incorrect multiple choice question?

[lbeste12]

The function of a protein is determined by:
A. The sequence of amino acids
B. The amalgamation of two or more polypeptide chains
C. The tertiary structure of the protein
D. The presence of disulphide bridges

I chose A, but the answers say that it's C, which I believe to be wrong because if you change one amino acid in the sequence then the whole function changes!

Or, I could just be really tired from frantically doing practice exams before my official school practice exam...which is in 1 hour :|

[Charmz]

It is C because the structure is what determines the function. However a is correct it's just that C is more correct
EDIT: Proteins cannot function with out at least a tertiary structure.

[lexitu]

Yeah it's an interesting question. The most correct answer is C. Yeah, the primary structure is important in determining both structure and function, but other things happen to the protein before a final structure manifests such as modification by chaperone proteins. Therefore C is definitely the correct answer.

[Russ]

if you change one amino acid in the sequence then the whole function changes!

As stated above, but this is also not the case.