SEXUAL REPRODUCTION

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SEXUAL REPRODUCTION

• Quiz 6B

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sexual reproduction

• the joining of haploid gametes to form a diploid
  zygote, which develops into a new individual
• each offspring receives genes from both its
  parents
• get genetic variety

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Information about genes
most organisms have 2 genes for every trait
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Information about genes
genes are parts of chromosomes
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Information about genes
most genes come in pairs
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Information about genes
most chromosomes come in pairs
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Diploid

• having 1 pair of each type of chromosome in an
  organism
• have 2 of every kind of chromosome
• symbol is 2n

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Haploid

• a cell that has only 1 chromosome of every pair
• symbol is 1n

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Diploid vs Haploid
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Normal human cells have 23 pairs of chromosomes
which is a total of 46 chromosomes.
Human diploid number is 46
Human haploid number is 23
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Diploid Haploid Examples
Haploid Diploid
Honey bee 16 32
Crayfish 100 200
Rabbit 22 44
Watermelon 11 22
Corn 10 20
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Meiosis

• the process whereby 1 diploid cell forms haploid
  cells (gametes)
• a dividing process during which the of
  chromosomes is cut by 1/2 in each resulting cell
• also called reduction division

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Meiosis
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Gamete

• a cell that contains only 1 of each type of
  chromosome found in an organism
• a reproductive cell
• in order to form a haploid cell (gamete)- meiosis
  occurs
• in most organisms meiosis produces 1 of 2 types
  of gametes

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2 types of gametes

• Ova (singular-ovum) - female gametes usually
  larger than the male gamete and does not have
  that power to move itself
• Sperm - male gametes usually smaller than ova,
  but they have some means of moving themselves

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2 types of gametes
ovum
sperm
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Spermatogenesis
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Oogenesis
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Where are gametes formed?
In reproductive organs

• Testes male reproductive organs
• Ovaries female reproductive organs

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Fertilization
the formation of a zygote from the union of 2
gametes
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Zygote
a diploid cell formed by the union of 2 gametes