If three amino acids viz., glycine, alanine and phenylalanine react together, how many possible tripeptides can be formed? Write down the structures and names of each one. Also write their names using three and one letter abbreviations for each amino acid.

Write down the structural formula of the tripeptide formed by alanine, glycine and serine joined together in that order.

How many different tripeptides can be obtained from alanine, glycine and phenylalanine, each tripeptide containing all the three amino acids?

Write the name and structural formula of one functional isomer of acetic acid.

In how many ways three different rings can be worn in four fingers with at most one in each finger?

How many words of 4 different letters can be formed out 7 capital letters 3 vowels and 5 consonants if each word starts with a capital letter and contains at least one vowel.

How many tripeptides can be prepared by linking the amino acids glycine, alanine and phenyl alanine?

(a) Let the letters A and B represent two different amino acids. Write down the sequences of all the possible tripeptides that could be made with just these two amino acids. (b) What is the formula for calculating the number of different tripeptides that can be formed from two different amino acids ?