Warm Up

1. Warm Up • In your warm up notebook, list the stages or phases of our lives as humans and then describe in at least one sentence for each stage what we are like. • Example) Fetus- growing and developing in the womb before we are born.

2. Cell Growth and Division

3. Cell division is needed for… • 1. Growth – most organisms grow by producing more cells • 2. Cell Replacement • 3. Reproduction (asexual)

4. Cell division must occur because... • Cells cannot continue to grow indefinitely. • There are two main reasons why they cannot: • 1. A larger cell places more demands on its DNA. • 2. A cell’s volume increases faster than its surface area. • Thus, before the cell becomes too large, it divides.

5. What is Cell Division? Cell division is when a cell divides into two new daughter cells. It occurs in 2 steps: • Step 1: Mitosis – division of the nucleus • Step 2: Cytokinesis – division of the cytoplasm

6. Chromosomes • Chromosomes are thread-like structures of DNA and histones.

7. Chromosomes Continued • A nucleosome is made of a coil of DNA surrounding a histone core and is a subunit that repeats in chromatin.

8. Chromosomes Continued • A chromosome is made up of 2 sister chromatids. • The centromere attaches 2 chromatids. • Chromatin is unraveled DNA

9. Chromosomes Continued • Humans have 23 pairs of chromosomes which equals 46 total chromosomes in each somatic cell. • Somatic cells are diploid (2n) (meaning they contain two complete sets of chromosomes, one from each parent)

10. Turn & Talk • Pick a partner either beside or across from you. • One person has 30 seconds to discuss something new that they have just learned, found interesting, or to mention something they are not sure about. (During the 30 seconds only ONE person should be talking at a time. • After the 30 second timer is up, switch with you partner.

11. The Cell Cycle • Cell Cycle – the series of events that somatic cells go through as they grow, prepare for division, and divides to form 2 identical daughter cells. 2 Phases: 1. Interphase ( G1, S , G2) 2. Mitosis (Cell division) http://images1.clinicaltools.com/images/gene/celldivision/cellcycle.jpg

12. Phases of the Cell Cycle • Interphase – preparation for cell division • Mitosis – the division of the cell nucleus • Mitosis has 4 phases: • Prophase • Metaphase • Anaphase • Telophase • Cytokinesis - division of the cytoplasm • Mitosis results in two genetically identical daughter cells. PMAT

13. Interphase • Interphase – time in-between cell divisions. • Nucleus is still intact and the nucleolus is visible. • DNA is in the form of chromatin (stringy DNA bound to protein) • Includes G1, S, and G2

14. Interphase • Gap 1 (G1)– cells increase in size (growth) and synthesize new organelles( carbs, lipids, proteins). • Synthesis (S) – DNA Replication • Chromosomes are made up of 2 chromatids • Centromere holds chromatids together. • Gap 2 (G2) – Organelles and molecules required for cell division are produced. • Proteins & organelles are made during all 3 phases. • The nuclear envelope is well defined.

15. Turn & Talk • Pick a partner either beside or across from you. • One person has 30 seconds to discuss something new that they have just learned, found interesting, or to mention something they are not sure about. (During the 30 seconds only ONE person should be talking at a time. • After the 30 second timer is up, switch with you partner.

16. Cell Division (M) – division of the nucleus (MITOSIS) & of the cytoplasm (CYTOKINESIS) • Mitosis – the division of the cell nucleus • Mitosis occurs in 4 phases (PMAT): • Prophase • Metaphase • Anaphase • Telophase

17. Prophase • The longest phase of mitosis. • Chromosomes become visible. • Centrioles separate and spindle fibers form. • Centriole- a self-replicating, small, fibrous, cylindrical-shaped organelle, typically located in the cytoplasm near the nucleus. Functions in nuclear division ) • The nucleus (envelope) and nucleolus break down (no longer visible).

18. Metaphase • Chromatids line up on the cell equator. • Centrioles at opposite poles of the cell. • Chromosomes line up at the center (equator) of cell. • Each chromosome is attached to a spindle fiber at the centromere.

19. Anaphase • Cell elongates • The sister chromatids are pulled apart to opposite ends of the cell as spindles pull on the centromere causing it to split.

20. Telophase • Nuclear membrane and nucleolus reform. • Mitotic spindle disappears. • Chromosomes uncoil • Nuclear division is complete.

21. Cytokinesis • Division of the cytoplasm • Pinching in of the cytoplasm, resulting in two genetically identical cells. • In animal, the cleavage furrow of the cytoplasm pinches inward. • In plants, the cell plate forms a new cell wall during telophase.

22. Summary

23. Warm Up In your warm up notebook, describe in two to three sentences the first thing that comes to mind when looking at the stars wars clones.

24. Binary Fission Binary Fission is a form of asexual reproduction which is used by all prokaryotic organisms, and some eukaryotic organisms. like fungi.

25. Binary Fission During binary fission: • The copied prokaryotic DNA is attached to the plasma membrane at two sites. • The plasma membrane then grown in-between the two attachment sites. • Once the cell has almost doubled in size, the plasma membrane pinches inward and a cell wall forms.

26. How is mitosis different from binary fission?

27. Turn & Talk • Pick a partner either beside or across from you. • One person has 30 seconds to discuss something new that they have just learned, found interesting, or to mention something they are not sure about. (During the 30 seconds only ONE person should be talking at a time. • After the 30 second timer is up, switch with you partner.

28. Regulating the Cell Cycle

29. What is Cancer? • Cancer is uncontrolled cell growth. • When cells lose control over growth, a tumor forms.

30. Benign Tumors – are those in which the cancer has not spread into the surrounding tissues or throughout the body. These are not considered cancer because they are localized. • Malignant Tumors- are those in which the cancer does spread into the surrounding tissues. There are also known as cancer. • Metastasis – is when cells break loose from the tumor / from where they started and spread through the body disrupting normal cell activities.

31. Causes of Cancer • There are many causes of cancer: • 1. Chemical – internal or external regulators are not working • 2.Life Style – smoking, radiation exposure, viral infection ( i.e. HPV) • 3. Genetics – defect in p53 and BRCA genes. • p53 protein acts as a tumor suppressor, which means that it regulates cell division by keeping cells from growing and dividing too fast or in an uncontrolled way • BRCA genes function to repair cell damage and keep breast, ovarian, and other cells growing normally

32. Cell Regulators • Cyclin • Protein ( kinase ) found in cells during mitosis that forms the spindles. • These spindles regulate the timing of the cell cycle in eukaryotes

33. Cell Regulators • Internal Regulators- such as the p53 protein and BRCA gene ( as well as cyclin) make sure the cell doesn’t divide (mitosis) until all chromosomes have doubled. • They do this by responding to events inside the cell to make sure the phases of division do not occur to early

34. Cell Regulators • External Regulators- are growth factors (proteins)that stimulate or inhibit growth during the cell cycle. • These prevent organ systems from interfering with each other during embryonic development and healing.

35. In your own words describe what cancer is and how it relates to the cell cycle: