1 / 21

II. CELL DIVISION

II. CELL DIVISION. centrioles. spindle fibers. Chromatin. DNA double helix. DNA and histones. Supercoiled DNA. centrosome. nucleus with DNA. During Interphase , cells prepare for division Grow Replicate DNA Cell functions Mitosis = Cell Division portion of cell cycle

afric
Download Presentation

II. CELL DIVISION

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. II. CELL DIVISION

  2. centrioles spindle fibers Chromatin DNA doublehelix DNA andhistones SupercoiledDNA centrosome nucleus with DNA • During Interphase, cells prepare for division • Grow • Replicate DNA • Cell functions • Mitosis = Cell Division portion of cell cycle • Must prepare DNA first • DNA wraps around proteins to condense it • Forms chromosomes • 2 copies of 9ft of DNA to pack up and separate! Chromosome

  3. Animation

  4. c) Chromosome structure: chromatid Original DNA Copied DNA centromere DUPLICATED CHROMOSOME (+ copied DNA) CHROMOSOME (condensed DNA) SISTER CHROMATIDS

  5. d) Humans have 2 sets of 23 chromsosomes

  6. Human Karyotype One from Dad One from Dad One from Dad One from Dad One from Dad One from Mom One from Mom One from Mom One from Mom One from Mom MALE OR FEMALE? #1-22 = Autosomal Chromosomes #23 = Sex Chromosomes

  7. MALE OR FEMALE?

  8. What’s different about this karyotype? MALE OR FEMALE? One from Dad One from Mom Duplicated Chromosomes

  9. DUPLICATED OR UNDUPLICATED CHROMOSOMES? MALE OR FEMALE? WHAT’S DIFFERENT ABOUT THIS KARYOTYPE?

  10. DUPLICATED OR UNDUPLICATED CHROMOSOMES? MALE OR FEMALE? WHAT’S DIFFERENT ABOUT THIS KARYOTYPE?

  11. B. Mitosis (contin) • Occurs in all body cells • not reproductive cells • One cell divides into TWO identical cells • Each having 2 sets of 23 chromosomes One set from… Mom One from Dad

  12. 4. Mitosis occurs in Phases: • Prophase • Metaphase • Anaphase • Telophase To remember the order, Think of an acronym….

  13. centrioles spindle fibers nucleus with DNA centrosome Review…. • Prior to Mitosis, what part of the CELL CYCLE is the cell in? • What is happening during this stage? Prior to Mitosis: Interphase

  14. a) Prophase • Chromosomes become visible • (DNA condenses) • Nuclear membrane breaks down and disappears • Centrioles separate and move to opposite ends of the cell • Spindle fibersdevelop from the centrioles • Chromosomes begin to attach to spindle fibers • Longest stage of mitosis

  15. b) Metaphase • Chromosomes complete attachment to the spindle fibers at the centromere • Chromosomes line up at the center of the cell

  16. c) Anaphase • Cell elongates • Sister chromatids split at the centromere • Chromatids are pulled to opposite ends of the cell by spindle fibers • Shortest phase of mitosis • One set of single stranded chromosomes at each end of the cell

  17. d) Telophase • Final stage in Mitosis • Cell membrane begins to pinch in the middle • Nuclear membranes begin to form around each group of chromosomes at each end of the cell • Chromosomes no longer visible (DNA = Chromatin) • Spindle fibers break apart

  18. C. Cytokinesis • Separates cytoplasm and organelles • Cell divides • Results in two identical daughter cells • Differs in plants and animals: • Animals: membrane pinches in • Plants: must form cell plate first

  19. InterphaseProphase Metaphase Anaphase Telophase Animation 1 Animation 2 Microscopic Time-lapsed Video

More Related