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How do you grow? Give examples and be specific.

How do you grow? Give examples and be specific. . Welcome Back!!!!!!!!!!!. Word of the Day: tangent (‘tan jent ) adjective - touching at only one point In the middle of her discussion of her dog’s symptoms with her vet, she went off on a tangent about her pet’s cute behavior.

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How do you grow? Give examples and be specific.

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  1. How do you grow? Give examples and be specific. Welcome Back!!!!!!!!!!! • Word of the Day: tangent (‘tan jent) adjective - touching at only one point • In the middle of her discussion of her dog’s symptoms with her vet, she went off on a tangent about her pet’s cute behavior.

  2. Cell Division (Mitosis)

  3. Mitosis Basic Cell Reproduction

  4. What if there was no more Mitosis?

  5. Reasons for Mitosis: • Generate new cells for: • Growth • Repair • Maintenance

  6. DNA • Deoxyribonucleic acid • During mitosis, DNA gets reorganized from messy, spaghetti-like CHROMATIN into organized, neat CHROMOSOMES! • Humans have 46 chromosomes (23 from your mom, 23 from your dad)

  7. Chromosome number Just the way the DNA is packaged! How many do certain organisms have?? Amoeba= 50 Cat = 32 Goldfish =94 Earthworm= 36 Human = 46

  8. Neat & tidy chromosome Relaxed chromatin

  9. Chromosome structure • After DNA replication the chromosomes become visible by condensing. This is the beginning of mitosis Chromosomes= 2 sister chromatids and a centromere holding them together (see next page!)

  10. Chromosome

  11. Neat & tidy chromosome Relaxed chromatin

  12. What initiates cell division? • A cell or cells that need to undergo cell division receive a signal to begin division QUESTION: What do you think are examples of division signals?

  13. Signal Received. What happens next? • The cell must prepare for division. • Assuming you are a cell that has just received a division signal, turn to your neighbor and explain what you think you would need to do in order to make an exact replica of yourself. Your Turn!

  14. Preparation - Interphase. • Interphase is the preparation stage for a cell going through division • During interphase, 3 main preparations occur: • Growth • DNA replication (4692 Chromosomes)*IN HUMANS • New organelles and cellular materials are made (proteins made in ribosomes!

  15. Interphase G1 G1: Growth 1 S: Synthesis G2: Growth 2 S

  16. Cell Cycle= interphase and mitosis • Interphase= the “getting ready” period between cell divisions. Contains G1, S, and G2 • G1= Gap one phase. Cell grows to be able to divide. • S Phase= DNA synthesis • G2= Gap two phase. More growth! Specifically, the growth of new cell organelles and materials required for cell division

  17. Why is interphase so important? • A cell must prepare accurately in order to divide into two identical cells • DNA must be replicated properly so that both cells have the same genetic material (46  92  46) *IN HUMANS • The cell must grow and make new organelles/cellular material in order to give half to the new cell

  18. Preparation complete! • The cell is now ready to undergo mitosis!

  19. Steps of Mitosis Prophase -Microtubules start to form -Nuclear envelope starts to disappear 2. Metaphase -Chromosomes align at the center of the cell (metaphase plate) -Spindles attach to the chromosomes (each chromatid)

  20. Steps of Mitosis 3. Anaphase -Spindle fibers shorten to pull sister chromatids apart 4. Telophase -Nuclear envelope starts to reform -Cell elongates

  21. Lets look at that again…

  22. Early Prophase

  23. Late Prophase

  24. Early Metaphase

  25. Late Metaphase

  26. Anaphase

  27. Telophase

  28. What happens during mitosis?Chromosome alignment. • The replicated chromosomes (DNA) move towards the middle • This alignment allows the chromosomes to be separated equally between the two cells • Proteins move and align the chromosomes

  29. What is the point of alignment? B. A. What would be the result of these two cells dividing?

  30. Mitosis • http://labs.bio.unc.edu/Salmon/

  31. What happens during mitosis?Physical division (Cytokinesis). • Not only is the DNA divided equally, but the new organelles and cellular material must be divided equally as well • The cell pinches or furrows in the middle then physically separates into two identical cells. (cleavage) • This phase is called cytokinesis.

  32. What is the result of mitosis? • Two identical cells (the original and a new cell) • Think of a photocopier machine: (Interphase, mitosis, cytokinesis) Original (46 chromosomes) Copy (46 chromosomes)

  33. Plant Cell Division • Plant cells divide just like animal cells EXCEPT they do not have centrioles and their cell wall causes cytokinesis to occur differently A new cell wall forms in between the two new cells in plant cells rather than furrowing/cleavage

  34. Mitosis in action! Cross section of a wound SCAB BLOOD (BLOOD CELLS) UNWOUNDED SKIN CELLS UNDERLYING BLOOD VESSEL

  35. Zooming in on one cell in the cross section… Alert! -Growth -DNA Replication -More Organelles Made Cell receiving division signal Cell undergoing mitosis

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