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Somatic Cellular Reproduction:
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The Cell Cycle and Mitosis
Cells that make up the “body” of an organism
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Why Should Cells Divide???
In Unicellular Organisms:
• Reproduction
In Multicellular Organisms:
• Maintain a favorable surface area to
volume ratio
• Maintain correct number of chromosomes
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Structures that contain the genetic
material
Chromosomes are composed of chromatin, a
tangled mass of DNA and proteins
The Full Number of
Chromosomes Found in all
Somatic Cells is the Diploid
Number (2N)
The Diploid Number
includes 2 of each
chromosome (a pair)
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Each Chromosome contains two identical
parts called “sister chromatids” attached at a
centromere
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The cycle of growth and division in all cells
Consists of Interphase and Mitosis
• Mitosis (M phase) is a period of cell division
• Interphase is a period of DNA replication and growth in
preparation for cell division
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The Cell Cycle
Protein Synthesis
Cell Division
Growth
DNA copies
itself
interphase
mitosis
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Growth and DNA synthesis
and Replication (G1, S, G2)
Longest period of Cell Cycle
Chromatin in nucleus
appears as mass of threadlike
structures
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Stages
of
Mitosis
Prophase - forward/before
Metaphase - change (metamorphosis)
Anaphase - backward
Telophase - end
Interphase - between (intermission)
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•Chromatin Condensed Into Visible Chromosomes
•Nucleolus Disappears and Nuclear Envelope Fragments
•Centrioles move to opposite sides of the cell
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•Chromosomes lined up on equatorial plate
•Spindle fibers attach at centromeres
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•Centromeres divide
•Sister chromatids pulled towards the poles
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•Spindles disappear and nuclear envelope returns
•Nucleolus returns
•Chromosomes unwind into chromatin
Animal Cell
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Plant Cell
Identify the Stages of Mitosis
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