles replicate
G2- spindle fibers assembled
not a true phase of mitosis, but prepares a cell for mitosis

8. Prophase able to see double chromosomes
centrioles move to opposite poles
spindle fibers appear and attach to asters from pole to pole
nuclear membrane and nucleolus break down

9. Metaphase
double chromosomes (paired chromatids) attached to spindle fibers by their centromere
move to the middle of equator of the cell

10. Anaphase
chromatids from each double chromosome separate and migrate to opposite poles
centromere leads the way
chromatids cluster together when they reach the poles

11. Telophase chromosomes form chromatin nuclei form around chromosomes
asters and spindle fibers break down
cytoplasm begins to divide

12. Cytokinesis division of the cytoplasm
begins in late anaphase or telophase
a cleavage furrow forms in animal cells at the equator

13. Cytokinesis
a cell plate forms in plant cells and will become the cell wall

14. Differences in plant and animal cell division
plants do not have asters or centrioles

15. Factors that Determine Mitotic Rate
cell type
faster in less specialized cells
ex: skin
age of the cell
fast in young cells
slow in older cells
injured cells
very fast
temperature
affects plants (seasons)

16. Cell Specialization
cell differentiate or become specialized as an organism develops
a specialized cell will have a specific function
ex: nerve sells carry an Impulse
muscle cells contract
leaf cells carry out photosynthesis
red blood cells carry oxygen

17. In multicellular organisms, all somatic cells (body cells) contain a complete generic code, but will only use a part of that code.