1. 1 Cell Reproduction copyright cmassengale

2. 2 Types of Cell Reproduction Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells Asexual reproduction involves a single cell dividing to make 2 new, identical daughter cells Mitosis & binary fission are examples of asexual reproduction Mitosis & binary fission are examples of asexual reproduction Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cells Sexual reproduction involves two cells (egg & sperm) joining to make a new cell (zygote) that is NOT identical to the original cells Meiosis is an example Meiosis is an example copyright cmassengale

3. 3 Cell Division in Prokaryotes copyright cmassengale

4. 4 Cell Division in Prokaryotes Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission Prokaryotes such as bacteria divide into 2 identical cells by the process of binary fission Single chromosome makes a copy of itself Single chromosome makes a copy of itself Cell wall forms between the chromosomes dividing the cell Cell wall forms between the chromosomes dividing the cell Parent cell 2 identical daughter cells Chromosome replicates Cell splits copyright cmassengale

5. 5 Prokaryotic Cell Undergoing Binary Fission copyright cmassengale

6. 6 The Cell Cycle copyright cmassengale

7. 7 Five Phases of the Cell Cycle G 1 - primary growth phase G 1 - primary growth phase S – synthesis; DNA replicated S – synthesis; DNA replicated G 2 - secondary growth phase G 2 - secondary growth phase collectively these 3 stages are called interphase M - mitosis M - mitosis C - cytokinesis C - cytokinesis copyright cmassengale

8. 8 Cell Cycle copyright cmassengale

9. 9 Interphase - G 1 Stage 1 st growth stage after cell division 1 st growth stage after cell division Cells mature by making more cytoplasm & organelles Cells mature by making more cytoplasm & organelles Cell carries on its normal metabolic activities Cell carries on its normal metabolic activities copyright cmassengale

10. 10 Interphase – S Stage Synthesis stage Synthesis stage DNA is copied or replicated DNA is copied or replicated Two identical copies of DNA Original DNA copyright cmassengale

11. On a Chromosome Level: copyright cmassengale11

12. 12 Interphase – G 2 Stage 2 nd Growth Stage 2 nd Growth Stage Occurs after DNA has been copied Occurs after DNA has been copied All cell structures needed for division are made (e.g. centrioles) All cell structures needed for division are made (e.g. centrioles) Both organelles & proteins are synthesized Both organelles & proteins are synthesized copyright cmassengale

13. 13 Mitosis copyright cmassengale

14. 14 Mitosis Division of the nucleus Division of the nucleus Only occurs in eukaryotes Only occurs in eukaryotes Has four stages Has four stages Doesn’t occur in some cells such as brain cells Doesn’t occur in some cells such as brain cells copyright cmassengale

15. 15 Four Mitotic Stages 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase copyright cmassengale

16. 16 Early Prophase Chromatin in nucleus condenses to form visible chromosomes Chromatin in nucleus condenses to form visible chromosomes Mitotic spindle forms from fibers in cytoskeleton or centrioles (animal) Mitotic spindle forms from fibers in cytoskeleton or centrioles (animal) Chromosomes Nucleolus Cytoplasm Nuclear Membrane copyright cmassengale

17. 17 Late Prophase Nuclear membrane & nucleolus are broken down Nuclear membrane & nucleolus are broken down Chromosomes continue condensing & are clearly visible Chromosomes continue condensing & are clearly visible Spindle fibers attach to the centromere of each chromosome Spindle fibers attach to the centromere of each chromosome Spindle finishes forming between the poles of the cell Spindle finishes forming between the poles of the cell copyright cmassengale

18. 18 Late Prophase Nucleus & Nucleolus have disintegrated Chromosomes copyright cmassengale

19. 19 Spindle Fibers The mitotic spindle form from the microtubules in plants and centrioles in animal cells The mitotic spindle form from the microtubules in plants and centrioles in animal cells Polar fibers extend from one pole of the cell to the opposite pole Polar fibers extend from one pole of the cell to the opposite pole Asters are short fibers radiating from centrioles Asters are short fibers radiating from centrioles copyright cmassengale

