Mitosis, Significance to unicellular and multicellular organisms, Chromosomes

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Mitosis, Significance to unicellular and
multicellular organisms, Chromosomes
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Significance of cell reproduction to
multicellular unicellular organisms
1. Unicellular reproduce by cell division. Also
called binary fission.
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2. Multicellular- processes of growth and repair
upon cell division, also the production of sex
cells.
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Describe chromosomes 1. Carriers of genetic
material found in nucleus 2. Made up of DNA 3.
Information is copied and passed to future
generations
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4. Usually exist as chromatin a. long, winding
strands which condense into chromosomes
before dividing 5. Human chromosome number
is 46 in body cells, 23 in sex cells
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The Cell Cycle

• 1. The cell cycle is a sequence of growth and
  division of a cell
• Made up of 2 distinct stages
• A. Interphase growth period where DNA is copied
• B. Mitosis dividing period producing 2 new cells

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Interphase
7 Hours DNA synthesis
11 Hours Rapid growth, centrioles replicate
3 Hours Growth final prep
P
M
T
A
Mitosis-1 hour
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Interphase- the first part of the cell cycle

1. Also called the resting stage
2. Cells make ATP
3. The cell repair themselves
4. Make proteins
5. Make new organelles
6. Copying new chromosomes(DNA)

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Mitosis
Mitosis is the division of the cytoplasm followed
by cell division. There are 4 stages of mitosis.
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Prophase

• The following events occur
• Chromatin coils to form short rods
• The 2 copies (chromatids) join to form
  chromosomes- held together by centromere
• Nuclear membrane disappears

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4. Centrioles move to opposite ends of the
cell 5. Spindle forms-helps pull chromosomes
apart are attached to centrioles
centrioles
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Metaphase

1. Chromosomes attach to spindle fibers
2. Chromosomes line up in the middle of the
   cell(equator).

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Anaphase

1. Centromeres split apart
2. Chromatids pairs split apart and begin to move to
   opposite ends(poles).

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Telophase

1. Chromatids reach opposite poles.
2. Chromatids begin uncoiling to form chromatin
   again
3. Spindle breaks down
4. Nucleolus and nuclear membrane reappear
5. Plasma membrane begins to pinch in

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Division of Cytoplasm-cytokinesis
In plants- the cell plate forms down the equator
of the cell
In animals-the cell pinches in along the equator
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Quiz 1 Mitosis
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• The sequence of events of cell growth division
  is called __________.
  a. Mitosis cycle b. cell cycle c. division
  cycle
• 2. __________ is when the cell prepares itself by
  copying DNA, repairing itself making new
  organelles.
  a. Metaphase b. prophase c.
  interphase d. telophase
• 3. Name the phase in which chromosomes are lined
  up at the equator.
  a. Anaphase b.
  telophase c. cytokinesis d.metaphase
• As the cytoplasm divides, what forms in plants
  down the equator of the cell?
  a. chromatids b. chromosomes c. cell plate

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5. Identify the correct phase of the cell cycle
mitosis.
a. interphase, prophase,
metaphase, anaphase, telophase b. prophase,
metaphse, interphase, anaphase, telophase c.
telophase, metaphase, anaphase, interphase,
prophase d. telophase anaphase, metaphase,
prophase, interphase