1. Cell Replication and Genetics

2. Cell Replication

3. What is cell replication? The process of duplicating or making a copy of itself. The process of duplicating or making a copy of itself. Also called cell reproduction or mitosis Also called cell reproduction or mitosis

4. Why do cells go through cell replication? Organism growth Organism growth Repair Repair To copy DNA information to other cells To copy DNA information to other cells Creating offspring Creating offspring

5. Chromosome Structures in the nucleus that contain the hereditary material (DNA) of all cells. Structures in the nucleus that contain the hereditary material (DNA) of all cells. Most “normal” humans have 23 pairs of chromosomes Most “normal” humans have 23 pairs of chromosomes The 23 rd pair determines the gender of the person The 23 rd pair determines the gender of the person How many total chromosomes does each cell contain? How many total chromosomes does each cell contain?

6. Cell Cycle A series of events that takes place from one cell division to the next A series of events that takes place from one cell division to the next Varies from cell to cell (20 minutes in growing animal embryos – 19 hours in some plants) Varies from cell to cell (20 minutes in growing animal embryos – 19 hours in some plants) What else has cycles? What else has cycles?

7. 7 - Cell Division The Cell Cycle 7

8. Mitosis Process in which the nucleus of a cell divides to form two identical cells. Process in which the nucleus of a cell divides to form two identical cells. During Mitosis the cell will go through 5 phases (or steps) During Mitosis the cell will go through 5 phases (or steps)

9. Phase of Mitosis http://www.cellsalive.com/mitosis.htm Interphase Prophase Metaphase Anaphase Telophase & Cytokinesis

10. Interphase occurs before mitosis begins Chromosomes are copied (# doubles) Chromosomes are copied (# doubles) Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy(sister chromosome) change to sister chromatids at end of this phase CELL MEMBRANE Nucleus Cytoplasm

11. Interphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

12. Prophase 1 st step in Mitosis Mitosis begins (cell begins to divide) Mitosis begins (cell begins to divide) Centrioles (or poles) appear and begin to move to opposite end of the cell. Centrioles (or poles) appear and begin to move to opposite end of the cell. Spindle fibers form between the poles. Spindle fibers form between the poles. Centrioles Sister chromatids Spindle fibers

13. Prophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Spindle fibers Centrioles

14. Metaphase 2 nd step in Mitosis Chromatids (or pairs of chromosomes) attach to the spindle fibers. Chromatids (or pairs of chromosomes) attach to the spindle fibers. Centrioles Spindle fibers

15. Metaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

16. Anaphase 3 rd step in Mitosis Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Chromatids (or pairs of chromosomes) separate and begin to move to opposite ends of the cell. Centrioles Spindle fibers

17. Anaphase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

18. Telophase 4th s tep in Mitosis Two new nuclei form. Two new nuclei form. Chromosomes appear as chromatin (threads rather than rods). Chromosomes appear as chromatin (threads rather than rods). Mitosis ends. Mitosis ends. Nuclei Chromatin

19. Telophase Animal Cell Plant Cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

20. Cytokinesis occurs after mitosis Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes. Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

21. Animal Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase

22. Plant Mitosis -- Review Interphase Prophase Metaphase Anaphase Telophase Interphase

23. REMEMBER! Prophase Metaphase Anaphase Telophase Cytokinesis IPMATC I Pray M ore At T he Church

24. Chapter 4 : Section 2 Sexual Reproduction & Meiosis P. 98

25. Types of Reproduction Sexual Sexual –Requires two organisms (or cells) to create an offspring –Ex. Humans, mitosis Asexual Asexual -Requires only one organism (or cell) to create an offspring -Ex. Bacteria, starfish, potatoes, hydra, meiosis

26. Types of Asexual Reproduction Budding Budding –Offspring growing from a parent organism –Ex. hydra Regeneration Regeneration –The ability of an organism to regrow damaged or lost body parts. –Ex. Starfish

27. Sexual Reproduction When two gamete cells join to make another cell When two gamete cells join to make another cell

28. Gametes Males = Sperm Males = Sperm Females = Egg Females = Egg The joining of an egg and a sperm to create a single-celled zygote. Fertilization = The joining of an egg and a sperm to create a single-celled zygote.

29. Haploid vs. Diploid cells Diploid When cells have pairs of chromosomes When cells have pairs of chromosomes Ex. Most typical human body cells Ex. Most typical human body cells (23 pairs = 46 total) (23 pairs = 46 total)Haploid Means “single-form” Means “single-form” When cells have one set of chromosomes When cells have one set of chromosomes Ex. Human gametes (sperm & egg) each have 23 chromosomes Ex. Human gametes (sperm & egg) each have 23 chromosomes

30. Blastula A zygote replicates to become a groups of cells called a blastula. The blastula eventually becomes an organism. A zygote replicates to become a groups of cells called a blastula. The blastula eventually becomes an organism.

31. Why are gametes haploid?

32. Meiosis Haploid cell Replication Haploid cell Replication 1 parent cell creates 4 daughter cells 1 parent cell creates 4 daughter cells Each daughter cell has 23 chromosomes Each daughter cell has 23 chromosomes

33. Why Meiosis? Recombination of chromosomes to pass on to offspring Recombination of chromosomes to pass on to offspring Each gamete cell has to go through the division process twice in order for the cell to end up with half the number of chromosomes. The cells pass on genetic information to the offspring. Each gamete cell has to go through the division process twice in order for the cell to end up with half the number of chromosomes. The cells pass on genetic information to the offspring.

34. Phases of Meiosis Using p. 100, identify each phase of Meiosis Using p. 100, identify each phase of Meiosis

35. Compare and Contrast MitosisMeiosis