classification using DNA Flashcards
how can biochemistry aid classification?
changes in evolutionary relationships must have bee mirrored by changes in proteins and therefore DNA. DNA sequencing and immunological analysis can be used to determine how closely related organisms are
describe in terms of bases sequences, how we can tell the difference between species
the differences are caused by mutations in the sequence of bases therefore the fewer base changes, the closer the species are in evolutionary terms
why might the amino acid sequence be the same but the DNA sequence be different in 2 species?
the genetic code could be degenerate therefore more than one codon could code for the the same amino acid
what is cytochrome C?
a protein
why is cytochrome C used for comparison of species?
it can be found in many species, and in all eukaryotic organisms
how can scientists use cytochrome C to compare species?
the more similar the amino acid sequence of cytochrome C in 2 different species, the more closely related they are
how are antibodies used to compare species?
because similar proteins will bind to the same antibodies. The antibodies of one species will respond to the antigens found on proteins such as albumin of another species
explain how immunological comparison is carried out
- Rabbit is injected with human serum which contains pure human albumin
- the rabbit produces antibodies against the human albumin (anti-human albumin antibodies)
- The antihuman antibodies are extracted and purified and are added to the serum of other species
- The more similar the blood to human blood, the greater the reaction.
- The human albumin and human antigens form a precipitate with anti human albumin antibodies and more precipitate forms
what is the result when there’s a greater number of similar antigens?
more precipitate is formed and the more closely the species are related.
what is the result when there’s fewer number of similar antigens?
the less precipitate is formed and the more distantly the species are related
