Paper Chromatography (Upt for each blank /50) R\"group Polarity nonpolar, polar,
ID: 1032908 • Letter: P
Question
Paper Chromatography (Upt for each blank /50) R"group Polarity nonpolar, polar, or polar with H- Size of "R" Group small, medium, spray large Distance Distance Traveled by Traveled by Rf Amino Acid Mobile Phase after Amino Acicd .5 om 3.1 2.5 Serme Cm SL 521 Leucime A.R D2y Unknowrn Unknown codeDY Unknown identityusine (10 pts- No Unknown code Opts) In complete sentences on the back of this page or on a separate piece of paper answer the following questions. (5 pts each) 1. Choose any two known amino acids with similar Rr and based on the size and polarity of their side chains, give an explanation for why their retention factors are similar. 2. Choose any two known amino acids with very different Rr values and based on the size and polarity of their side chains, give an explanation for why their retention factors are dissimilar. 3. Explain why lysine's Rr is lower than that of leucine, even though they both have the same number of carbon atoms in their side chains. 4 When you supplied the beaker with solvent, you were cautioned that the solvent level should be below the samples spotted on the chromatography paper. Why? 34Explanation / Answer
1. Choose any 2 known amino acids with similar Rf and based on the size and polarity of their side chains, give an expalanation for why their retention factors are similar.
Tyrosine and tryptophan have similar Rfs. Tyrosine has an Rf of 2.5 and tryptophan has an Rf of 2.8. The base unit has an amino and a caroxyl group which is the simliarity in bot of these structures. The aromartic grops attahced are the ones that bring the structural differences. The substituent on tyrosine is the 4-Hydroxy phenyl group and in case of trptophan it is the indole ring. Both these aromatic groups are of similar polarity, one has an NH attached to a benzene ring with a cyclic strcuture and the other has a OH group attached to benzene. NH and OH are both, of similar polarity and hence are equally retained by the polar silica on the TLC. So they both tend to move similar distance on the TLC.
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