How many different tripeptides can be made that contain serine,glycine and phenylalanine?
A)1
B)2
C)3
D)6

Question

Quizplus · Accepted Answer

There are three positions for the amino acids in the tripeptide, and each position can be occupied by any of the three given amino acids (serine, glycine, and phenylalanine). Therefore, the total number of possible tripeptides is 3x3x3=27. However, since we are restricted to using serine, glycine, and phenylalanine, we can eliminate all 24 tripeptides that do not contain these amino acids. That leaves us with 3 possible tripeptides, which are: serine-glycine-phenylalanine, glycine-serine-phenylalanine, and phenylalanine-serine-glycine.

How Many Different Tripeptides Can Be Made That Contain Serine,glycine