Chapter 5, 6.1, & 6.2: Cell Growth and Division

1. Chapter 5, 6.1, & 6.2: Cell Growth and Division

2. 5.1 The Cell Cycle KEY CONCEPT : Cells have distinct phases of growth, reproduction, and normal functions.

3. “All cells come from pre-existing cells” • Two main types of cell reproduction: • Asexual: (MITOSIS) – offspring is identical to the parent cell • Sexual: (MEIOSIS) – offspring is not identical to either parent • produces gametes (sperm and egg cells) Cell Reproduction

4. The complete series of events from one cell division to the next. • Why Do Cells Divide? • Reproduction: new organisms are produced from parents • Growth: multicellular organisms grow by producing more cells • Repair: damaged cells are replaced by producing new cells The Cell Cycle

5. The cell cycle is a regular pattern of growth, DNA replication, and cell division.

6. Interphase: Longest phase of the cell cycle • Gap 1 (G1): cell growth and normal functions • DNA synthesis (S): copies DNA • Gap 2 (G2): additional growth and prepares for division • Mitosis (M): includes division of the cell nucleus (mitosis) and division of the cell cytoplasm (cytokinesis) • Prophase • Metaphase • Anaphase • Telophase The cell cycle has four main stages.

7. CELL CYCLE OVERVIEW

8. What are the stages of cell cycle? G1, S, G2, and Mitosis 2. What happens during G1? Cell grows 3. What happens during S? Replication of DNA 4. What happens during G2? Cell Prepares to divide 5. What happens during M? Cell divides Put it all together!

9. The rate of cell division varies with the need for those types of cells. • Also, cells divide at different rates depending on person’s age. • Some cells are unlikely to divide (G0). Cells divide at different rates.

10. A cell must be big enough to fit all the molecules and organelles it needs to live. • It also must be small enough to quickly transport nutrients and wastes into and out of the cell. • As a cell gets bigger, its volume increases faster than its surface area. Cell size is limited.

11. Surface area must allow for adequate exchange of materials. • Cell growth is coordinated with division. • Cells that must be large have unique shapes.

12. 5.2 Mitosis and Cytokinesis KEY CONCEPT : Cells divide during mitosis and cytokinesis.

13. DNA andhistones SupercoiledDNA DNA doublehelix Chromatin DNA wraps around proteins called histones, forming chromatin. The chromatin coils more and more tightly around organizing proteins. Each continuous ,double-stranded DNA molecule makes one chromosome. Interactions between parts of the histones further compact the DNA Chromosomes condense at the start of mitosis.

14. telomere chromatid centromere telomere Condensed, duplicated chromosome • DNA plus proteins is called chromatin. • One half of a duplicated chromosome is a chromatid. • Sister chromatids are held together at the centromere. • Telomeres (far ends of each chromatid) protect DNA and do not include genes.

15. Telomeres and Aging The Science of Aging http://www.youtube.com/watch?v=x1zw6uRxKYU http://www.youtube.com/watch?v=BkcXbx5rSzw Cancer Risk With Telomere Length http://www.youtube.com/watch?v=PylY3hVzrb4

16. Parent cell centrioles spindle fibers centrosome nucleus with DNA • Longest phase of cell cycle • Interphase has 3 stages: • G1, S, & G2 • The cell contains a pair of centrioles. • The cell's chromosomes have duplicated but are in the form of chromatin. Interphase

17. Mitosis produces 2 genetically identical daughter cells. • Mitosis divides the cell’s nucleus in four phases. • Prophase • Metaphase • Anaphase • Telophase • I remember it as PMAT Mitosis

18. Prophase: • The nuclear membrane begins to disappear • chromosomes condense into chromosomes • spindle fibers form

19. 2) Metaphase: • Spindle fibers attach to centromeres • Spindle fibers line up chromosomes in the middle of the cell.

20. 3) Anaphase: • spindle fibers condense and separate sister chromatids to opposite sides of the cell.

21. 4) Telophase: • chromosomes begin to uncoil • the nuclear membrane reforms • the spindle fibers disappear • Cytokinesis, which divides the cell in two, begins.

22. Cytokinesis • Divides cytoplasm between 2 daughter cells each with genetically identical cells. • Cytokinesis differs in animal and plant cells • In animal cells, cleavage furrow separates two new nuclei • In plant cells, a cell plate forms.

