Chromosomes

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Chromosomes
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• Defined Tightly coiled DNA
• Forms during cell division
• New chromosomes created for new cells
• 2 Parts
• 1) Chromatids two identical parts of a
  chromosome
• 2) Centromere Joins chromatids together

Chromosomes
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Karyotype

• Defined Picture of an individuals chromosomes
• Identify sex chromosome defects
• Size of final pair identifies sex
• Same size XX female
• Different size XY male
• Normal human will have 46 chromosomes

Female
Male
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Diploid Cells

• Diploid Cells Cells with the full set of
  chromosomes
• Paired chromosomes
• Half of our chromosomes come from each parent (23
  from each parent)
• Somatic (non-sex) cells are diploid
• Created by mitosis
• Ex Skin, Muscle, Nerve, Blood Cells

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Humans have 46 total chromosomes. What is the
human diploid chromosome number?

• RememberDiploid total number of chromosomes
• Answer 46

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Humans have 46 total chromosomes. What is the
human somatic chromosome number?

• RememberSomatic cells are non-sex cells
• Somatic cells are diploid
• Diploid cells have the full set of
  chromosomes
• Answer 46

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Humans have 46 total chromosomes. How many
chromosomes are in brain cells?

• RememberBrain cells are non-sex cells
• Somatic cells are non-sex cells
• Somatic cells are diploid
• Diploid cells have the full set of
  chromosomes
• Answer 46

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Haploid Cells

• Haploid Cells Cells with ½ the total number of
  chromosomes
• Gametes (sex cells) are the only haploid cells
• Ex Sperm, Egg, Pollen
• Chromosome number is reduced by meiosis
• How do humans get 46 chromosomes?

Haploid sperm cell (23)
Haploid egg cell (23)
Diploid zygote (46)
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Humans have 46 total chromosomes. What is the
human haploid chromosome number?

• RememberHaploid half number of chromosomes
• Answer 23 chromosomes

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Humans have 46 total chromosomes. What is the
human gamete chromosome number?

• RememberGamete cells are sex cells
• Sex cells are haploid
• Haploid cells have ½ the set of chromosomes
• Answer 23

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Humans have 46 total chromosomes. How many
chromosomes are in female egg cells?

• RememberEgg cells are sex cells
• Sex cells are gametes
• Gamete cells are haploid
• Haploid cells have ½ the set of chromosomes
• Answer 23

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Down Syndrome Whats Wrong?

• Writing notation
• 1st total chromosome
• 2nd Sex chromosomes
• 3rd extra or missing
• Down Syndrome 47, XY, 21

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Turners Syndrome Whats Wrong?

• Write the notation for Turners Syndrome.
• 45, X, -23
• or
• 45, XO, -23

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Pataus Syndrome Whats Wrong?

• Write the notation for Pataus Syndrome.
• 47, XY, 13

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Klinefelters Syndrome Whats Wrong?

• Write the notation for Klinefelters Syndrome.
• 47, XXY, 23

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Rat Karyotype

• What is the diploid chromosome number?

42
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Rat Karyotype

• What is the haploid chromosome number?

21
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Rat Karyotype

• How many chromosomes would be in somatic cells?

42
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Rat Karyotype

• How many chromosomes would be in brain cells?

42
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Rat Karyotype

• How many chromosomes would be in gamete cells?

21
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Rat Karyotype

• How many chromosomes would be in egg cells?

21
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Rat Karyotype

• How many chromosomes would be in muscle cells?

42
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Rat Karyotype

• How many chromosomes would be in sperm cells?

21
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Rat Karyotype

• Is this a male or female rat?

male
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Quick Review

• Chromsomes are tightly coiled strands of DNA
• Diploid (somatic) cells contain the entire set of
  chromosomes
• Haploid (gametes) cells contain only ½ the total
  number of chromosomes