1. The Cellular Basis of Reproduction and Inheritance
CH. 8
The Cellular Basis of Reproduction and Inheritance

2. Cell Reproduction and Growth Amoeba Sisters
Ch. 8 PART 1
*See the Padlet responses!

3. Where are we in our tour of the cell?

4. WHY DO CELLS REPRODUCE??
to make more cells for replacing old, worn out or damaged cells; repair
for growth and development of an organism
create a new organism
FOR Asexual reproduction only!
BINARY FISSION – Bacteria
BUDDING- Hydra

5. How do cells divide?
Through the Cell Cycle - series of events cells go through to divide and create more cells.

6. DO ALL CELLS GO THROUGH THE CELL CYCLE???
Some cells divide constantly:
embryonic cells
skin cells (every 24 hours)
gut lining cells (2x/day)
Other cells rarely or never divide:
Liver cells (2x/year)
muscle cells
nerve cells (NEVER -> G0)

7. Interphase Most of the cycle was called interphase.
The 3 stages of interphase are called G1, S, and G2.
During interphase, the chromosomes are invisible.
G1 and G2(G=GROWTH!)
cell increases in size
Makes RNA, enzymes, proteins for growth
Commits to divide OR not

8. Interphase S phase (DNA Synthesis) creates a copy of the DNA
from one cell to send a
copy into the new cell
**NOTE: The detailed process of copying of DNA (DNA Replication) will be covered in later chapters!
46 chromosome in a human SOMATIC cell (normal body cell)

9. Regulation of Cell Cycle by ENZYMES
CdK and Cyclin are 2 protein enzymes involved in regulating the cell cycle.
Their role is to ensure each step is completed correctly before moving to the next stage……
so what happens if CdK and Cyclin fail???

10. VOCABULARY TO KNOW! DNA and Chromosomes
DNA contains all the genetic information for creating and running the organism.
Chromosome (condensed chromatin)
Chromatin (DNA wrapped around protein)
Histone (protein)
DNA (genetic material consisting of hereditary info; 1 double helix molecule)
Sister chromatids (1/2 of the DUPLICATED DNA; IDENTICAL!)
Centromere (where sister chromatids attach)

11. 2 SISTER CHROMATIDS = 1 chromosome
AFTER S
BEFORE S

13. M phase = “Mitosis”
Mitosis – division of the chromosomes and organelles that were duplicated in S phase
M phase sends a copy of all the genetic information and necessary organelles into the new cell.
Occurs in most somatic cells (All cells of the body EXCEPT the reproductive cells!)

14. Machinery of Mitosis
Spindle fibers - pull apart chromosomes; extended strands of microtubules made of protein
centromere – where spindle fibers are attached to each chromosome.
Kinetochores – proteins bind to DNA and microtubules at centromere (kinesins= motor proteins)
Centrioles (animal cells)- anchor the other end of the spindle
When the spindle fibers contract, the chromosomes are pulled to the opposing poles or sides of cytoplasm.

15. 4 stages of mitosis Prophase Metaphase Animation Anaphase Telophase
(PMAT)
Animation

16. Prophase First stage of mitosis. 1) The chromosomes condense.
2) The nuclear envelope disappears.
3) The centrioles move to opposite poles.
*During interphase, the pair of centrioles were together just outside the nucleus.
4) The spindle starts to form, growing out of the centrioles towards the chromosomes.

17. Metaphase
1) Short period where the chromosomes are lined up on the equator of the cell (MIDDLE) with the centrioles at opposite ends.
2) The spindle fibers attached to the centromeres.

18. Anaphase The centromeres separate
2) The spindle fibers contract, and the chromosomes are pulled APART (Away) to opposite poles, towards the centrioles.

19. Telophase
1) The cell cytoplasm begins to divide. (cleavage furrow/ cell plates)
2) The chromosomes are at the poles of the spindle.
3) The spindle disintegrates
The nuclear envelope forms around the two separated sets of chromosomes.
(2 separate nuclei, still 1 cell!)

20. Cytokinesis Cell plate:
In plant cells, a new cell wall made of cellulose forms between the 2 new nuclei
Cytokinesis- separation of the cytoplasm into 2 separate cells.
Last stage of cell division (NOT considered part of mitosis)
The organelles get divided up into the 2 daughter cells, whichever cell they find themselves in.
Cleavage furrow:
In animals, a indentation begins from the outside, pinching inwards.

22. Summary of Mitosis Prophase: Chromosomes condense
Nuclear envelope disappears
centrosomes move to opposite sides of the cell
Spindle forms
Metaphase
Chromosomes lined up on equator of spindle
centrosomes at opposite ends of cell
Spindles attach to centromeres on the chromosomes
Anaphase
Centromeres divide: each 2-chromatid chromosome becomes two 1-chromatid chromosomes
Chromosomes pulled to opposite poles by the spindle
Telophase
Chromosomes de-condense
Nuclear envelope reappears
Cytokinesis: the cytoplasm is divided into 2 cells

23. Cancer Cancer is a disease of uncontrolled cell division.
It starts with a single cell that loses its control mechanisms due to a genetic mutation. (usually loss of CDK/cyclin functioning).
Cancer cells enter the S phase WITHOUT waiting for a signal.
Normal cells are mortal. This means that they can divide about 50 times and then they lose the ability to divide, and eventually die. Cancer cells will continue to divide
Tumor - a small mass of cells.
Benign – stops growing and stays at original site.
Malignant – continues to grow in a new site from original.

24. Cancer Progression
Metastasis- cancer cells will break loose and move through the blood supply to other parts of the body, where they start to multiply.
There are many different forms of cancer, affecting different cell types and working in different ways.
All cancers start mutations in specific genes. The mutations are caused by radiation (i.e. UV), certain chemicals (carcinogens- nicotine, pesticides, plastics), and various random events during DNA replication.

25. Cancer Treatments
Typical treatments (traditional Western medicine methods)
Surgery to remove the tumor
Radiation and/or chemicals to kill actively dividing cells.
Radiation & chemotherapy- kill actively dividing cells; but killing ALL dividing cells is lethal.
If any tumor cells are resistant to the chemical treatment, they will survive and multiply (can come back later in a chemo-resistant form)
Using multiple drugs can decrease the risk b/c it’s hard for cells to develop resistance to several drugs at the same time.

26. Cancer Treatments (continued)
Non-traditional methods
Internal chemical re-balance of the body
- strict diets - juicing, raw diets, eliminate sugars as it feeds cells
-supplements- plants with cancer fighting properties (turmeric); vitamin I.V. drips (Vit. C and Vit. D); Blue scorpion venom
Oxygen therapy treatments
Photoimmunutherapy – using infrared light to kill cancer cells targeted by antibodies of your immune system
Stem Cell transplants
Coffee enemas
**Most treatment course require all/multiple methods occurring at the same time!

27. Cancer Treatment (options outside the U.S)
Cancer treatments are constantly being tested and many successful methods are NOT available in the U.S.
(governmental regulations; pharmaceutical and health insurance business
Check out the treatment options at these centers:
Mexico
Germany- #1 German Medical Center and #2 German Intl. Clinic

28. Cell Division Skit Assignment: Show Me MITOSIS and CYTOKINESIS!
NEED: (per group)
4 spindles fibers (short strings)
2 nuclear envelopes (2 long, orange strings)
TIED into a large circle!
4 chromatids (2 chromosomes) = 4 people
2 centrioles = 2 people
Narrator(s) = 1 person or ALL
*No reading from book/notes!
*Must incorporate all phase names/vocab!