Tuesday, August 30, 2011

3.24 Mitosis






  • Mitosis- Cell division - Growth - Increase in cell count
  • Cell - 46 chromosomes - diploid number - abbreviation : 2N
    • Humans: 46
    • Cats: 38
  • The cell divides in two that contains a diploid nucleus - identical 'twins' - Exact copy of the original - Called DNA replication
    • Same number of chromosomes
    • Same set of chromosomes
  • The two copies are held together by the 'centrometre' - Makes pair of 'Chromatids'
  • DNA replication happens inside nucleus - process is known as: Cell Cycle
  • Prophase - When the nucleaus starts breaking down and the chromosomes become visible as a pair of chromatids in the process of Mitosis begins
    • Protine molecules create spindle grow where the chromatids move and join on to
    • Metaphase - Spindle fibers + Chromatid attach through the centrometre
    • Anaphase - The fiber + Chromatid shortens and gets pulled apart - moves away from another - becomes separated pars of chromatids
    • Telophase - Nucleus begins to regorm around the chromosome of both cells (Last phase)
  • Cytokinesis - when the cell splits into 2 - NOT PART OF MITOSIS
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Tuesday, August 23, 2011

3.16 DNA and Genetic information


3.16 DNA and Genetic information




  • A chromosome has thousands of genes that when expanded and magnified, you would find 2 helix that are parallel- When we zoom in again, we see what holds the strands of the helix together, the two sections 
  • 'Sugar Phosphate ?Backbone' is what holds both helixes together
  • Molecules called bases that hold both helixes together
    • Adenine (A)
    • Thymine (T)
    • Cytosine (C)
    • Guanine (G)

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3.14&.15 Chromosomes


3.14 Chromosomes




  • Cell Nucleus > Chromosomes >  DNA (Deoxyribonucleic acid) > Genes ( Section)
  • DNA shape: Double helix
  /\
 /_\
/__\
\__/
 \_/
  \/
  /\
 /_\
/__\
\__/<-- Genes ---------> Characteristics Ex: Petal color/Blood type
 \_/      (Neucleus)       (Protein (Cytoplasm))
  \/
  /\
 /_\
/__\
\__/
 \_/
  \/
  • 1 Chromosome = 1000s of genes
  • Genes carry instructions for the build of a protein 
  • Protein carries characteristics of an individual ex: Blood
  • Different spices have different numbers of chromosomes 
    • Cat: 38
    • Chicken: 78
    • Chimps: 42
    • Humans: 46
  • Chromosomes work in pairs (homologous pairs)
    • Nature: Based on length of the chromosones
  • Homologous Loci = the sames as the other paired with it ( 2 versions of one charactaristic per gene (alleles))
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3.14 Chromosomes


3.14 Chromosomes




  • Cell Nucleus > Chromosomes >  DNA (Deoxyribonucleic acid) > Genes ( Section)
  • DNA shape: Double helix
  /\
 /_\
/__\
\__/
 \_/
  \/
  /\
 /_\
/__\
\__/<-- Genes 
 \_/
  \/
  /\
 /_\
/__\
\__/
 \_/
  \/
  • 1 Chromosome = 1000s of genes
  • Genes carry instructions for the build of a protein 
  • Protein carries characteristics of an individual ex: Blood
  • Different spices have different numbers of chromosomes 
    • Cat: 38
    • Chicken: 78
    • Chimps: 42
    • Humans: 46
  • Chromosomes work in pairs (homologous pairs)
    • Nature: Based on length of the chromosones
  • Homologous Loci = the sames as the other paired with it ( 2 versions of one charactaristic per gene (alleles))
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