Dna And Amino Acid Comparisons - Center Grove Schools (Page 2 of 3) in pdf

Questions:

1. Identify in the chart below how many total differences of amino acids each organism had when 

compared to the human amino acid sequence. 

Table B

Organism 

# of  differences from human 

Chimpanzee 

Gorilla 

Rhesus monkey 

Horse 

Kangaroo 

2. How many columns from Table A were the amino acids that same for each organism? 

3. Based on the information in Table B above, which organism is the most closely related to humans? 

Explain how you know this. 

4. Based on the information in Table B above, which organism is the least closely related to humans? 

Explain how you know this. 

5. There is a difference of only one amino acid in one chain of hemoglobin between humans and 

gorillas. What might have caused this difference? 

6. If the amino acid sequences in the proteins of two organisms are similar, why will their DNA also 

be similar? (NOTE: What is the relationship between amino acid sequences and DNA?) 

Many biologists believe that the number of differences between the amino acid sequences (proteins) 

of different species indicate how long ago the species diverged from a common ancestor. 

Molecular Clock 

Geologic Time Scale (million years ago) 

450         

350 

270 

  _______________________________________________ 

Hemoglobin Amino Acid Differences 

7. Why do these biologists believe that humans and gorillas diverged from a common ancestor only a 

few million years ago? 

8. There are 79 differences in the amino acid sequence of hemoglobin when you compare humans to 

sharks. How long ago do you think humans and sharks diverged from a common ancestor? 

Dna And Amino Acid Comparisons - Center Grove Schools Page 2