Cell Reproduction

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Cell Reproduction

• Chromosomes

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Eukaryotic Chromosomes

• Chromosomes in eukaryotic cells
• coiled DNA
• Made of DNA and proteins

academy.d20.co.edu/kadets/ lundberg/dna.html
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Chromosome Structure

• Histones -
• DNA wraps around protein
• Help maintain shape
• Pack it tighter

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www.geneinformation.org/ chromosomepicture.htm
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Chromosome Structure

• Chromatin-less tightly coiled chromosomes
  (prophase)

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• Centromere - holds cromatids together

Chromatids - two identical halves
www.micro.utexas.edu/.../bio304/
genetics/genetics.html
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Number of Chromosomes

• Adders tongue fern 1,262
• Carrot 18
• Cat 32
• Chimpanzee 48
• Dog 78
• Orangutan 48
• Earthworm 36
• Fruit fly 8

• Garden pea 20
• Gorilla 48
• Horse 64
• Human 46
• Plums 48
• Potatoes 48
• Lettuce 18
• Sand dollar 52

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• Sex Chromosomes
• Determine sex
• Carry other genes
• XX female
• XY male
• Humans have 46 chromosomes
• 44 autosomes
• 2 sex chromosomes

• Autosomes
• Carry genes

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Autosomes Diploid

• Diploid cells- 2 sets of chromosomes 2n

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Sex cells Haploid

• Gametes- sex cells (sperm and eggs)
• Haploid cells- contain one set of chromosomes
• 1n
• Sperm (1n) egg (1n) zygote (2n)

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www.uia.ac.be/u/bharding/Genetica/
Hoofdstuk1/begrippen.html
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Homologous pair Hold the same genes for the same
traits (hair color)
Chromosome with one chromatid
duplication
Nonsister chromatids
duplication
Sister chromatids
Paternal chromosome maternal chromosome
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Homologous chromosomes

• 2 copies of each
• Same size and shape
• Carry genes for same trait

admin.vmi.edu/ir/ dev/devthree.htm
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Karyotype

• photograph of the chromosomes in a dividing cell.