1 / 30

Cell Growth, Division, and Reproduction

Cell Growth, Division, and Reproduction. Limits to Cell Size. Throughout your lives, how has your body gotten larger? How will this baby penguin grow? How do the cells making up its body compare to those making up the parent’ s body?. A Visual Analogy – what does this town represent.

njimenez
Télécharger la présentation

Cell Growth, Division, and Reproduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Growth, Division, and Reproduction

  2. Limits to Cell Size Throughout your lives, how has your body gotten larger? How will this baby penguin grow? How do the cells making up its body compare to those making up the parent’s body?

  3. A Visual Analogy – what does this town represent Information overload Traffic problems

  4. Cell Growth Limitations Information crisis: too many demands placed on DNA Traffic problems: volume grows too fast relative to surface area, material exchange is insufficient

  5. Smaller cells have a larger (better) surface area to volume ratio

  6. Cell Division Produces two daughter cells Cell must replicate DNA before cell division. Dividing to make more, smaller cells keeps SA to V ratio high.

  7. Comparing Asexual and Sexual Reproduction Asexual Produce many offspring in short period Don’t need to find a mate In stable environments, genetically identical offspring thrive. If conditions change, offspring not well adapted. • Sexual • Relatively fewer offspring; growth takes more time • Need to find a mate • In changing environments, genetic diversity can be beneficial. • Offspring may be less well adapted to current conditions.

  8. The Process of Cell Division

  9. Chromosomes In prokaryotic cells, DNA is packaged into a single, circular chromosome.

  10. Chromosomes In eukaryotic cells, DNA is packaged into multiple chromosomes. DNA double helix duplicated chromosome coils centromere sister chromatids nucleosome supercoils histone proteins

  11. Prokaryotic Cell Cycle Prokaryotes undergo binary fission.

  12. Eukaryotic Cell Cycle Eukaryotic cells have a more complex cell cycle than prokaryotic cells.

  13. Which Cell Cycle? bacteria plants

  14. M Phase Cell division occurs during M phase.

  15. Prophase The nucleus condenses and chromosomes become visible. The spindle begins to form.

  16. Metaphase Chromosomes line up at the center of the cell. centrioles chromatid centromere chromosome

  17. Anaphase Chromosomes move toward opposite poles. individual chromosomes

  18. Telophase The cell begins to divide into daughter cells. nuclear envelopes re-forming

  19. Cytokinesis In animal cells, the cell membrane pinches in the center to form two daughter cells.

  20. Mitosis Overview List and describe the phases of mitosis. Interphase Cytokinesis Prophase 1 Telophase 4 Metaphase 2 3 Anaphase

  21. Cell Differentiation

  22. We start of as one cell. • But after over 47 rounds of the cell cycle you have 47 trillion cells!

  23. Defining Differentiation During the development of an organism, cells differentiate to become . specialized Carry out photosynthesis Transport materials Store sugar

  24. Mapping Differentiation C. elegans 32 256 28 = 25 =

  25. What Are Stem Cells? Stem cells are the cells from which differentiated cells develop. Totipotent: can develop into any type of cell in the body (including the cells that make up the extraembryonic membranes and placenta) – only the fertilized egg and the cells produced by the first division Pluripotent: cells that are capable of developing into most, but not all, of the body’s cell types unspecialized

  26. Embryonic Stem Cells Hollow ball of cells (4 days) • capable of dividing and renewing themselves for long periods; • unspecialized; • give rise to specialized cell types. embryonic stem cells

  27. Adult Stem Cells Multipotent: limited potential to develop into many different types of differentiated cells Mainly found in bone marrow, hair follicles (cells have a limited life span) Also some in brain, heart, and skeletal muscle

  28. Regenerative Medicine Undifferentiated cells are used to repair or replace damaged cells and tissues.

  29. Ethical Issues Human adult stem cell research is rarely controversial because of willing donors. Human embryonic stem cell research is controversial because arguments for and against involve ethical issues of life and death.

  30. Cellular Reprogramming Induced Pluripotent Stem Cells (iPS cells) Convert human fibroblast cells into cells that closely resembled embryonic stem cells May ultimately help society reframe the debate over use of stem cells Dr. Shinya Yamanaka

More Related