1. Cell Division & Cancer
Day 1

2. Cell DivisionVideo– 5 minutes
play&id=e38296af-06b c0743&pn=resource

3. Objectives
Discuss the results, advantages and disadvantages of asexual and sexual reproduction.
Explain how cell division is controlled.

4. Cell Division Vocabulary
somatic cell – All cells in your body except your gametes; a cell whose genes will not be passed on to future generations.
diploid (2n) – a cell with 2 chromosome sets; all body (somatic) cells
2n=46 for a human
sex or germ cell - a 2n (diploid) cell that is destined to become a gamete (egg or sperm); a cell whose genes can be passed on to future generations.
haploid (n) – a cell with 1 chromosome set; all gametes (sperm, eggs)
n=23 for a human (sperm: male and egg: Female)

6. Cell Division
2 kinds of cell division:
Mitosis: division of the somatic cell’s nucleus (2n creates 2n, asexual reproduction, identical copy)
Meiosis: creation of new sex cells (2n creates n, sexual reproduction, different from each other)
Pancreatic cells
Sperm cells
Human egg cell

7. Cell Cycle
Click Image
A typical cell goes through a process of growth, development, and reproduction called the cell cycle.
Any mutation affecting the cell cycle may cause cell to grow and divide without control (cancer)
To the Teacher: Use image and animation to explain how the cell cycle is closely controlled by checkpoints that guarantee the cell can proceed to the next stage of the cell cycle. Emphasize that any changes in this cycle can lead to uncontrolled growth (cancer)

8. Cell Cycle Interphase M phase G1 S G2 Mitosis Cytokinesis
Prophase Metaphase Anaphase Telophase

9. Cell Cycle: Interphase
The longest phase in the cell cycle is interphase.
The 3 stages of interphase are called
G1 (Gap 1)
S (Synthesis)
G2 (Gap 2)

10. Interphase: G1 -phase G0 Cells spend most of their time in G1
the cell grows and performs its normal function.
Prepares for S phase
Control of cell division occurs in G1: a cell that isn’t destined to divide goes into G0(resting phase, non-dividing phase).
MUSCLE CELL
NEURON

11. Interphase: S-phase
The S phase (“Synthesis”) is the time when the DNA is replicated or copied.
Sister chromatid is now attached at the centromere
Parent strands
Daughter strands

12. Interphase: S-phase DNA duplicates Centromere
Remember chromosome is not condensed, it is still chromatin

13. Interphase: G2-phase G2 is the period between S and mitosis.
DNA replication is checked and the cell is getting ready to divide.

14. G2:
More growth and preparation for mitosis

15. Mitotic (M) Phase: Cell Division
All living cells come from other living cells.
During mitosis, the nucleus of the cell divides, forming two nuclei with identical genetic information. During cytokinesis, the cell divides.

16. Mitosis
Mitosis produces two genetically identical cells called daughter cells which are 2n.
Mitosis is referred to in the following stages:
Prophase
Metaphase
Anaphase
Telophase
Remember PMAT

17. Mitosis: Prophase
In prophase, the cell begins the process of division.
The chromatin condenses. Chromatin coils up to form X shaped chromosomes.
duplicated
chromosome

18. Prophase (continued) Nuclear envelope disappears.
Centrioles migrate to opposite poles of the cell.
Spindle apparatus forms: spindle fibers (microtubules) grow out from centrioles.

19. Prophase: Check for Understanding
Spindle fibers
Aster
Centriole
Sister chromatids
Centromere

20. Mitosis: Metaphase
The chromosomes line up at the equator of the cell (metaphase plate),
the centrioles are at opposite poles
the spindle fibers attached to the centromere.
Centriole
Metaphase plate
Spindle fibers
Apparatus
centromere

21. Metaphase in picture

22. Mitosis: Anaphase
Spindle fibers
In anaphase, the centromere divides because spindle fibers pull the sister chromatids in opposite direction.
At this point, each chromosome goes from having 2 sister chromatids to being 2 separate chromosomes
The spindle fibers contract and the chromosomes are pulled to opposite poles.
Centromere breaks

23. Mitosis: Telophase Chromosomes arrive at opposite poles of the cell.
The nuclear envelope re- forms around the two sets of chromosomes.
Chromosomes uncoil and is now chromatin once again
Division of the Nucleus is complete

24. Cytokinesis in animal cells
Cleavage furrow in a dividing frog cell.
Cytokinesis is the division of the cytoplasm.
Cytokinesis starts during telophase
In animal cells, a Cleavage Furrow forms and separates Daughter Cells

25. Cytokinesis in Plant Cells
In plant cells, a Cell Plate forms and separates Daughter Cells.
Cell Plate forming

26. ANIMAL VS. PLANT MITOSIS
PLANT CELL
No visible centriole or aster
Daughter cells separated by cell plate
ANIMAL CELL
Centriole and aster present
Daughter cells separated by cleavage furrow

28. Proteins Control the Cell Cycle
A mutation in DNA that changes the shape of a protein may make the protein malfunction
The cell cycle is uncontrolled and may allow mitosis to go unchecked and occur very rapidly. This can cause Cancer
When cancerous cell get into the blood stream they can travel all over the body creating more tumors

29. What do living things use Mitosis for?
Maintains Chromosome number in specie’s somatic cells (2n – 2n)
Growth of a living thing
Zygote to embryo to fetus to baby to adult
Repair
Heal wounds
Replace worn out cells
Skin, blood, etc
Asexual Reproduction
All offspring identical to parent (2n)
Limits variation

30. Mitosis Exit Slip
Explain, in detail, what happens to a living cell when it grows.
Explique en detalle lo que sucede a una célula viva cuando crece.

31. MITOSIS RAFT
In a CREATIVE MANNER, explain ALL the steps of the Cell Cycle. You may use poetry, drawings, a diary entry, a short story, comic strip, songs, rap, a news article, a scientific journal entry, etc.