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Week #2 Quarter 2 (10 /21) PowerPoint Presentation
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Week #2 Quarter 2 (10 /21)

Week #2 Quarter 2 (10 /21)

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Week #2 Quarter 2 (10 /21)

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  1. Today in Biology Homework: Make sure- review turned in vocabulary complete Week #2 Quarter 2 (10/21) Biology Learning Goal: Overview of chapter 6 – Genes, DNA, Chromosomes and chromatids Warm Up Question: Look at definition of binary fission. Does this happen in prokaryotes or Eukaryotes? Explain. Fact of the Day Rats multiply so quickly that in 18 months, two rats could have over 1 million descendants. • To Do Today: • Make sure review from Q.1 is turned in. • Complete vocabulary words for Chap6 • Make sure notebook Q2 notebook done

  2. Today in Biology Homework: None Week #2 Quarter 2 (10/22) Biology Learning Goal: Overview of chapter 6 – Genes, DNA, Chromosomes and chromatids Warm Up Question: What do you know about Mitosis? Explain. Fact of the Day If one was to weigh all of the land animals of the earth, 10% of that mass would be ants. • To Do Today: • Check notebook – complete • Overview of Chapter 6 Notes

  3. Review of Cells Over view of cells • • introduction to cells segment. human anatomy - the body made entirely of cells - which make up tissues - which make up organs - which make up organ systems - which make up you 4 1

  4. How do terms differ in meaning Cell division and gamete Cell division process in which new cells form Gametes=reproductive cells that form by one type of cell division Gene and DNA DNA is a substance made of nucleotides that stores information about when and how to make proteins Genea segment of DNA that codes for a protein or RNA molecule

  5. 5 6

  6. draw Chromosome and chromatids Chromosomes=structures made of DNA and associated proteins Chromatids=two parts of a chromosome that contain identical copies of DNA and are joined by centromere. TELOMERE TELOMERE


  8. How do little elephants grow up to be BIG elephants?

  9. Why do animals shed their skin?

  10. Three reasons why cells reproduce by asexual reproduction (divide):1. Growth2. Repair3. Replacement Skin cancer - the abnormal growth of skin cells - most often develops on skin exposed to the sun. Cell that reproduce by asexual reproduction reproduce constantly.

  11. What is Mitosis?

  12. Mitosis • MITOSIS- reproduction of somatic (body) cells also known as NUCLEAR DIVISION

  13. TERMS USED……….. • Diploid= full # of chromosomes or (2n) • Haploid= half # of chromosomes or (n) • SOMATIC CELLS is any biological cell forming the body of an organism; that is, in a multicellular organism, any cell other than a gamete, germ cell, gametocyte or undifferentiated stem cell. (ex. skin, nerve, muscle cells)

  14. Today in Biology Homework: None Week #2 Quarter 2 (10/23&24) Biology Learning Goal: Overview of chapter 6 – Genes, DNA, Chromosomes and chromatids Warm Up Question: Explain the difference between haploid and diploid cells. Fact of the Day A hedgehog's heart beats 300 times a minute on average • To Do Today: • Check notebook – complete • Begin discussion on cell cycle • Mitosis notes • Mitosis flip book

  15. Cell cycle Cell cycle and reproduction

  16. Cell Cycle Page 7 • Regular sequence of cell growth and division • Time it takes varies with type of cell and external factors

  17. Phases of cycle G1 S G2 Mitosis Cytokinesis • Cell increases in size • New organelles made • DNA replication (copying) • Preparation of structures needed for mitosis & cytokinesis • Chromosomes begin to coil and condense (shorten & thicken) • Division of material in nucleus • Division of cytoplasm and organelles animation__mitosis_and_cytokinesis.html

  18. Prophase Spindle fibers centrioles • Chromatin shortens and thickens • Nuclear membrane and nucleolus disappear • Spindle fibers appear and attach • In animals, centrioles move to poles nucleus chromatid centromere Chromosome with replicated DNA

  19. Metaphase • Chromosomes line up single file at equator Equator Pole Pole Spindle fibers

  20. Anaphase • Chromatids separate • Chromatids move to opposite poles • Each chromatid is now called a chromosome Pole Pole

  21. Telophase • Begins when chromosomes reach poles • Spindle disappears • Nucleus is re-formed • Chromosomes diffuse to become chromatin • Cytokinesis may occur

  22. Cytokinesis • Division of cytoplasm • Usually occurs during telophase • In animal cells – cleavage furrow that constricts cytoplasm • In plant cells – cell plate forms between two cells

