1. Cell Growth & Division What problems does growth pose for cells?
My sisters keeper
9 -11min (Diagnosis)
23:30-29 (Mom- shaves head feel bad for pain she caused to everyone)
41: :35 (she meets taylor

2. Why do cells need to be small?
DO NOW
Why do cells need to be small?

3. Why do cells need to be small?
Trouble moving enough nutrients and wastes across the cell membrane
Organization
The larger a cell becomes, the more demands on its DNA

4. SA to Volume Ratio plays a role in determining cell size

5. Purpose of cell division?
We start out as one cell!
We need to make more and more cells until we have
about one hundred trillion!

6. Before it divides condenses into chromosomes

8. Chromosomes Chromosome number is unique to every species
Humans: 46 chr.
Chimpanzees: 48 chr.
Yeast: 32 chr.
Adders-Tongue Fern: 1440 chr.!

9. Quality of the Genetic Material and NOT the Quantity
Moral:
Quality of the Genetic Material and NOT the Quantity
give an organism complexity

10. 23 THESE HAVE BEEN DUPLICATED- look closely
Humans have 46 chromosomes- 23 from mom/ 23 from dad
Hey Mom thanks for the 23 chromosomes
REMINDER: each coil DNA that are the instructions for our traits 23

11. Chromosomes Humans have 46 chromosomes in every cell
During S-phase of the cell cycle, all 46 are copied
When the cell splits in half, each new cell has the exact same chromosome # as before

12. MITOSIS Daughter Parent Cell Cells
1:30 seconds Why cant a cell just split into two?
Parent Cell to daughter cells- Note daughter cells look genetically identical to parent cells
DNA replication

14. Checkpoints G1 Checkpoint: G2 Checkpoint M checkpoint Cell size
DNA can be replicated
G2 Checkpoint
DNA intact
DNA duplicated
M checkpoint
- Chromosomes are properly attached to the spindle fibers.

15. What happens if the cell cannot pass through the checkpoint?
Repair the damage OR
2. Self-destruct APOPTOSIS (Programmed Cell Death)
Stop here !!

16. 1. Gap 1 cell grows, doubles organelles
I. Interphase:
90% of the time!
1. Gap cell grows, doubles organelles
2. Synthesis Duplication of the DNA
3. Gap cell grows

17. Steps of Mitosis: (PMAT)
MITOSIS : NUCLEAR DIVISION
During Mitosis the movement of the chromosomes (DNA) are guided by spindle fibers which are long proteins that grow from the centrioles (in animal cells) or the membrane (in plant cells).
Steps of Mitosis: (PMAT)
Prophase
Metaphase
Anaphase
Telophase

18. 1. Prophase- Chromatin fibers condense Nuclear membrane breaks down
Spindle of microtubules forms from centrioles [animals only]

19. 2. Metaphase- “middle”
Spindle fibers from centrioles attach to centromeres
Spindles move Chromosomes to line up in the middle
Centriole
Spindle

20. 3. Anaphase: “away phase”, form “A’s”
Spindle fibers contract
Pull sister chromatids apart
Chromosomes move towards opposite ends
Each side has own copy of DNA
Individual
chromosomes

21. 4. Telophase- “end phase”
Nuclear membranes reform at each pole
Chromosomes unwind
Spindle disappears

22. (NOT a phase of Mitosis)
Cytokinesis
(NOT a phase of Mitosis)
During cytokinesis, the cytoplasm cuts in half
Each daughter cell has an identical set of duplicate chromosomes

23. Cytokinesis in Plants
In plants, a structure known as the cell plate forms midway between the divided nuclei.
No centrioles attach to cell wall

24. Cytokinesis in Animals
Animal cells contract an actin fiber across middle of cell and “pinch” into 2 new cells. - called a “cleavage furrow”.

