1. Cell Cycle The process of cell growth that results in cell division to form an identical copy of itself

2. Cell Cycle Cell growth ( Interphase) Cell division (Mitosis) Phases of Cell Cycle

3. Interphase – Cell growth Cell growth and copying of DNA in preparation for cell division. Cell spends about 90% of the cell cycle in this phase Can be divided into sub phases: G 1 phase (“first gap” or 1 st growth phase) S phase (“ DNA synthesis”) G 2 phase (“second gap” or 2 nd growth phase)

4. Cell Cycle Cell growth ( Interphase) G1 PhaseS PhaseG2 Phase Cell division (Mitosis) Phases of Cell Cycle 90% 10%

6. Interphase G1 Phase Cell grows in size Protein synthesis Nucleus intact Whole cell is actively growing S Phase DNA synthesis Replication of DNA 2 copies of each DNA. G2 Phase Cell grows Prepare for cell division Proteins made that are needed for cell division. Centromere appear in animal cells

8. Organization of DNA G1-Phase (Chromatin) DNA+Histone -> coil ->chromatin S-Phase ( daughter DNA strand) Chromatin->(unwind)-> replicate-> 2 daughter DNA strand G2-Phase (forming Chromatids) 2daughter DNA-> condense-> 2 sister chromatids Mitosis ( Chromatids->chromosomes) Sister chromatids->condense-> chromosome Sister chromatids linked at “Centromere”

9. 1 set of DNA(chromatin) 2 sets of daughter DNA Daughter DNA strands condenses to form 2 sister chromatid Interphase G1 Phase Cell grows in size Protein synthesis Nucleus intact Whole cell is actively growing S Phase DNA synthesis Replication of DNA 2 copies of each DNA. G2 Phase Cell grows Prepare for cell division Proteins made that are needed for cell division. Centromere appear in animal cells

10. Overview: The Key Roles of Cell Division The ability of organisms to reproduce best distinguishes living things from non-living matter Growth and development of organism from an egg to an adult require that cells divide and grow. Tissue repair and renewal

11. Chromatin Duplicates itself Coils up into chromosomes Chromatin to chromosomes illustration: Why does DNA need to change from chromatin to chromosome? More efficient division G1 Phase S Phase G2-M Phase

12. o 2 identical “sister” chromatids attached at an area in the middle called a centromere o When cells divide, “sister” chromatids separate and 1 goes to each new cell

13. 1 set of DNA(chromatin) 2 sets of daughter DNA Daughter DNA strands condenses to form 2 sister chromatid Interphase G1 Phase S Phase G2 Phase

14. Cell Division—Mitosis Notes Cell Division — process by which a cell divides into 2 new cells Why do cells need to divide? 1.If cell gets too big, it cannot get enough nutrients into the cell and wastes out of the cell

15. Cell Cycle Cell growth ( Interphase) G1 PhaseS PhaseG2 Phase Cell division (Mitosis) ProphaseMetaphaseAnaphaseTelophase Phases of Cell Cycle 90% 10%

16. Mitosis Nuclear division Involves DNA getting separated into two distinct nucleus

17. The original cell is called the parent cell; 2 new cells are called daughter cells Each daughter cell is exactly like the parent cell – same kind and number of chromosomes as the original cell Parent Cell 2 Daughter Cells

18. Anaphase—(Apart) ProphaseMetaphase—(Middle) Telophase—(Two)Anaphase—(Apart) 4 phases of nuclear division (mitosis), directed by the cell’s DNA (PMAT)

20.  Chromosomes coil up  Nuclear envelope disappears  Spindle fibers form Prophase Spindle Fibers Nuclear Envelope Centriole

21.  Chromosomes line up in middle of cell  Spindle fibers connect to chromosomes Metaphase—(Middle)

22.  Chromosome copies divide  Spindle fibers pull chromosomes to opposite poles Anaphase—(Apart)

23. CC hromosomes uncoil NN uclear envelopes form 22 new nuclei are formed SS pindle fibers disappear Telophase—(Two)

24. Cytokinesis — the division of the rest of the cell (cytoplasm and organelles) after the nucleus divides In animal cells the cytoplasm pinches in In plant cells a cell plate forms After mitosis and cytokinesis, the cell returns to Interphase to continue to grow and perform regular cell activities Cell Plate

25. Cell Cycle Cell growth ( Interphase) G1 PhaseS PhaseG2 Phase Cell division (Mitosis) ProphaseMetaphaseAnaphaseTelophase Cell division (Cytokinesis) Phases of Cell Cycle 90% 10%

26. Cell Cycle

27. Cell Cycle Regulation G0 Stage: - Cell has decided not to divide - Cell does all the normal function G1 Check Point -Between G1 and S phase -Cell decides to divide or delay division G2 Checkpoint -Between S phase and G2 phase -Checks whether the DNA replication was successful M Checkpoint -Between M phase and Cytokinesis -Checks whether nuclear division was successful

28. Mitosis Plant cells

29. Mitosis Animal cells