Genes and Reproduction

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  • Created by: puntm003
  • Created on: 18-02-14 10:04
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  • Genes and Reproduction
    • Variation
      • Genetic Variation
        • Characteristics are similar to parents'
        • Animals and some plants get genes from their mother and father
        • This combination of genes from the parents means that except for identical twins no two of the species are genetically identical
      • Environmental Variation
        • The environment that species live in will cause differences between members of the same species
        • For example, losing your toes to frost bite or getting a sun tan
        • Any changes that have been caused by the conditions that a species live in is environmental variation
    • Genes, Chromosomes and DNA
      • Most cells in the body have a nucleus
        • The nucleus contains genetic material in the form of chromosomes
      • The human cell nucleus contains 23 pairs of chromosomes
        • The nucleus contains genetic material in the form of chromosomes
        • Chromosomes are always in pairs, one from each parent
      • A gene is a short length of the chromosome
      • The DNA is coiled up to form the arms of the chromosome
        • A gene is a long length of DNA
    • Sexual reproduction
      • Genetic information from two organisms is combined to produce offspring
      • The offspring are genetically different to either parent
      • The mother and father produce gametes
        • Egg and sperm cells in animal
      • Each gamete contains 23 chromosomes- half the number in a normal cell
      • The egg and sperm fuse together to form a cell with the full number of chromosomes
        • The name of the fertilized egg cell is zygote
        • Sperm
          • Mitochondrion
            • Releases energy to allow the tail to move
            • Mitochondria
              • A structure within a cell to allow aerobic respiration to take place
          • Acrosome
            • Enzymes at the front of the sperm that allow it to digest the jelly layer around the egg
    • Asexual Reproduction
      • One parent
      • No genetic variation between parent and offspring
        • The offspring are clones
      • X-shaped chromosomes have 2 identical halves
      • The DNA replicates itself to from two identical cells
  • Within a cell you have 23 pairs of chromosomes
    • Within a chromosome you have different genes
      • A gene is a long length of DNA
    • Genes, Chromosomes and DNA
      • Most cells in the body have a nucleus
        • The human cell nucleus contains 23 pairs of chromosomes
          • Chromosomes are always in pairs, one from each parent
        • A gene is a short length of the chromosome
        • The DNA is coiled up to form the arms of the chromosome

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