25. Cancer Cells…
- Do not stop dividing when they contact other cells - Do not respond to signal and divide uncontrollably - Don’t stop at checkpoints and do not do apoptosis - Form masses of cells called tumors - Metastasis: tumor cells break loose and spread in body

26. Contact Inhibition
Normal cells will reproduce until they contact other cells.
When this happens, they stop growing.

27. How are cancer cells different from other cells?

28. Tumors - mass of cancer cells
Tumors - mass of cancer cells. The cells attract new blood vessel growth (this is called angiogenesis)

29. Causes of Cancer/Carcinogens
Random Mutations
Genetics
Chemicals- asbestos, cigarettes,
formaldehyde, pesticides, nitrates
Radiation
Certain viruses (HPV)
Poor Diet/ Obesity

30. Prevention of Cancer Genetic screening BRCA 1 and BRCA 2 Do not smoke
limit alcohol consumption
Maintain a proper diet
exercise
prevent sunburns
Get Proper health screenings

31. Mutations typically happen in two types of genes 1
Mutations typically happen in two types of genes 1. Proto-oncogenes are normal genes that regulate cell growth Oncogenes are mutated proto-oncogenes 2. Tumor suppressor genes – genes that stop the cell cycle or promote apoptosis ex. p53 gene

32. p53 gene, Tumor suppressor gene "guardian of the genome", usually functions to properly control the cell cycle p53 is mutated in over 50% of all human cancers.

33. Biopsy- way to diagnose cancer by surgically
removing piece of tissue and examining it
Staging
- Describes the severity of a person’s cancer - Aids in planning the treatment

34. MEIOSIS
Sperm and egg.

35. Meiosis - the production of haploid cells with unpaired chromosomes - word means "to diminish".
-process creates gametes (sperm and eggs), cells that are haploid (1N)
-gametes combine to create a zygote which is diploid (2N)

36. Meiosis is actually TWO divisions, this results in FOUR daughter cells, each with HALF the number of chromosomes.
These cells are HAPLOID!

37. Homologous Chromosomes
- each chromosome has a match, called a homolog. 
This is why normal organisms always have an even number of chromosomes. 
Chromosomes are numbered and paired according to their size. 
Karyotype showing homologous pairs. 

38. Why Meiosis increases Genetic Variation
During Prophase I - homologous chromosomes pair up and exchange DNA. -
this is called CROSSING-OVER

39. During metaphase, chromosomes line up in PAIRS, but they line up randomly.  This picture shows all the different possible arrangements for an organism with 6 chromosomes.
This is called INDEPENDENT ASSORTMENT

40. Fertilization = combining the genes of two different parents.
When gametes combine, offspring show variation due to independent assortment and crossing over

41. The Phases of Meiosis
Similar in plants and animals.   Plant cells lack centrioles. 

42. Meiosis creates gametes               (sperm and eggs)
Meiosis ensures variability in offspring Gametes combine to create a zygote which is diploid (2N) - process of sexual reproduction

43. Figure 10.9a

44. 3 small polar bodies are formed
During OOGENESIS, cytoplasm divides unevenly during each cytokinesis, resulting in only ONE viable egg cell.
3 small polar bodies are formed
1 large OOCYTE has potential to be fertilized

45. The process results in 4 daughter cells Daughter cells are haploid (N)
Key points of Meiosis
The process results in 4 daughter cells
Daughter cells are haploid (N)
Daughter cells have unique combinations of chromosomes

46. Check for understanding
1.  What phase directly follows metaphase I?
2.  How many cells are present at the end of meiosis I ?
3.  A cell has a diploid number of 60, what is the organism's haploid number? 
4.  Meiosis occurs in what type of cells?
5.  In what phase do homologous chromosomes pair up and crossing-over can occur?
6.  In what phase do the CHROMATIDS separate?
anaphase I 2 30
gametes
prophase 1
anaphase 2

47. Pg 180
Which of these pictures is metaphase I of MEIOSIS and which is metaphase of MITOSIS?
Mitosis                                              Meiosis

48. Mitosis Videos

49. Twilight DOES IT TOO!