20. 20 Sketch The Spindle copyright cmassengale

21. 21 Metaphase Chromosomes move to the center of the cell Chromosomes move to the center of the cell Chromosomes are now lined up at the equator Chromosomes are now lined up at the equator Pole of the Cell Equator of Cell copyright cmassengale

22. 22 Metaphase Chromosomes lined at the Equator Asters at the poles Spindle Fibers copyright cmassengale

23. 23 Metaphase Aster Chromosomes at Equator copyright cmassengale

24. 24 Anaphase Occurs rapidly Occurs rapidly Sister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers Sister chromatids are pulled apart to opposite poles of the cell by kinetochore fibers copyright cmassengale

25. 25 Anaphase Sister Chromatids being separated copyright cmassengale

26. 26 Telophase Sister chromatids at opposite poles Sister chromatids at opposite poles Spindle disassembles Spindle disassembles Nuclear envelope forms around each set of sister chromatids Nuclear envelope forms around each set of sister chromatids Nucleolus reappears Nucleolus reappears CYTOKINESIS occurs CYTOKINESIS occurs Chromosomes reappear as chromatin Chromosomes reappear as chromatin copyright cmassengale

27. 27 Cytokinesis Means division of the cytoplasm Means division of the cytoplasm Division of cell into two, identical halves called daughter cells Division of cell into two, identical halves called daughter cells In plant cells, cell plate forms at the equator to divide cell In plant cells, cell plate forms at the equator to divide cell In animal cells, cleavage furrow forms to split cell In animal cells, cleavage furrow forms to split cell copyright cmassengale

28. 28 Cytokinesis Cleavage furrow in animal cell Cell plate in plant cell copyright cmassengale

29. 29 Daughter Cells of Mitosis Have the same number of chromosomes as each other and as the parent cell from which they were formed Have the same number of chromosomes as each other and as the parent cell from which they were formed Identical to each other, but smaller than parent cell Identical to each other, but smaller than parent cell Must grow in size to become mature cells (G 1 of Interphase) Must grow in size to become mature cells (G 1 of Interphase) copyright cmassengale

30. Number of Chromosomes All organisms have a characteristic number of chromosomes. For example, humans have 46 chromosomes. Chromosomes always come in pairs. Why is this? (Hint: How many parents do you have?) copyright cmassengale30

31. Number of Chromosomes Diploid (2n) – a cell containing the full set of chromosomes which make up an organism; having two copies of each chromosome (one from each parent). Example: Body Cells Haploid (n) – a cell with half the number of chromosomes which make up an organism; having only one copy of each chromosome. Example: Sex Cells (Eggs & Sperm Cells) copyright cmassengale31

32. 32 Identical Daughter Cells Chromosome number the same, but cells smaller than parent cell What is the 2n or diploid number? 2 copyright cmassengale

33. 33 Eukaryotic Cell Division Used for growth and repair Used for growth and repair Produce two new cells identical to the original cell Produce two new cells identical to the original cell Cells are diploid (2n) Cells are diploid (2n) Chromosomes during Metaphase of mitosis ProphaseMetaphase Anaphase Telophase Cytokinesis copyright cmassengale

34. 34 Identify the Stages Early, Middle, & Late Prophase Late Prophase MetaphaseAnaphase Late Anaphase Telophase Telophase & Cytokinesis ? ? ?? ? ?? copyright cmassengale

35. 35 Locate the Four Mitotic Stages in Plants Metaphase Prophase Anaphase Telophase copyright cmassengale

36. 36 Uncontrolled Mitosis If mitosis is not controlled, unlimited cell division occurs causing cancerous tumors If mitosis is not controlled, unlimited cell division occurs causing cancerous tumors Oncogenes are special proteins increase the chance that a normal cell develops into a tumor cell Oncogenes are special proteins that increase the chance that a normal cell develops into a tumor cell Cancer cells copyright cmassengale

37. Cancer Carcinogens – substances & agents that are known to cause cancer Examples: Tobacco Radiation Asbestos copyright cmassengale37