CELL GROWTH

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CELL GROWTH
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Limits to Cell Growth

• The larger a cell becomes, the more demands the
  cell places on its DNA
• Larger cells have more difficulty functioning
  efficiently
• Ratio of surface area to volume p 243

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Worksheet 10.1
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Mitosis and Cell Division
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CELL REPRODUCTION

• Chromosomes
• Chromatin
• DNA and protein
• Double helix
• Coiled
• Chromatids
• Karyotype
• Set
• 46 / 23

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CELL REPRODUCTION

• Diploid (2n)
• Haploid (n)
• Sex chromosomes
• X, Y XX or XY

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Prophase
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Mitosis

• Mitosis (M phase)
• Prophase
• Mitosis begins
• Chromosomes become visible
• Nuclear envelope breaks
• Spindle fibers appear
• Metaphase
• Chromosomes attach to spindle fibers
• Line up in middle of cell

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Anaphase
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MITOSIS CELL DIVISION

• 3. Anaphase
• Chromatid separates from twin
• Move to opposite pole
• Spindle fibers break down
• 4. Telophase
• Each side with set of chromosomes
• Nuclear membrane appears
• Chromosomes uncoil

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MITOSIS CELL DIVISION

• Cell Division
• Cytokinesis (C phase)
• Cytoplasm pinched in half
• End product two cells
• Cell Cycle
• Cell spends most of time growing
• 18 to 24 hrs.

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MITOSIS CELL DIVISION

• Interphase
• G1 phase (first gap)
• intense growth
• b. S phase (synthesis)
• precise copy of DNA in all chromosomes
• Remain attached at centromere
• c. G2 phase (second gap)
• duplicating organelles
• 2. Mitosis
• 3. Cytokinesis

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Worksheet 10.2
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CONTROLLING CELL CYCLE

• Cyclins
• S-cyclin
• Stimulates DNA replication
• M-cyclin
• Trigger mitosis
• Growth Factors
• Proteins, supervise cycle

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CANCER

• Defective controlling mechanism
• Grow / divide without restraint
• Tumor
• Benign - Harmless
• Malignant - Cancerous
• Mutation
• Change in gene
• Smoking, UV, etc.

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Worksheet 10 Cell Growth and Division
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MEIOSIS

• Gamete
• Reproductive cell
• Egg
• Sperm
• Haploid
• 23 chromosomes

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MEIOSIS

• Chromosome number into half
• Chromosome into Chromatids
• 4 (n) cells
• Sperm
• Four cells develop heads and tails
• Egg
• Three die, one matures

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MEIOSIS

• Crossing-over
• Exchange of segments of DNA
• Each chromosome with genetic material of parent