Answer:
A) Species A and E are very closely related more than species A or E are related to species D.
B) Between A and B = 99.1%
Between species A and C =97.5%
Between species B and C = 97.3%
Similarity in amino acids sequence reflects similarity in DNA sequence, therefore they are used to determine how closely species are related.
C) Species A and E are most closely related
D) Since species A and E are most similar in amino acid sequence, it then means that there genetic sequences are most closely related.
Explanation:
A) The amino acid sequences of keratin, in species A and D have a difference of 19 whereas species A and E are different for only one amino acid. Therefore, it means that keratin in species A and D will have significant differences in their structure whereas between species A and E, they would have very similar structures.
Species D and E have a difference of 20 in their amino acids sequences, therefore, the structure of keratin in both species will have significant differences in their structures.
B) Similarity between A and B:
450 - 4 = 446
As a percentage: 446/450 × 100% = 99.1%
Similarity between A and C:
450 - 11 = 439
As a percentage: 439/450 × 100% = 97.5%
Similarity between B and C:
450 -12 = 438
In percentage: 438/450 × 100% = 97.3%
The DNA sequence of species determines their amino acid sequences because information in DNA is transcribed to RNA which are then used to make proteins. Therefore, if a species are very closely related, they are expected to have very similar genetic sequences (or genes) and thus similar proteins too. This similarity in proteins is observed in the similarity between amino acid sequences in their respective proteins.
C). Species A and E are most closely related.
D) Species A and E have only a single difference in their amino acids sequence for Keratin. This is equal to about 99.7% similarity, the highest similarity observed among all the species compared.
