1. Mitosis,Cancer & Meiosis

2. Types of Cells
A. Somatic (Body Cells)
- Have 46 Chromosomes
B. Gametes (Sex Cells)
- Egg & Sperm
- Have 23 Chromosomes

3. Cell Growth & Limiting Factors A. Cell size can vary greatly.
i.e. Red Blood cells (8um) & Nerve cells (1m)
B. Cell size is limited.
“Bigger is not Better!”
Diffusion
- Decreases as a cell grows.
- Will take longer for waste to exit a cell or building blocks to enter a cell.
DNA OVERLOAD
Protein production is decreased.

4. III. Chromatin versus Chromosomes
A. Chromatin
- DNA when a cell is not dividing.
- Loosely packed DNA that is
wrapped around proteins (Histones).

5. B. Chromosomes - DNA when a cell is dividing!
- Composed of tightly bound chromatin.
Steps 1-3: DNA forms a chromosome, also called a chromatid.
Step 4: The chromosome has replicated.
Step 5: Duplicated chromosome, before division.

6. IV. Why do cell divide?
A. To replace old, worn out cells.
B. To replace injured / damaged cells.
C. For an organism to grow.
D. For reproduction to occur.

7. V. The Cell Cycle
A. Growth & division of “somatic” cells.
B. A cell has 2 general periods:
1. Interphase – The growth period.
2. Division – The production of “daughter” cells.

8. C. Stages of the Cell Cycle:
1. INTERPHASE (3 sub-phases)
a. G1
- Period of rapid cell growth.
- Lasts roughly 11 hours.
b. S
- Will begin if the “Restriction Point” is passed.
- DNA is synthesized / Chromosomes are copied.
- Lasts roughly 7 hours.
c. G2
- All organelles are copied
- Lasts roughly 3 hours.

10. - DNA coils & becomes chromosomes
2. MITOSIS (P.M.A.T)
STEPS:
1. Prophase
- DNA coils & becomes chromosomes
- The chromosomes have already duplicated themselves and have identical halves called
“Sister Chromatids.”
- The nuclear envelope disappears.
Centrioles separate and form spindle

11. - The chromosomes (Sister Chromatids) line up along the equator.
2. Metaphase
- The chromosomes (Sister Chromatids) line up along the equator.
Spindle Fiber attaches to centromere of sister chromatid
3. Anaphase
- All sister chromatids split.
- One chromatid moves to each side of the cell.
- Remember, each cell only gets 46.

12. - The nucleus reappears. - Chromosomes uncoil into chromatin.
4a. Telophase
- The nucleus reappears.
- Chromosomes uncoil into chromatin.
Spindle Fibers break down
4b. Cytokinesis
- The cytoplasm finally breaks in two.
End Result: Two new identical cells.

15. Chromosome Numbers
A. Diploid
- Refers to cells which carry a double set of chromosomes.
B. Haploid
- Refers to cells with just one set of chromosomes.
C. Homologous Chromosomes
- Refers to two chromosomes which are similar in structure.
- Each contains the same genes.

17. Chromatid & Sister Chromatids 1. Chromatid
- One identical copy of a chromosome.
2. Sister Chromatids
- Two identical chromatids connected together by the centromere.
- Spindle fibers from centrioles will connect to the kinetechore (portion of centromere).

18. Karyotyping
Pictorial display of metaphase chromosomes from a mitotic cell.
Homologous
chromosomes
Used to diagnose genetic
disorders