Mitosis and Meiosis Lesson 3.2 : Cell Division is part of the cell cycle Lesson 4.3: Meiosis is a special form of cell division - PowerPoint PPT Presentation

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Mitosis and Meiosis Lesson 3.2 : Cell Division is part of the cell cycle Lesson 4.3: Meiosis is a special form of cell division

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Mitosis and Meiosis Lesson 3.2 : Cell Division is part of the cell cycle Lesson 4.3: Meiosis is a special form of cell division 3.2: The cell cycle includes ... – PowerPoint PPT presentation

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Title: Mitosis and Meiosis Lesson 3.2 : Cell Division is part of the cell cycle Lesson 4.3: Meiosis is a special form of cell division


1
Mitosis and Meiosis Lesson 3.2 Cell Division
is part of the cell cycleLesson 4.3 Meiosis is
a special form of cell division
2
3.2 The cell cycle includes interphase and cell
division
  • All living things live, grow, reproduce, and die
    in a process called a life cycle.
  • Cell Cycle the normal sequence of development
    and division of a cell.
  • Cell cycle consists of two main phases
    interphase mitosis/cytokinesis

3
Interphase
  • Part of the cell cycle during which a cell is not
    dividing.
  • The cell grows to about twice the size it was
    when first produced.
  • The cell engages in normal activities
    transporting materials in and transporting wastes
    out cellular respiration occurs providing energy
    to the cell
  • It duplicates its DNA exactly

4
Cell Division Phase
  • Mitosis part of the cell cycle during which the
    nucleus divides
  • Cytokinesis the divison of the parent cells
    cytoplasm occurs immediately after mitosis
  • Results the original (parent cell) cell splits
    into two genetically identical daughter cells

5
Mitosis Steps
  1. Prophase Nuclear membrane disappears
    Chromosomes form
  2. Metaphase Chromosomes line up in the middle of
    the cell
  3. Anaphase Chromosome pairs split resulting in two
    separate identical chromosomes
  4. Telophase/Cytokinesis nuclear membrane forms
    around each group of chromosomes Cytoplasm
    divides to form two identical cells

6
  • Nuclear membrane disappear Chromosomes form
  • Chromosomes line up in the middle of the cell
  • Chromatids split resulting in two separate
    identical chromosomes
  • nuclear membrane forms around each group of
    chromosomes Cytoplasm divides to form two
    identical cells

7
4.3 Meiosis is necessary for sexual reproduction
Making a new ME
  • Diploid cell any cell that contains the full
    number of chromosomes (human body cells)
  • Gametes cells that contain half of the usual
    number of chromosomes (one chromosome from each
    pair) haploid cells (egg cell sperm cell)
  • Fertilization process that takes place when a
    sperm and egg cell combine to form one new cell
  • Meiosis a special kind of cell division that
    produces haploid cells
  • Meiosis only takes place in the reproductive
    tissues of an organism

8
Meiosis I
  • Before it begins, the chromosomes of the parent
    cell are copied (twice as many chromosomes as
    usual
  • Prophase 1 Duplicated chromosomes pair up and
    nuclear membrane disappears
  • Metaphase 1 Chromosome pairs line up in the
    center of the cell
  • Anaphase 1 Two copies of one homolog are pulled
    apart
  • Telophase 1 Cytokinesis a new cell membrane
    forms at the center of the cell and the cytoplasm
    is separated to form 2 daughter cells.

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10
Meiosis II
  • Prophase 2 There is one copy of each chromosome
    (two chromatids) attached together
  • Metaphase 2 Each chromosome lines up along each
    cells center
  • Anaphase 2 Each chromosome separates (into two
    identical chromatids) and are pulled to opposite
    poles on each cell
  • Telophase 2 and Cytokinesis A new cell membrane
    forms splitting the cytoplasm to form four
    haploid cells
  • In male organisms, these gametes become sperm
  • In female organisms, at least one of the cells
    becomes an egg. The rest dissolve back into the
    organism.

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12
Meiosis and Mitosis differ in some important ways
  • Meiosis
  • Haploid Cells (gametes)
  • Two cell divisions
  • Chromosomes are copied before the first cell
    division but not the second
  • Daughter cells produced contain only half the
    genetic material of the parent
  • Mitosis
  • Diploid Cells (human body cells)
  • One cell division
  • Chromosomes are always copied before division
  • Daughter cells produced contain exactly the same
    genetic material as the parent

13
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