Ch. 10 : Cell Division and Growth

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Ch. 10 Cell Division and Growth
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10-1 Cell Reproduction

• Why do cells divide?
• How is DNA packaged in the nucleus?
• How do cells prepare for division?
• Cells are busy making more cells.
• The reproduction of cells allows
• you to grow and heal.

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Cell reproduce to

• Control cell size (many smaller cells are more
  efficient than one large cell)
• Surface area to volume ratio for supplies,
  proteins and control by nucleus
• Make new cells
• Growth in multicellular organisms
• Development
• replace
• Repair
• Wounds
• Reproduce
• If you are single celled

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• 10-1 CHROMOSOMES
• DNA is a long thin, coiled molecule.
• DNA is a chemical
• DNAs job is to store and transfer information
• DNA is made of nucleotides, each human cell has
  DNA totaling 6 billion nucleotide pairs!

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Chromosome structure

• DNA in a eukaryotic nucleus is thin and uncoiled
  it is called chromatin. Chromatin is available
  for the cell to use as information
• When the eukaryotic cell divides the DNA must be
  copied, packaged and move to new nuclei. The
  packaged format is called chromatids and
  chromosomes. This is only for cell division.

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Chromosome structure

• Prokaryotes
• One chromosome
• Circular
• No nucleus
• plasmids

• Eukaryotes
• Many (humans have 23 pairs or 46)
• Linear
• Inside nuclear membrane
• DNA is copied into RNA

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DNA

• DNA is a long thin chemical chain, made of
  nucleotides, in the form of a double helix.
• DNA wrapped around protein is called chromatin
  and chromatin coiled into visible threads is a
  chromosome.
• After DNA copies each part is called a chromatid
  and they travel together connected at a structure
  called a centromere.

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Chromosome numbers

• Normal humans have 23 pairs of chromosomes ( 46
  total).
• 22 pairs are autosomes, regular chromosomes
• The 23rd pair is called the sex chromosomes and
  determines your gender
• X X means a female
• X Y means a male

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Preparing for division

• Prokaryotes Binary Fission
• Copy one chromosome
• Membrane indents
• Wall forms
• 2 genetically identical cells
• Eukaryotes Mitosis
• S of interphase (Interphase G1, S and G2)
• All chromosomes are copied
• Nuclear membrane dissolves
• Other organelles and structures are copied and
  formed
• Then enters MITOSIS which is nuclear division

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Vocabulary

• Homologous chromosomes ? are the two copies of
  each autosome, same size and same shape and same
  genes in the same locations.
• Karyotypes ? pictures of your chromosomes from a
  microscope (WBC) and arranged in order from
  longest to shortest.

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Karyotype
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More vocabulary

• Diploid cells/ diploid number ? cells that
  contain both chromosomes from each homologous
  pair. ( 23 pairs, or 46 total, in humans) . All
  of our cells that are NOT egg or sperm.
• Haploid cells/ haploid number ? cells that only
  contain one from each pair for 23 total
  chromosomes. These cells would include eggs,
  sperm and cells like pollen and spores in plants
  and fungi. They are reproductive cells, as
  opposed to body (somatic) cells.

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10-2 Mitosis

• What are the phases of the eukaryotic cell cycle?
  
• What are the stages of mitosis?
• How does cytokinesis occur?
• The events of the cycle
• ensure that new cells
• will be just like the old cell.

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10-2 Eukaryotic Cell Cycle

• Binary fission ? the division of prokaryotic
  cells (bacteria) into two new cells.
• Mitosis ? cell division in eukaryotic cells that
  results in two new, identical, diploid cells.
  (skin cell makes new skin cells)
• Meiosis ? division in specialized eukaryotic
  cells that reduces the number of chromosomes to
  haploid - creating reproductive cells.

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Mitosis Review

• Steps of Mitosis
• Interphase grow, copy DNA
• Prophase chromosomes and structures visible
• Pro-metaphase spindle complete
• Metaphase chromosomes aligned at equator
• Anaphase chromosomes and copies separate and
  move
• Telophase new nuclei form
• Cytokinesis cytoplasm and organelles are
  divided. Cell plate is formed in plant cells

xxxx
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Mitosis occurring in root cells of onion
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10-3 Regulation
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8-3 MEIOSIS

• reduction division
• Produces reproductive cells, that are haploid and
  are generically called gametes
• Cells still do Interphase, one and only one time
  to copy the chromosomes
• Then they divide twice, producing four cells.

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Meiosis terminology

• Synapsis ? pairing of homologous chromosomes that
  only occurs during meiosis. Chromsome 1 and its
  copy chromatid and the OTHER chromosome 1 and
  its copy chromosome pair up. Creating a group of
  four
• Tetrad ? group of four. Pairs of pairs of
  chromosomes.
• Crossing over? some times adjacent pieces of
  chromsomes break and re-align with another part
  of the tetrad.

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Terminology continued

• Genetic recombination ? as a result of crossing
  over eggs and sperm can give offspring different
  combinations than that of the parent.
• Grandma has brown hair and blue eyes
• Grandpa has blonde hair and brown eyes
• Mom has brown hair and brown eyes but could give
  the child an egg with the information for
• Child blonde hair and brown eyes

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End of vocabulary

• Independent Assortment ? each chromsome pair goes
  to the gametes without the influence of the other
  chromosomes can get grandmas info. for 4 and
  grandpas info for 17.
• Spermatogenesis process where specialized cells
  create sperm
• Oogenesis process where specialized cells make
  ova (eggs)
• Asexual reproduction offspring are produced by
  one parent through mitosis
• Sexual reproduction offspring are produced by
  union of egg and sperm. Requires meiosis.