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After viewing this program you will be able to
Name the major phases of a cell’s life cycle.
Describe the primary characteristics involved in each phase of a cell’s life.
Cell DivisionCell Division
In order for the total number of cells to increase and for an organism to grow, the cells must undergo cell division.
Parent and Daughter Parent and Daughter
CellsCells During cell division, one cell divides into two
cells. Each new cell, called a daughter cell is identical to the parent cell.
Parent Cell
DaughterCell
DaughterCell
Stages of DevelopmentStages of Development
The life cycle of a cell is divided into a series of stages or phases
Interphase Interphase
The phase in which the cell spends the majority of its life.
During this phase, the cell is performing its normal life functions.
InterphaseInterphase
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
MitosisMitosis
The actual process of cell division is divided into 4 steps or phases.
Prophase
Metaphase
Anaphase
Telophase
ProphaseProphase
Chromatin appears as rodlike bodies known as chromosomes in the nucleus.
Each chromosome has made a copy of itself.
ProphaseProphase
These chromosomes are called sister chromatids and are joined by a central part called a centromere.
ProphaseProphase
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.
MetaphaseMetaphase
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.
AnaphaseAnaphase
The chromosomes divide at the centromere and allows the sister chromatids to separate from one another.
TelophaseTelophase
The chromosomes reach the opposite ends of the cell.
The nuclear membrane and nucleolus begin to reappear.
Cytokinesis 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.
Interphase ReturnsInterphase ReturnsThe 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.
Parent Cell
DaughterCell
DaughterCell
46
46
46
Human cells with 46 chromosomes
Chromosome numberChromosome number
The number of chromosomes in any organism varies from species to species.
Organism Chromosome Number
Cat 38
Dog 78
Horse 64
InterphaseInterphase
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.
Mitosis and Mitosis and CytokinesisCytokinesis
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.
Quiz YourselfQuiz Yourselfclick on an answer to checkclick 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
Sorry, please review Sorry, please review Metaphase…...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
Sorry, please reviewSorry, please reviewTelophase...Telophase...
The chromosomes reach the opposite ends of the cell.
The nuclear membrane and nucleolus begin to reappear.
go back
Sorry, please reviewSorry, please reviewAnaphase...Anaphase...
The chromosomes divide at the centromere and allows the sister chromatids to separate from one another.
go back
QuizQuizclick on the correct answerclick 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 cell’s life cycle
Oops, please review…Oops, please review…Parent/Daughter cells Parent/Daughter cells
go back
Parent Cell
DaughterCell
DaughterCell During cell
division, one cell divides into two cells. Each new cell, called a daughter cell is identical to the parent cell.
Oops, please reviewOops, please reviewAnaphase...Anaphase...
The chromosomes divide at the centromere and allows the sister chromatids to separate from one another.
go back
QuizQuizClick on the correct answerClick 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
NICE TRY !!NICE TRY !!Review the other parts of InterphaseReview 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
NICE TRY !!NICE TRY !!Review the other parts of InterphaseReview the other parts of Interphase
go back
Example
Red Blood Cells
ËË carrying oxygen
QuizQuizClick on the correct answerClick 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
CORRECT ANSWER CORRECT ANSWER !!!!
Good Job- Thanks for taking the time to review Cell Division Return to
tutorial