A biologist determined the amounts of several amino acids in two separate samples of pure protein. His data showed that Protein A contained 7% leucine, 12% alanine, 4% histidine, 2% cysteine, and 5% glycine. Interestingly, Protein B had the same percentages of the same amino acids. He concluded from this data that Proteins A and B are the same protein. Based on this information and his conclusion, determine which of the following is the correct statement regarding his findings:
A) He is correct; the proteins have the same percentages of each amino acid, so they are identical protein molecules.
B) He is incorrect; there is no information about the amino acids sequence (which dictates the overall structure of a protein), so the two proteins could be very different in shape.
C) He is correct; although there is no information on the amino acid sequence in each protein, the order of the amino acids is irrelevant. It's only the total number of each molecule that is important to structure.
D) He is incorrect; he hasn't accounted at all for the effects of pH on the composition of the protein and its effects on the individual amino acids.
E) He is partly correct; the percentage of the listed amino acids is the same in each protein, but Protein A is hydrophobic and Protein B is hydrophilic.

Question

A biologist determined the amounts of several amino acids in two separate samples of pure protein. His data showed that Protein A contained 7% leucine, 12% alanine, 4% histidine, 2% cysteine, and 5% glycine. Interestingly, Protein B had the same percentages of the same amino acids. He concluded from this data that Proteins A and B are the same protein. Based on this information and his conclusion, determine which of the following is the correct statement regarding his findings:
A) He is correct; the proteins have the same percentages of each amino acid, so they are identical protein molecules.
B) He is incorrect;  there is no information about the amino acids sequence (which dictates the overall structure of a protein), so the two proteins could be very different in shape.
C) He is correct; although there is no information on the amino acid sequence in each protein, the order of the amino acids is irrelevant. It's only the total number of each molecule that is important to structure.
D) He is incorrect; he hasn't accounted at all for the effects of pH on the composition of the protein and its effects on the individual amino acids.
E) He is partly correct; the percentage of the listed amino acids is the same in each protein, but Protein A is hydrophobic and Protein B is hydrophilic.

Quizplus · Accepted Answer

The biologist's conclusion is incorrect because the percentages of amino acids alone do not provide enough information to determine if two proteins are identical in shape and function. The sequence and arrangement of the amino acids are crucial in determining the overall structure and function of a protein. Therefore, it is possible that Proteins A and B have different amino acid sequences, resulting in proteins with different structures and functions.

A Biologist Determined the Amounts of Several Amino Acids in Two