Section 10-1: Cell Reproduction

1. Section 10-1: Cell Reproduction • Why do cells reproduce? • To help organisms grow and to replace old or damaged cell • Regeneration is the replacement of a lost or amputated body part (ex. Lizard tails, starfish arms)

2. Cell Growth and Division

3. Why do cells divide?) • DNA “Overload” • Not enough information for a big cell • DNA can’t meet the needs of the larger cell • Exchanging Materials • Must be able to eliminate wastes easily • Food, O2 are related to surface area; waste release is related to cell volume • Ratio of Surface Area to Volume – increase surface area to volume ratio. during growth • Volume increases faster than the surface area

4. Cell division reasons continued • All cells are derived from preexisting cells • A process producing new cells • Tissue repair

5. Regulation of Cell Activity All cell activity is regulated by the nucleus • Inside the nucleus, DNA is organized into hereditary units called genes. • A gene is a segment of DNA that controls the production of Proteins. • Genes are loosely arranged in nucleus during Interphase as Chromatin • During Mitosis: coil into chromatids then into chromosomes: DNA Organized/ packaged into structures 

6. Ta Daaa…occurs during The Cell Cycle.

7. Prokaryotic chromosomes vs. eukaryotic chromosomes • A prokaryotic cell has a single, tangled loop of DNA that contains thousands of genes • It never becomes a chromosome • Replicated through Binary Fission producing two daughter cells (one original /one new)

8. Eukaryotic Cells • Eukaryotic cells contain many more genes • arranged on several linear DNA molecules. • Much more complicated • 23 pairs of chromosomes in human cells

9. Every cell except SEX cells have two sister Chromatids Sister Chromatids: replicated chromosomes attached by the centromere Are sister chromotids Chromotidsare identical ? CHROMOSOME STRUCTURE

10. Section 10-2: Mitosis From page 230

11. Cell cycleis a repeating sequence of cellular growth, DNA replication, and division during the life of a cell • Made up of 2Stages: Interphase ,M-Phase • 5Phases: G1,S,G2, Mitosis and Cytokinesis

12. The Cell Cycle in Summary • Interphase – G1 + S + G2 • M phase: Has 2 sub phases • Prophase • Metaphase Mitosis (Has 4 phases) • Anaphase • Telaphase • Cytokinesis

13. So Far: The Cell Cycle • Series of events that cells go through as they grow and divide • 3 Stages - Interphase and M Phase Cytokinesis • 5 phases • G1 phase (cell growth) • S phase (copying DNA) • G2 phase (prepare for mitosis) • mitosis • cytokinesis)

14. The Stages and Phases…Preparing for cell division • Interphase: Cell is growing/ preparing to divide • Includes G1, S, G2 Phases G1: (first gap phase) cell grows rapidly for the cell to build more organelles most of cell’s life spent here! G1checkpoint before moving on to S phase • The cell must be large enough • Cell needs enough nutrition • The cell will enter a resting period if the checkpoint is not passed

15. More interphase… • S: (synthesis phase) cell’s DNA is copied; nucleus contains two complete sets of DNA • G2: (second gap phase) cell continues to grow and prepares to divide; microtubules organize in cytoplasm in preparation to divide G2 checkpoint: Ensures the DNA of the daughter cells will be identical to the parent cell’s DNA, DNA is undamaged, and that the cell is large enough to undergo division

16. Cell division (includes mitosis and cytokinesis) • Process of dividing the nucleus into two is called mitosis . • Process of separating the organelles and cytoplasm is called cytokinesis

17. Structures of Mitosis begin in prophase • Centrioles: Make the spindle fibers and aid on cytokinesis – like logs or straws • Spindle Fibers: separates chromosomes into the daughter cells during cell division to aid in cell seperation

18. Mitosis • Mitosis consists of four phases: • Prophase • Metaphase • Anaphase • telophase refer to page 230 for more detailed descriptions

19. How many cells are there at the end of Mitosis?

20. Prophase • Nuclear membrane breaks down • Centrioles moves to opposite poles and the spindle forms Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming

21. Prophase • Nucleoli disappear • Chromatin condenses (becomes shorter & thicker) • Chromosomes become visible • Centrioles separate & move to opposite poles • Spindle fibers form between the centrioles • Nuclear membrane disappears

22. Metaphase • Chromosomes line up at the equator • Spindle fibers link chromatids at centromeres Section 10-2 Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming Go to Section:

23. Metaphase

24. Anaphase • Spindle fibers shorten and pull sister chromatids to opposites poles of the cell Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming

25. Anaphase

26. Telophase • A new nuclear envelope forms at each pole • The spindle dissolves • Chromosomes uncoil • Cytokinesis begins – nucleus div ides Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming

27. Telophase

28. Cytokinesis • The cell membrane grows into the center of the cell and divides it into two daughter cells of equal size. • Each daughter cell has half of the parent’s cytoplasm and organelles. • Animal Cell Cytokinesis:a belt of protein threads pinch the cell in half • Plant cells cytokinesis: In cells with rigid cell walls, vesicles holding cell wall material line up across the middle of the cell and fuse to form a large membrane-bound cell wall called the cell plate

29. Cytokinesis Spindle forming Centrioles Centromere Chromatin Centriole Nuclear envelope Chromosomes (paired chromatids) Interphase Prophase Spindle Cytokinesis Centriole Metaphase Individual chromosomes Telophase Anaphase Nuclear envelope reforming

30. Cytokinesis

31. Animal vs. Plant Cell Cytokinesis Animal Plant

32. All stages of Mitosis….occur simultaneously

34. Put the phase of Mitosis in order….. • ___ 2. ___ 3. ___ 4. ___ E: Nuclear Envelope disappears – start to see chromatin,centrioles form F: Cell begins to divide, nuclear envelope is formed, chromasomes at opposite ends G: Chromosomes begin to be pulled apart H: Sister Chromatids meet in equatorial zone – form centromere- spindle fibers attach C A B D

35. I hope you got he following….. • D/E 2. B/H 3. C/G 4. A/F E: Nuclear Envelope disappears – start to see chromatin,centrioles form F: Cell begins to divide, nuclear envelope is formed, chromosomes at opposite ends G: Chromosomes begin to be pulled apart H: Sister Chromatids meet in equatorial zone – form centromere- spindle fibers attach C A B D

36. 10.3 Cell Cycle Regulators • Cyclin – a protein which regulates the cell cycle (Hunt and Kirshner) • Internal regulators – proteins that respond to events inside the cell • External regulators – proteins that respond to events outside the cell (e.g. growth factors)

37. Controls on Cell Division External Regulator • Cell-to-cell contact – when cells come in contact with other cells, they stop dividing

38. Regulators and Uncontrolled Cell Growth – Checkpoint Regulators • CANCER • The body’s cell lose the ability to control cell growth • Cancer cells grow out of control, forming tumors (mass of cancer cells) • External and internal regulators don’t work on cancer cells • A disease of the Cell Cycle

39. UNCONTROLLED CELL GROWTH • Cancer Cells do not respond to regulators • Form masses of cell called tumors • Cancer is a disease of the cell cycle

41. Identify CYTOKINESIS of plant and animal cells xxxxxxxxxxxx XXXXXXX xxxxxxx