Two proteins are known to have the same sequence at the amino terminus of the protein,most logical conclusion

1. must be coded for by the same DNA sequence.
2. must have been obtained from the same biological source.
3. All of these answers.
4. may have a similar function.
5. will have the same sequence at the carboxy terminus.

4. may have a similar function.


Of the available choices, it is the best one, because:

1) it qualifies itself ("may" vs "must be", "must have", and "will have")
2) If the sequence at the amino terminus is the same, they may both be targeted to the same or similar location, and therefore may perform similar functions.

Extremely bad question. Your teacher seriously sucks.

Why this is bad: No specification of how long the polypeptides are, nor how long the matching amino terminus sequence is.

Say for example one polypeptide is 100 peptides long, the other is 200 long, and the matching sequence is 2 peptides long. These proteins aren't related at all.

Kick this question back to your teacher for a fixup.