Cell Division: sexual and asexual reproduction

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Cell Division sexual and asexual reproduction
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Sexual vs. Asexual

• Sexual reproduction
• Occurs in eukaryotes (multicellular organisms)
• Asexual reproduction
• MOSTLY occurs in prokaryotes (unicellular)
• FEW multicellular organisms use asexual
  reproduction

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Asexual Reproduction
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Asexual Reproduction

• One organism produces one or more new organisms
  that are identical to itself and that live
  independently of it
• Three types
• Binary fission
• Budding
• Regeneration

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1. Binary fission

• Form of asexual reproduction
• Occurs in prokaryotes (bacteria)
• Parent organism splits into two genetically
  identical cells

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2. Budding

• Occurs in eukaryotes and prokaryotes
• A bud forms from the parents cell. The bud grows
  until it forms a complete new organism with the
  same genetic material

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3. Regeneration

• Some animals, when cut in pieces will grow into
  many animals.

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Sexual Reproduction

• Production of offspring from two parents.
• Sperm Egg Zygote
• 23 23 46
• Haploid haploid diploid

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Sexual reproduction

• Plants growing from seeds and animals growing
  from eggs are examples of organisms that
  reproduce through sexual reproduction

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Categorize
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Compare and Contrast

• Comparing and contrasting sexual and asexual
  reproduction
• Venn diagram
• Double bubble
• Comparison chart
• USE PAGES 88-92 in Cells and Heredity

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2. Spores

• Molds fungi form a copy of the DNA and a
  protective wall around it.
• Billions are released not all survive.

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4. Vegetative Propogation

• When plants send out runners to look for light.

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Meiosis

• The production of gametes.
• Each new cell has ½ the chromosomes of the parent
  cell.
• Parent cell diploid (2n) ex. 46 chromosomes
• Gamete haploid (n) ex. 23 chromosomes

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Prophase I

• Chromatin coils to chromosomes.
• Homologous chromosomes (a pair of chromosomes,
  each having genes for the same trait) pair up.
• Crossing over homologous chromosomes exchange
  genes, increasing genetic variety.

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Metaphase I

• Homologous chromosomes line up on the equator of
  the cell.

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Anaphase I

• Homologous chromosomes are separated.

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Telophase I Prophase II

• Cell divides into 2 cells
• Each cell has ½ the chromosomes.
• Identical sister chromatids are still together

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Metaphase II

• Sister chromatids line up on the equator of each
  cell.

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Anaphase II

• Sister chromatids are separated in each cell.

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Telophase II

• Each cell divides into 2 new cells.
• 4 sperm or eggs have been created, each having ½
  the original amount of DNA.

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Differences

• Sperm 4 sperms are made from each parent cell.
• Egg 1 egg is formed, the 3 other cells die.
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Sex Determination

• Autosomes 22 pairs in humans code for body
  parts.
• Sex chromosomes 1pair code for sex
• XX female
• XY male
• Karyotype a picture of the chromosomes

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Sex Determination

• Which sperm gets to the egg first determines the
  sex.
• Some sperms have X sex chromosome some sperms
  have Y sex chromosome.
• Female always gives an X.

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Nondisjunction

• When the chromosomes do not separate properly
  during meiosis.
• Trisomy - the offspring receive too many
  chromosomes.
• Monosomy the offspring receive too few
  chromosomes.

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Trisomy

• Downs Syndrome trisomy 21 large tongue,
  short neck, mental retardation
• Klinefelters Syndrome XXY long arms legs,
  breasts, hip fat, bad decision maker

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Trisomy Monosomy

• XYY Syndrome higher than usual testosterone
• Turners Syndrome X webbed neck, no puberty,
  elbow deformity