After viewing this program you will be able to

1
Cell Division

• After viewing this program you will be able to
• Name the major phases of a cells life cycle.
• Describe the primary characteristics involved in
  each phase of a cells life.

2
Cell Division The Formation of New Cells

3
Cell Division

• In order for the total number of cells to
  increase and for an organism to grow, the cells
  must undergo cell division.

4
Parent and Daughter Cells

• During cell division, one cell divides into two
  cells. Each new cell, called a daughter cell is
  identical to the parent cell.

5
Stages of Development

• The life cycle of a cell is divided into a series
  of stages or phases

6
Interphase
The phase in which the cell spends the majority
of its life. During this phase, the cell is
performing its normal life functions.
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Interphase

• Example
• Red Blood Cells
• ??carrying oxygen

8
Interphase

• The cell is also preparing for division by
  replicating its DNA and increasing its size.
• The cells chromosomes appear in a tangled form
  known as chromatin.

Chromatin
9
Mitosis

• The actual process of cell division is divided
  into 4 steps or phases.
• Prophase
• Metaphase
• Anaphase
• Telophase

10
Prophase

• Chromatin appears as rodlike bodies known as
  chromosomes in the nucleus.

Each chromosome has made a copy of itself.
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Prophase

• These chromosomes are called sister chromatids
  and are joined by a central part called a
  centromere.

12
Prophase

• During this phase a spindle begins to form a
  bridge between opposite ends of the cell.
• Near the end of this phase, the nuclear membrane
  and nucleolus also begin to disappear from view.

13
Metaphase

• The chromosomes prepare for division by lining
  up along a center line of the cell, referred to
  as the equator.

They are attached to the spindles by their
centromeres.
14
Anaphase

• The chromosomes divide at the centromere and
  allows the sister chromatids to separate from one
  another.

15
Telophase

• The chromosomes reach the opposite ends of the
  cell.
• The nuclear membrane and nucleolus begin to
  reappear.

16
Cytokinesis

• The cytoplasm is pinched off and divided into two
  nearly equal parts.
• Each part contains a nucleus with identical
  chromosomes.
• A new cell membrane and in plant cells, a cell
  wall also forms around the two new cells.

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Interphase Returns

• The process of cell division is now over. Two
  daughter cells have formed, each having the same
  number and kind of chromosomes as the original
  parent cell.

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Chromosome number

• The number of chromosomes in any organism varies
  from species to species.

19
Interphase

• In multicellular organisms such as humans, cell
  divisions take place millions of times as an
  organism grows and develops or replaces dead or
  injured cells.
• The cell returns to the phase before cell
  division. It is busy performing its normal
  duties and making copies of DNA available for the
  next time it will divide.

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Mitosis and Cytokinesis

• Although cell division is broken down into the
  steps previously discussed, it really occurs in a
  smooth, continuous process.
• Double click to
• watch as the
• entire process
• unfolds.

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Quiz Yourselfclick on an answer to check

• 1. The first stage of mitosis when chromosomes
  become visible is called..
• A. anaphase
• B. prophase
• C. telophase
• D. metaphase

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Sorry, please review Metaphase...

• The chromosomes prepare for division by lining
  up along a center line of the cell, referred to
  as the equator.

They are attached to the spindles by their
centromeres.
go back
23
Sorry, please reviewTelophase...

• The chromosomes reach the opposite ends of the
  cell.
• The nuclear membrane and nucleolus begin to
  reappear.

go back
24
Sorry, please reviewAnaphase...

• The chromosomes divide at the centromere and
  allows the sister chromatids to separate from one
  another.

go back
25
CORRECT ANSWER !!
Next question
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Quizclick on the correct answer

• 2.Which of the following statements is NOT true
  about mitosis.
• A. A single cell produces 2 identical daughter
  cells
• B. The centromeres divide at Anaphase
• C. Interphase is the shortest portion of a
  cells life cycle

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CORRECT ANSWER !!
Next question
28
Oops, please reviewParent/Daughter cells
During cell division, one cell divides into two
cells. Each new cell, called a daughter cell is
identical to the parent cell.
go back
29
Oops, please reviewAnaphase...

• The chromosomes divide at the centromere and
  allows the sister chromatids to separate from one
  another.

go back
30
QuizClick on the correct answer

• 3. During interphase, which of the following
  occur ?
• A. The chromosomes appear as chromatin
• B. The cell increases its size
• C. The cell is performing its normal life
  functions
• D. All of the above

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CORRECT ANSWER !!
Next question
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NICE TRY !!Review the other parts of Interphase
The cell is also preparing for division by
replicating its DNA and increasing its size.
The cells chromosomes appear in a tangled
form known as chromatin.
Chromatin
go back
33
NICE TRY !!Review the other parts of Interphase
go back
34
QuizClick on the correct answer

• 4. The four phases of mitosis occur in the
  following order
• A. metaphase, prophase, telophase, anaphase
• B. prophase, metaphase, telophase, anaphase
• C. anaphase, prophase, metaphase, telophase
• D. prophase, metaphase, anaphase, telophase

35
CORRECT ANSWER !!
Good Job- Thanks for taking the time to review
Cell Division
Return to tutorial
36
Uh oh, please reviewMitosis

• The actual process of Mitosis is divided into
  four steps or phases
• Prophase
• Metaphase
• Anaphase
• Telophase

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