Cell Growth

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Cell Growth Division

• Mitosis

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Chromosomes

• Carry Genetic Information
• From One Generation of Cell
• To the Next Generation of Cells
• Made Up Of
• DNA Protein

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Chromosomes

• Every species Has
• A Specific Number
• Fruit Fly's 8
• Carrots 18
• Humans 46
• Giraffe 30
• King Crab 208

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Chromosomes

• Not Visible Except During Division
• Well Before Cell Division They Duplicate

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Chromosomes

• Chromatids
• Just Before Division Chromosomes Condense Into
  Compact, Visible Structures Called Chromatids
• Centromere
• Each Chromosome Has Two, Identical Chromatids
  Connected By A Centromere

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Chromosomes
Chromatid A
Copy of Chromatid A
Centromere
Kenitophore
Microtubules or Spindle Fibers
Copy of Chromatid A
Chromatid A
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The Cell Cycle

• Key Concept
• During The Cell Cycle
• A Cell Grows
• Prepares For Division
• Divides To Form Two Daughter Cells
• Each Daughter Cell Then Begins The Cycle Again

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Cell Cycle
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Interphase

• Time In-Between Cell Divisions

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Cell Division or M phase
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Events Of The Cell Cycle

• Interphase
• May Be Quite Long
• Divided Into 3 Parts
• G1
• S
• G2

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The 3 Parts of Interphase

• G1 Phase
• Cell Performs Its Primary Function
• Cell Grows In Size
• Synthesize New Proteins Organelles

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The 3 Parts of Interphase

• S Phase (Synthesis Phase)
• Chromosomes Are Replicated
• Once This Phase Begins The Cell Must Complete
  Division

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The 3 Parts of Interphase

• G2 Phase
• Organelles Proteins Required For Mitosis Are
  Produced
• Cell Is Now Ready To Enter
• M Phase (Mitosis)

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Mitosis

• Key Concept
• Biologists Divide The Events Of Mitosis Into Four
  Phases
• Prophase
• Metaphase
• Anaphase
• Telophase

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Prophase

• 1st Longest
• Phase
• Chromosomes Become Visible
• Centrioles Separate Take Up Position On
  Opposite Sides Of The Nucleus
• Spindle Begins To Form

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Prophase

• In Animals
• Spindle Fibers Attach To Centromere On Each
  Chromatid
• In Plants
• No Centrioles, Spindle Fibers Still Form From
  Centrosomes To The Centromeres

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Late Prophase

• Nucleolus Disappears
• Nuclear Envelope Breaks Down

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Metaphase

• Short
• Just A Few Minutes
• Chromosomes Line Up Across Center Of The Cell
• Microtubules Connect The Centromere To The Poles
  Of The Spindle

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Anaphase

• Centromeres Separate
• Sister Chromatids Separate
• Each Set Of Chromosomes Pulled To Their Poles

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Telophase

• Chromosomes Disperse
• New Nuclear Envelopes Form
• Spindle Breaks Apart
• Nucleolus Reforms

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Cytokinesis

• There Are Now Two Nuclei In One Cell
• Cytokinesis Is The Division Of The Cytoplasm Into
  Two Cells
• The Cell Membrane Is Drawn Inward Until The Cell
  Pinches Into Two Equal Parts

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Cytokinesis In Plants

• A New Cell Plate Forms
• In The Middle Of The Cell
• Which Attaches To, And Becomes Part Of, The Cell
  Wall

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