  23. When mitosis ends – two new cells with same amount of DNA

  24. Reasons for Mitosis • Formation of adult from fertilized egg (development) • Maintenance or repair • Growth in multicellular organisms • Asexual reproduction in one-celled organisms Mitosis – Mr. Parr

  25. Review In the 17th century, Robert Hooke peered through a microscope at a slice of cork and discovered that it was composed of cells. Centuries later, Rudolf Virchow set forth the cell theory, in which he proposed that the cell was the basic unit of all living organisms. We now know that this theory is true; cells make up all living things, whether they are plants, animals, or microorganisms. There is only one way to make more cells—by the division of those that already exis 16 14

  26. Goal of the Cell Cycle: To produce two genetically identical cells from one precursor cell. • Copy and pass on its genetic information to the next generation of cells. This requires the replication of the DNA in each chromosome 2. Accurate separation of the chromosomes into the daughter cells so that each cell receives a copy of the entire genome. 3.Once accomplished, the cell will physically divide to produce two identical daughter cells 17 15

  27. The entire cell cycle will take different amounts of time depending of the organism. For example, cell division in the bacteria (e.g. Escherichia coli) can take as little as 20 minutes. In a single-celled yeast it takes 90-120 minutes . Cells in organs such as the heart do not divide in the adult, except in cases where disease or trauma causes damage. Cells in the nervous system and the brain do not divide after birth, which is why an injury to the spine is usually irreversible. Hair, skin, fingernails, taste buds, and the stomach's protective lining are replaced constantly and at a rapid rate throughout our lives reproduce every 15-30 days 18 16

  28. Interphase: This part if the cells life cycle occupies most of the cells "life". The mitosis portion of the cycle may last only 10 - 20 hours while some cell can live for days or weeks. Mitosis Notes 19

  29. Parts of Interphase: G1phase: This part of the cell cycle is where the cell spends most of its life. This is the time when the cells are performing their assigned tasks. At some point in the cycle something triggers the cell to begin a cell division event. There are many stimuli which can cause the cell to require a cell division: - To replace dead or dying cells, - To produce more cells (growth and development) - Reproduction, i.e. to increase the number of unicellular organisms. 20

  30. S-phase: This is known as the synthesis phase. Here the DNA molecules are copied or replicated, therefore we go from single stranded DNA in G1 phase to double stranded DNA in G2. . 21

  31. G2 Phase The cell is preparing for the actual division events For example tubulin the protein of which microtubules are created is synthesized. This tubulin will be used to manufacture the microtubules of the spindle apparatus (fibers) in prophase of mitosis. G2 completes interphase now the cell is prepared for mitosis 22


  33. Animated Mitosis Cycle • Interphase • Prophase • Metaphase • Anaphase • Telophase & Cytokinesis Flip Book

  34. Interphase occurs before mitosis begins • 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 CELL MEMBRANE Nucleus Cytoplasm

  35. Interphase Plant Cell Animal Cell Photographs from:

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

  37. Prophase Plant Cell Animal Cell Spindle fibers Centrioles Photographs from:

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

  39. Metaphase Plant Cell Animal Cell Photographs from:

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

  41. Anaphase Plant Cell Animal Cell Photographs from:

  42. Telophase 4th step in Mitosis • Two new nuclei form. • Chromosomes appear as chromatin (threads rather than rods). • Mitosis ends. Nuclei Nuclei Chromatin

  43. Telophase Plant Cell Animal Cell Photographs from:

  44. Cytokinesisoccurs after mitosis • Cell membrane moves inward to create two daughter cells – each with its own nucleus with identical chromosomes.

  45. Animal Mitosis -- Review

  46. Plant Mitosis -- Review

  47. The only difference… Both plant and animal cells go through mitosis, BUT during TELOPHASE plant cells have a cell plate and animal cells have a cleavage furrow.

  48. Today in Biology Homework: Mitosis Worksheet Due Monday QUIZ MONDAY Week #2 Quarter 2 (10/23&24) Biology Learning Goal: Overview of chapter 6 – Genes, DNA, Chromosomes and chromatids Warm Up Question: Reflection turn in! What are spindle fibers? What is a centriole? What is a centromere? Fact of the Day When you die your hair still grows for a couple of months. That is why ghosts and scary creatures have long hair. • To Do Today: • Mitosis flip book • Mitosis worksheet – homework due Monday

  49. Cell Cycle Mitosis Flip Book 19

  50. Overview of Mitosis