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How many stages of cell division do you see in this image?

How many stages of cell division do you see in this image?. Cells reproduce by a cycle of growing and dividing called the cell cycle. . This graph is NOT to scale!!. Cell Cycle. Mitosis will be our main focus. First, we will look at Interphase…. ). Interphase.

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How many stages of cell division do you see in this image?

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  1. How many stages of cell division do you see in this image?

  2. Cells reproduce by a cycle of growing and dividing called the cell cycle.

  3. This graph is NOT to scale!! Cell Cycle Mitosis will be our main focus. First, we will look at Interphase… )

  4. Interphase • Longest stage of cell cycle (90%) • Nucleus is visible • Cell is growing during G1 and G2and DNA is being replicated (copied) during S. )

  5. Most of these cells are in Interphase Interphase:3 Phases • G1: Cell is Growing • S: DNA is Synthesized (DNA Replication) • G2: Cell growth; Organelles duplicate in preparation for division )

  6. Limits to Cell Growth Total Surface Area: Height x Width x Number of sides x Number of boxes Total Volume: Height x Width x Length x Number of boxes Surface-to-volume ratio: Surface Area/ Total Volume 6 150 750 1 125 125 6 1.2 6

  7. What’s the problem with a low surface-to-volume ratio? • There are not enough materials entering the cell to meet its demands • Materials have trouble leaving the cell. • The cell can’t make enough mRNA or proteins to meet the demands of the cell. O2 CO2 CO2 O2 CO2 CO2 CO2 CO2 CO2 CO2

  8. What are the key roles of cell division? • Cell division functions in: • Reproduction for some organisms • Growth of an organism from a fertilized egg • Repair of cells that die from normal wear and tear or accidents • Cell division distributes identical sets of chromosomes to daughter cells

  9. Key Vocabulary • DNA molecules are packaged into . • Human (body cells) have 46 • Human (sperm or eggs) have 23 • Chromosomes are made of a material called . chromosomes somatic cells chromosomes. gametes chromosomes. chromatin

  10. Key Vocabulary Chromosome • Chromatin is composed of and . • DNA is supercoiled around proteins called . • Together the DNA and histone proteins form bead-like structures called DNA proteins histones nucleosomes Histones DNA

  11. Key Vocabulary • The chromosome is duplicated during ___ in _____________. • Each duplicated chromosome consists of two . • These are connected by a . S interphase sister chromatids centromere

  12. Mitosis (M Phase) The M Phase consists of: • Mitosis and Cytokinesis Four Stages of Mitosis: Prophase Metaphase Anaphase Telophase

  13. Preparing for Division Late Interphase: G2 Centrosomes (with centriole pairs) 1.Nuclear membrane still visible Nucleolus 2.Chromatin has been replicated

  14. Preparing for Division Late Interphase: G2 Prophase Centromere Early Spindle Apparatus 3.Nuclear membrane disappears 4.Chromosome consisting of two sister chromatids

  15. Metaphase 5. Chromosomes line up at an imaginary line between the centrosomes at opposite ends of the cell. 6.The spindle attaches to the centromeres.

  16. Anaphase 7.Spindles pull the “daughter” chromosomes appart

  17. Telophase Telophase & Cytokinesis 8. Two nuclei become visible In animal cells, a cleavage furrowis visible In plant cells, a cell plate is now visible Cytokinesis 9.The cytoplasm and organelles divide.

  18. RE-identify the stages of Mitosis Interphase:3 Phases • G1: Cell is Growing • S: DNA is Synthesized (DNA Replication) • G2: Organelles duplicate in preparation for division )

  19. What’s the end product? • Two identical daughter cells ready to start the cycle again… or not. • Some cells (like your nerve and muscle cells) do not undergo division. • For those that do (your skin and the lining of your intestinal tract) how would you know how quickly division takes place?

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