One of the peptides that can be recovered after gluten digestion is 33 residues long; 13 of the 33 residues are proline. how many times would you expect proline to appear in this peptide if it were made up of a completely random assortment of the 20 most common amino acids?

It's expected that proline would appear between once or twice.

Step-by-step explanation:

If it were made up of a random assortment of amino acids, each amino acid can have:

chance of being in any particular place in the sequence.

Therefore, Proline has a chance of being in each place.

We've got 33 places,

So if we can multiply the places we've got times the chances and we get:

or 1.65

Therefore it's expected that proline would appear between once or twice.