Which of the following best shows how primary structure relates to protein function?

A. High temperatures cause proteins to denature.



B. Changing one amino acid in the protein hemoglobin causes sickle-cell anemia.



C. Proteins are sensitive to changes in pH.



D. The shape and chemistry of an enzyme's active site determine its functionWhich of the following best shows how primary structure relates to protein function?
B



Changing one amino acid in hemoglobin results in a different protein structure under oxygen stress conditions which results in a deformed red blood cell (sickle-cell anemia).Which of the following best shows how primary structure relates to protein function?
The answer is B.

Primary structure is the specific amino acid sequence coded by DNA which makes up a protein. It is not how it folds or the shape of the structure.



In sickle-cell anemia the normal sixth amino acid (Glu) is replaced by Val, which in turn changes the entire shape of the cell (hence the sickle shape). So therefore the shape change is due to an error in primary structure (the coded amino acid sequence).





Explained wrong answers:





It is not A because, while high temperatures DO cause the denaturization of proteins, this does not effect primary structure, it affects the shape. When it denatures the bonds (such as the weak Hydrogen bounds of secondary structure) the protein looses its specific shape and can no longer function, but if the conditions are returned to normal it will return to its specific shape because the primary structure was not effected. And primary structure determines the bonds since it determines the amino acid sequence.



C is incorrect because pH changes, like temperature changes, can denature but only effect secondary, tertiary, and quaternary structure.



D is incorrect because it is once again referring to shape. While the statement is true, it does not answer the question.









Hope this helped / is very clear.
b;