Which of the following shows all of the tripeptides that can be formed from one molecule each of alanine (Ala),methionine (Met),and proline (Pro)?
A) AlaMetPro
B) AlaMetPro and AlaProMet
C) AlaMetPro, AlaProMet, ProMetAla, ProAlaMet, MetProAla, MetAlaPro
D) AlaMetPro, AlaProMet, ProAlaMet
E) AlaMetPro, AlaProMet, ProAlaMet, MetProAla

Question

Quizplus · Accepted Answer

To find all possible tripeptides from one molecule each of Ala, Met, and Pro, we need to consider all possible arrangements of these three amino acids. Since order matters, we can use the permutation formula: 
nPr = n! / (n - r)! 
where n is the total number of items (in this case, 3) and r is the number of items we want to arrange in each permutation (in this case, also 3). 
Using this formula, we find that there are 3! = 6 possible permutations or arrangements of Ala, Met, and Pro: 
AlaMetPro, AlaProMet, MetAlaPro, MetProAla, ProAlaMet, ProMetAla. 
Each of these arrangements represents a different tripeptide. Therefore, the correct answer is C, which includes all 6 possible tripeptides.

Which of the Following Shows All of the Tripeptides That