1. October 31, 2013 Take out your Cell Division: Mitosis foldable.
Turn in your Reinforcement.
At your table, make two stacks:
One for vocab
One for PowerNotes
Ms. Clark will come around and stamp them later in class.

2. Model of the Cell Cycle
You will work in pairs to model the cell cycle.
Instructions are on your table.
Read the instructions completely before starting the activity.
Leave some space below/around your drawings.

3. Cell Cycle Cell cycle can be broken down into three major parts:
Interphase (maintenance and growth)
Mitosis (nuclear division)
Cytokinesis (cytoplasmic division)
Cells divide at different rates.
Some cells enter a G0 phase.
Cells in G0 carry on normal functions but are unlikely to divide.
Cells will not divide if they live in an environment which:
Lacks essential nutrients, or
Is too crowded/dense.

4. Centrioles
Nuclear
membrane
Chromatin

5. Interphase Cells spend about 90% of their life in interphase.
Purpose of interphase
is to:
Have cells carry out
their normal functions.
Prep cells for division.
Chromosomes in the
nucleus exist in loose
threads of DNA and protein
called chromatin.

6. Interphase
Interphase contains
three stages:
Gap 1
Synthesis
Gap 2

7. Interphase Gap 1 (G1): Cell carries out its normal functions.
Cell grows and replicates its organelles.

8. Interphase
Synthesis (S):
Cell makes a copy of its DNA.

9. Interphase Gap 2 (G2): Cell continues to carry out normal functions.
Additional growth
occurs.

10. Nuclear
membrane
Sister
chromatid
Spindle
fibers
Centrioles

11. Prophase
Chromosomes condense at the start of mitosis, during prophase.
Chromatin condenses into thick rods called chromatid.

12. Prophase Each chromosome in a cell was replicated during interphase.
The two identical chromatids are called sister chromatids.
Sister chromatids are held together at the centromere.

13. Prophase

14. Prophase At the same time, the nuclear envelope begins to break down.
Centrioles, organelles that assist cell division, begin to migrate to opposite sides of the cell.
Spindle fibers grow from the centrioles and radiate to the center of the cell.

15. Prophase

16. Centrioles
Spindle
fibers
Sister
chromatid
Centromere

17. Metaphase
Spindle fibers attach to each pair of sister chromatids at their centromere.
The fibers help move the chromosomes to the middle of the cell.

18. Metaphase

19. Spindle
fibers
Centrioles
Individual, identical
chromosomes

20. Anaphase During anaphase, sister chromatids separate from each other.
Spindle fibers begin to shorten, pulling the identical chromatids toward opposite sides of the cell.
Before Anaphase After Anaphase
Spindle fiber
Chromosome
Centromere

21. Anaphase

22. Cleavage
furrow
Nuclear
membrane
Individual, identical
chromosomes
Centrioles

23. Telophase
Once the complete set of identical chromosomes reach opposite ends of the cell:
A nuclear membrane begins to form around each set of chromosomes.
The chromosomes begin to uncoil out of their tightly-packed form (chromatid) into their loosely-packed form (chromatin).
The spindle fibers fall apart.

24. Telophase

25. Telophase Interphase is the growth and maintenance stage of a cell.
Mitosis is the division of the cell nucleus and its contents.
Stages of mitosis = PMAT
Telophase marks the end of mitosis.
Telophase

26. Identical
daughter cells
Nuclear
membrane
Centrioles
Chromatin

27. Cytokinesis Cytokinesis is the division of the cell’s cytoplasm.
Cytokinesis marks the end of cell division.

28. Cytokinesis Each new cell is called a daughter cell
They are genetically identical to each other.
The daughter cells enter interphase and begin the cell cycle again.

29. Cytokinesis Cytokinesis differs in animal and plant cells.
In animal cells, the cell membrane forms a cleavage furrow.
The daughter cells gradually move apart until their membranes pinch close.
In plant cells, a cell plate
grows between the two
nuclei.

30. Model of the Cell Cycle
Work with your partner to determine the most important points of each phase in the cell cycle.
Write bullet points briefly describing this information.

31. Homework
Section 5.3:
Vocab
PowerNotes
Reinforcement
Section 5.5:

32. Exit Question
What are the four stages of mitosis?