Inheritance

Explains what you need to know for Biology 1 section 3 for for your exam.

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  • Created by: Owain
  • Created on: 02-01-13 17:31
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  • Inheritance
    • Chromosomes
      • Made up of DNA
        • DNA carries the code for putting the amino acids together in a protein
          • Different proteins give organisms different characteristics
      • Genes
        • Made up of DNA
          • DNA carries the code for putting the amino acids together in a protein
            • Different proteins give organisms different characteristics
        • Genes have different forms called ALLELES
        • Found in pairs inside the nucleus
      • Found in pairs inside the nucleus
    • Genetic terms
      • Genotype - This is the combination of alleles that an organism has.
      • Phenotype - The appearance of an organism caused by a gene
      • Allele
        • Genes have different forms called ALLELES
        • Homozygous - This is where 2 of the same allele has joined
        • Recessive - This is the allele that does not show itself in the organism unless there are 2 of them
        • Heterozygous - This is where 2 different alleles have joined
        • Dominant - This is the allele that shows itself in the organisms
    • Gametes
      • Sex cells - sperm and egg
      • Contains one allele of each gene
      • They only recieve half the number of chromosomes
        • When fertilisation occurs two gametes join to form a zygote with a full number of chromosomes and two alleles
          • Contains one allele of each gene
    • Gregor Mendel
      • His work
        • Used large numbers of pea plants in his experiments
        • He recorded his observations carefully
        • He repeated his experiment many times
        • He analyzed his results using statistics
        • deducted that characteristics are passed from generation to generation by factors passed on in gametes
      • Published his work in1866 and sent it to many universities but it was not recognised
        • His work was rediscovered in the early 20th century and scientists started to replicate his work
    • Genetic modification
      • This means taking genes and putting them into another organism and putting them in another organism
      • Herbicide resistant soya beans
        • Herbicide = Weedkiller
        • Herbicide resistant = Not killed by herbicides
        • Why? = Can spray a whole field and it will only kill weeds
        • Advantages
          • Less competition for space and nutrients
          • Soya beans grow bigger
          • Bigger yield
          • More food
          • More income for farmer
        • Disadvantages
          • Genes could be passed on to wild plants and they could become resistant to the herbicide
          • Long term effects on enviroment is unknown
          • Long term effects on human health unknown
        • Trials = Large scale trials to check for effect on human health
        • How?
          • DNA of soya plant cut open
          • Gene for herbicide resistance put into DNA of soya plant
          • Gene for herbicide resistance cut out of DNA of plant not killed by herbicide

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