Cell Division & Reproduction

1. Cell Division & Reproduction By: Maryn S.

2. Introduction • Cell division and reproduction • Mitosis • when the nucleus of a eukaryotic cell divides. • Replacing worn out cells and producing offspring identical to parent • Meiosis • The division of a cell and its nucleus that produces haploid daughter cells • Ensures fertilization with proper chromosome numbers

4. Interphase • G1 • cell carries out normal functions • does not reproduce • S • chromosomes inside the cell replicate (sister chormatids) • Sister chormatids are held together near the middle of the centromere • ensures replication of cells by cell division are identical • G2 • cell continues to grow • organelles replicate

5. Mitosis (start of the Mitotic stage) • when the nucleus of a eukaryotic cell divides. • Importance of Mitosis • replacing old, wore out, or dead cells • reproducing offspring identical to the parent (asexual reproduction)

6. Phases of Mitosis • Prophase • Metaphase • Anaphase • Telophase

7. Prophase • The first step in Mitosis • Major events • the replicated chromosomes of DNA coil tightly together • the membrane around the nucleus breaks apart allowing the chromosomes to move to freely around the cell

8. Metaphase • The second phase of Mitosis • Major events • Hair-like fibers move replicated chromosomes to the middle of the cell • replicated sister chromatids align at the middle of the cell

9. Anaphase • The Third phase of Mitosis • Major events • Hairlike fibers attach to the sister chromatids of every replicated chromosomes • Fibers pull and separate replicated chromatids to opposite ends of the cell • chromatids begin being called chromosomes

10. Telophase • The fourth phase of Mitosis • Major events • A new membrane forms around each set of chromosomes • Coiled chromosomes begin to unwind • There are two new chromosomes that are identical to the original one • The cell has not yet divided

11. Cytokinesis • The final phase of cell division • Major events • The cytoplasm and its components divide into two identical daughter cells

12. (jello) Cell Pictures of Mitosis

14. Meiosis • The division of a cell and its nucleus that produces haploid daughter cells • Importances • It ensures the common chromosme inheritance numbers • Ensures fertilization with proper number of chromosomes

15. Sexual Reproduction (Meiosis) • The production of an offspring that results when the genetic materials from two different cells combine. • Advantages • Genetic variation • Selective breeding • Disadvantages • Difficulties of sperm and egg fertilization • Time spent to grow and develop to be able to reproduce

16. Asexual Reproduction(Mitosis) • The production of offspring by one parent without a sperm and an egg joining • Advantages • Does not require a mate • Less time input for more reproduction • Identical offspring is well developed for the same environment (cloning) • Disadvantages • Lack of genetic variation • Genetic mutations that pass through generations

17. Conclusion • Cell division and reproduction • Mitosis • when the nucleus of a eukaryotic cell divides. • Replacing worn out cells and producing offspring identical to parent • Meiosis • The division of a cell and its nucleus that produces haploid daughter cells • Ensures fertilization with proper chromosome numbers • In both ways of reproduction there is still the foundation of the process cell division.

18. Thank You!!!

19. Bibliography • http://botit.botany.wisc.edu/images/130/Meiosis/Lilium_microsporogenesis/Meiosis_1.low.jpg • http://wwwdelivery.superstock.com/WI/223/1436/PreviewComp/SuperStock_1436R-196024.jpg • http://dogtime.com/system/gallery_pictures/26/large/Golden-Retriever-puppy-3-picture.jpg • http://research.nmsu.edu/molbio/bioinfo/tutorials/clip_art/images/mitosis.jpg • http://upload.wikimedia.org/wikipedia/commons/7/7b/MajorEventsInMeiosis.jpg • National Geographic, Focus on Life Science; McGraw Hill, 2007