The molecule above is a short polypeptide.

In the text box below, answer the following questions:

Q1. What element(s) is present in the polypeptide but not always represented
by a letter in the model? How many are there?

Q2. How many amino acids are in the polypeptide chain?

Q3. Before looking at an amino acid structure table, determine how many non-
polar R-groups are present.

Q4. List the single-letter code of the R-groups from the N-terminus to the C-
terminus. (For this one, you should refer to an amino acid structure table- for
example, like this E.)