1. Ms. Dunlap Cell Growth and Reproduction

2. DO NOW Q1: When a living thing grows, what happens to its cells? Q2: What are the two main reasons why cells divide? A1: Cells increase in number A2: Stay Tuned!!

3. The Big Idea You are constantly changing Worn out cells get replaced Cuts and bruises heal 2-3 billion red blood cells get replaced each second Muscles you exercise get larger

4. The Cell Cycle Cell Division Interphase Growth and Development Preparing for reproduction

5. Cell Growth

6. There are two main reasons why cells divide 1.The larger the cell becomes, the more demands there are on the DNA 2.The cell has trouble moving enough nutrients and wastes across the cell membrane

7. Division of a cell Before it gets too large, a growing cell divides forming two daughter cells The process by which a cell divides into two new daughter cells is called cell division

8. Daughter cells

9. This solves the two problems of a growing cell 1.The cell replicates all of its DNA 2.The actual division of the cell decreases its volume

10. Cell Division

11. In eukaryotes cell division occurs in two main stages 1.Mitosis 2.Cytokinesis

12. Chromosomes In eukaryotic cells, the genetic information that is passed on from one generation to the next is carried on ___________________________ Chromosomes

14. Chromosomes are made of DNA – which carries the cells coded information – and proteins The cells of every organism have a specific number of chromosomes You can’t see chromosomes except during cell division, when they condense and compact

16. Before cell division, each chromosome is replicated, or copied Because of this, each chromosome consists of two identical _______________________________ When the cell divides, the sister chromatids separate and one chromatid goes to each of the two new cells Each pair of chromatids are attached at an area called the centromere “sister chromatids”

17. Interphase “In-between” period of growth between division

18. During the cell cycle, a cell grows, prepares for division, and divides to form two daughter cells, each of which then begins the cycle again The cell cycle consists of 4 phases 1.M phase 2.G 1 phase 3.S phase 4.G 2 phase

20. G1 – Cells do most of their growing. They increase in size and make new proteins and organelles S – Chromosomes are replicated G2 – Organelles and molecules required for cell division are produced M – cell divides

21. DO NOW-SILENTLY 1.Which is a factor that limits cell size a.How active a cell is b.What kind of activity the cell is engaged in c.The ratio of volume to cell surface area d.Whether the plant is an animal or plant cell e.Whether the cell is a prokaryote or eukaryote 2. Using previous knowledge, what are the 2 fundamental differences between meiosis and mitosis. Answer scientifically.

22. Inquiry Question-Knowing when to Stop Suppose you had a paper cut on your finger. Although the cut may have bled and stung a little, after a few days, it will have disappeared, and your finger would be good as new. Think about these questions….

23. …Knowing when to Stop 1.How do you think the body repairs an injury, such as a cut on a finger? 2.How long do you think this repair process continues? 3.What do you think causes the cells to stop the repair process?

24. Prophase The chromatin condenses into chromosomes The centrioles separate A spindle begins to form The nuclear membrane breaks down

25. Metaphase Chromosomes line up down the middle of the cell Each chromosome is connected to a spindle fiber at its centromere

26. Anaphase Centromeres split, allowing sister chromatids to separate The chromosomes move to opposite ends of the cell

27. Telophase Chromosomes unwind A nuclear membrane reforms Nucleolus becomes visable

28. Cytokinesis (In animals…)

29. Cytokinesis (In plants) A cell plate gradually develops into a separating membrane A cell wall then begins to appear in the cell plate

30. Golgi vesicles move toward equator Early cell plate Cell Plate

31. The Big Picture! Mitosis is the division of a ___________ Mitosis produces two nuclei that have the __________ number of chromosomes as the original same nucleus

32. 46 (Before Mitosis) (After Mitosis)

35. 10-3 Regulating the Cell Cycle

36. Controls on Cell Division

37. When cells come into contact with other cells, they respond by not growing When an injury such as a cut occurs, cells at the edges of the injury are stimulated to divide rapidly, the cell division stops when the healing process is complete

38. A sample of cytoplasm is removed from a cell in mitosis. The sample is injected into a second cell in G 2 of interphase. As a result, the second cell enters mitosis.

39. Cyclins Protein that regulates the cell cycle There are 2 types of regulatory proteins; those that occur inside the cell and those that occur outside the cell.

40. Internal Regulators Allow the cell cycle to proceed only when certain processes have happened inside the cell Ex.) several regulatory proteins make sure that a cell does not go through mitosis until all chromosomes have been replicated

41. External Regulators Direct cells to speed up or slow down the cell cycle Ex.) growth factors Molecules found on the surface of neighboring cells often have the opposite effect causing cells to slow down or stop their cell cycles These signals prevent excessive cell growth

42. Cancer A disorder in which some of the body’s own cells lose the ability to control growth When cells divide uncontrollably, masses of cells called tumors can damage the surrounding tissues Cancer cells may break loose from the tumors and spread throughout the body *(DNA interactive DVD)*

43. Q: What causes the loss of growth control? A: smoking tobacco, radiation and chemical exposure, viral infections All cancers have one thing in common: The control over the cell cycle has been broken Some cancer cells will no longer respond to external growth regulators Others fail to produce the internal regulators

44. p53 An astonishing number of cancer cells have a defect in a gene called p53 p53 normally halts the cell cycle until all the chromosomes have been properly replicated if we could fix p53 we could cure many forms of cancer

45. Is a cure in sight? Cancer is a serious disease As difficult as a cure would be, at least scientists know where to start Cancer is a disease of the cell cycle, and conquering cancer will require a much deeper understanding of the processes that control cell division