23. Cytokinesis: Animal Cells & Plant Cells

25. Mitosis

26. What stage is this?

27. What stage is this?

28. What stage is this?

29. What stage is this?

30. What stage is this?

31. Mitosis http://www.youtube.com/watch?v=1cVZBV9tD-A

32. Elodea cells

33. Cheek cells

34. Onion Cell Mitosis

35. 5.3 Regulation of the Cell Cycle KEY CONCEPT: Cell cycle regulation is necessary for healthy growth.

36. External factors include physical and chemical signals. • Growth factors are proteins that stimulate cell division. • Most mammal cells form a single layer in a culture dish and stop dividing once they touch other cells. Internal and external factors regulate cell division.

37. Apoptosis is programmed cell death. • a normal feature of healthy organisms • caused by a cell’s production of self-destructive enzymes • a mechanism by which organisms limit the growth and replication of cells. • loss of apoptosis is one of the key mechanisms behind cancer. PICTURE: http://www.brecorder.com/world/north-america/104165-half-of-world-countries-unprepared-to-deal-with-cancer-who.html

38. normal cell cancer cell bloodstream • Cancer cells form disorganized clumps called tumors. • Benign tumors • Remain clustered and can be removed. • Remain at the original site • Malignant tumors • metastasize, or break away, and can form more tumors. • Spread in the body Cell division is uncontrolled in cancer.

39. Cancer cells do not carry out necessary functions. • Cancer cells come from normal cells with damage to genes involved in cell-cycle regulation.

40. Carcinogens are substances known to promote cancer. Carcinogens - College Biology http://www.youtube.com/watch?v=9-I3kKYY7zE

41. Cancer Treatment • Surgery: Remove tumor(s) • Radiation & Chemotherapy: used to disrupt cell division • May have undesirable side effects • Standard cancer treatments typically kill both cancerous and healthy cells

42. FYI: Number of deaths for leading causes of death • Heart disease: 597,689 Risk factors: obesity, smoking, high blood pressure & cholesterol, and diabetes • Cancer: 574,743 Lung cancer causes the most deaths among men & women, followed in women by breast cancer • Chronic lower respiratory diseases: 138,080 smoking & second hand smoking • Stroke: 129,476 Risk factors: alcohol, smoking, obesity, high blood pressure & cholesterol, and diabetes • Occurs when the blood supply to an area of the brain is obstructed, causing brain cells to die • Accidents (unintentional injuries): 120,859 • Alzheimer's disease: 83,494 It’s genetics; memory problems • Diabetes: 69,071 Risk factors: obesity, old age, a family history of diabetes and not exercising • abnormally high blood sugar levels, and can lead to kidney failure, blindness, heart disease • 8. Nephritis and nephrotic syndrome: 50,476 • Nephritis is the inflammation of the kidneys • Nephrotic syndrome is caused by different disorders that damage the kidneys • 9. Influenza and Pneumonia: 50,097 caused by a virus; A seasonal flu shot can help prevent it • 10. Intentional self-harm (suicide): 38,364

43. THE TEN LEADING CAUSES OF DEATH

44. What is cancer? http://www.youtube.com/user/1cancercenter?v=SGaQ0WwZ_0I Cancer Treatments: Radiation & Chemotherapy http://www.youtube.com/watch?v=yrR_s0UzS1M

45. 5.4 Asexual Reproduction KEY CONCEPT: Many organisms reproduce by cell division.

46. parent cell DNA duplicates cell begins to divide daughter cells • Asexual reproduction is the creation of offspring from a single parent. • Binary fission produces two daughter cells genetically identical to the parent cell. • Binary fission occurs inprokaryotes. Binary fission is similar in function to mitosis.

47. 5.5 Multicellular Life KEY CONCEPT: Cells work together to carry out complex functions.

48. SYSTEMS leaf shoot system stem vascular tissue CELL TISSUE ORGAN root system lateral roots primary root • Tissues are groups of cells that perform a similar function. • Organs are groups of tissues that perform a specific or related function. • Organ systems are groups of organs that carry out similar functions. Multicellular organisms depend on interactions among different cell types.

49. organ system organs tissues cells  cells tissue organ organ system organism Lung cell  Lung tissue  Lung  Respiratory System  Person

50. Inner: intestines Outer: skin cells Middle: bone cells • Cells develop into their mature forms through the process of cell differentiation. • Cells differ because different combinations of genes are expressed. • A cell’s location in an embryo helps determine how it will differentiate. Specialized cells perform specific functions.