10.3 OTHER BIOCHEMICAL EVIDENCE

proteins

long chains of amino acids linked together in a sequence

how do we use protein sequences to compare species?

• comparing type and sequence of amino acids in similar proteins in different species

• animals of same species= identical amino acid sequences in proteins

• animals of different species= have different amino acids or are arranged in a different order

what does the degree of difference between protein sequences tell us?

gives an estimate on the amount of evolution that has taken place since the 2 species developed from a common ancestor

• longer the period of time= more amino acids that are different

ubiquitous proteins

• one of a group of proteins that appears to be in all species

• these proteins perform very basic, but essential tasks that an organism requires for life

• these proteins are completely independent of an organism’s specific function or environment in which it lives

• these proteins carry out same function no matter where they are found e.g. Cytochrome C

what is bioinformatics?

• uses biochemical analysis to gain information about DNA and proteins and computer software to store and analyse it

• can measure changes in DNA

annotation

identification of genes in a DNA sequence

why are annotations computerised?

most genomes are far too large to be annotated by hand