1. PowerPoint chapter review and cancer video
HW 1: p. 101, Write a detailed explanation of the significance of mitosis and be prepared to write about this topic in an essay on Wed’s Quiz HW 2: Study – Quiz on Mitosis Wednesday, do p End of Chapter Questions 1-5 and 9 Midterm Exam Essay due Monday, Dec 18th: The Cells of Henrietta Lacks
Warm up: Label the Phases. On back, use p. 103 to define: stem cell, zygote, totipotent, embryonic stem cells, pluripotent, multipotent, stem cell therapy, and p. 105, mutation, oncogene, carcinogen, malignant tumor, benign tumor, secondary growth and matastisis.
PowerPoint chapter review and cancer video
Worksheet 5.2 – Go over answers from last class
The Cell Cycle Study Guide – Test Review
Measuring Cells With the Microscope Review – Ms. Smith

2. Chapter 5-1: Nuclear division

3. Cell & nuclear division
Cells reproduce by dividing and passing on their genes to daughter cells
Nucleus always divides before cell divides
Each daughter cell contains its own nucleus

4. Cell & nuclear division
Nuclear division combined with cell division allows cells to reproduce themselves for growth or to repair damaged cells
All cells in your body are genetically identical except for gametes – reproductive cells
All cells derived from one cell - zygote

5. Chromosomes
Before division in eukaryotic cells, thread-like structures called chromosomes become visible
# chromosomes depends on species
Ex: Humans = 46, Flies = 8

6. Chromosomes Are single strands before S phase
Double before going into mitosis
Stain very intensely
Prepared photograph of chromosomes called a karyogram

7. Chromosomes Matching pairs are called homologous pairs.
In humans, there are two sets of 23 paired chromosomes. One set from the mother and one from the father

8. Chromosomes Autosomes are numbered 1-22
Sex chromosomes are not numbered and determine the sex of an individual
XY = male, XX=female

9. Chromosomes
Each chromosome has a characteristic set of genes which code for different features

10. Haploid and diploid cells
A cell which contains only one set of chromosomes is described as haploid, as represented by n
Ex“: gametes
Cells that contain 2 sets of chromosomes are described as diploid, as represented by 2n
n= number of chromosomes in one set

11. Chromosomes
Double structure made of two identical structures called chromatids that are joined together
During interphase (period between nuclear divisions) each DNA molecule makes an identical copy of itself (chromatid) and joins them at the centromere

12. Chromatids Each chromatid contains one molecule of DNA
DNA is the molecule of inheritance made up of a series of genes, which is one unit of inheritance.
One genes codes for one polypeptide involved in a specific aspect of the functioning of an organism

13. Chromatids
The gene for a particular characteristic is always found at the same position, or locus (pl. loci)
Total number of different genes in humans is thought to be ~20,000-25,000

14. Homologous chromosomes
Each member of homologous chromosomes comes from one of the parents
23 maternal + 23 paternal = 23 homologous pairs
Each member of a homologous pair possesses genes controlling the same characteristics
A gene for a different characteristic may exist in different forms (alleles) which are expressed differently

15. The cell cycle
Regular sequence of events that takes place between one cell division and the next
Three distinct phases: interphase, nuclear division, cell division

16. Interphase G1 phase: Cell grows to normal size after cell division
S phase: Cell receives signal to start dividing and begins synthesizing DNA
G2 phase: DNA is checked and repaired, cell continues to grow and replicate organelles

17. Mitosis and cytokinesis
M phase (mitosis): growth stops temporarily. Nucleus divides into daughter nuclei
Cytokinesis: Whole cell division. Involved constriction of the cytoplasm between two nuclei

18. Mitosis
Early prophase: chromosomes start to coil up and become visible when stained. Centriole replicate
Late prophase: centrioles move to opposite side of nucleus. Nuclear envelope breaks up into vesicle (not visible) Chromosomes are seen as identical chromatids

19. Mitosis
Metaphase: Centrioles reach opposite ends (poles) and organize spindle microtubules. Chromosomes align at the equator of the spindle. Microtubules/spindle fibers attach to centromeres’ kinetochores

20. Mitosis
Anaphase: chromatids move to opposite poles, pulled by the centromeres
Telophase: chromatids have reached spindle and begin uncoiling. Nuclear envelope reforms.

21. Biological significance of mitosis
Growth: Daughter cells have same number of chromosomes as parent cell and are genetic clones.
This allows growth of multicellular organisms from unicellular zygotes

22. Biological significance of mitosis
Replacement of cells and repair of tissues: Cells are constantly dying and being replaced by new cells. (ex: skin)
Some animals can regenerate entire body parts

23. Biological significance of mitosis
Asexual reproduction: production of new individuals of a species by a single parent organism.
Binary fission – cell division of bacteria
Amoeba, Paramecium – mitosis is how they reproduce
Hydra sponges make a clone of themselves – called budding
Budding can also occur in unicellular organisms or multicellular
Budding is particularly common in plants

24. Biological significance of mitosis
Cloning of B-lymphocytes and T-lymphocytes during immune response is dependent on mitosis

25. The Cell Cycle and Cancer

26. The Stages of the Cell Cycle

27. There are several factors that regulate the cell cycle and assure a cell divides correctly.
1.Before a cell divides, the DNA is checked during G2 to make sure it has replicated correctly.
2. If DNA does not copy itself correctly, a gene mutation occurs.

28. 2. Chemical Signals tell a cell when to start and stop dividing.

29. Neighboring cells communicate with dividing cells to regulate their growth also.

30. Cancer is a disease of the cell cycle
Cancer is a disease of the cell cycle. Some of the body’s cells divide uncontrollably and tumors form.
Tumors in Liver
Tumor in Colon

31. DNA mutations disrupt the cell cycle.
Mutations may be caused by:
1. radiation
2. smoking
3. Pollutants
4. chemicals
5. viruses

32. While normal cells will stop dividing if there is a mutation in the DNA, cancer cells will continue to divide with mutation.

33. Due to DNA mutations, cancer cells ignore the chemical signals that start and stop the cell cycle.

34. Due to DNA mutations, cancer cells cannot communicate with neighboring cells. Cells continue to grow and form tumors.
Skin cancer

35. SUMMARY Normal Cell Division DNA is replicated properly.
2. Chemical signals start and stop the cell cycle.
3. Cells communicate with each other so they don’t become overcrowded.
Cancer Cells
Mutations occur in the DNA when it is replicated.
2. Chemical signals that start and stop the cell cycle are ignored.
3. Cells do not communicate with each other and tumors form.

36. Treating Cancers
Cancer treatments include drugs that can stop cancer cells from dividing.
Watch:
Cancer Documentary

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