3.2 Chromosomes

3.2 Chromosomes

Nature of Science
1. Autoradiography was used to establish the length of DNA molecules in chromosomes
  1. Cairns' technique
    1. Comparison of genome size
      1. T2 phage
      2. Escherichia coli
      3. Drosophila melanogaster
      4. Homo sapiens
      5. Paris japonica
    2. Aim 6
      1. Staining root tips
    3. Aim 7
      1. Use of databases to identify gene loci and protein products of genes
The number of chromosomes is a characteristic feature of members of a species
1. Prokaryotes
  1. Naked Circular DNA
  2. Plasmid
2. Eukaryotes
  1. Linear DNA with histone proteins
    1. Nucleus
      1. Diploid (2n)
        Have pairs of homologous chromosomes
        Homologous chromosomes carry the same sequence of genes but no necessarily the same alleles of those genes
        Comparison of 2n chromosome numbers
        Pan troglodytes
        Oryza sativa
        Parascaris equorum
        Homo sapiens
        Canis familiaris
      2. Haploid (n)
        One chromosome of each pair
Karyogram vs Karyotype
1. A karyogram shows the chromosomes of an organism in homologous pairs of decreasing length
  1. Sex chromosomes vs Autosomal chromosomes
  2. Deduce sex and diagnose Down syndrome
International-mindedness
1. Sequencing of the rice genome involved cooperation between biologists in 10 countries

Resource summary

	Created by Steve Harton over 10 years ago