Problem 25
RECALL How do the resonance structures of the peptide group contribute to the planar arrangement of this group of atoms?
Problem 28
REFLECT AND APPLY Consider the peptides Ser - Glu-GlyHis-Ala and Gly-His-Ala- Glu-Ser. How do these two peptides differ?
Problem 30
REFLECT AND APPLY What are the sequences of all the possible tripeptides that contain the amino acids aspartic acid, leucine, and phenylalanine? Use the three-letter abbreviations to express your answer.
Problem 32
REFLECT AND APPLY Most proteins contain more than 100 amino acid residues. If you decided to synthesize a " 100 -mer," with 20 different amino acids available for each position, how many different molecules could you make?
Problem 38
REFLECT AND APPLY Suggest a reason why the amino acids thyroxine and hydroxyproline are produced by posttranslational modification of the amino acids tyrosine and proline, respectively.
Problem 41
REFLECT AND APPLY Suggest a reason why biosynthesis of amino acids and of proteins would eventually cease in an organism with carbohydrates as its only food source.
Problem 43
REFLECT AND APPLY Suggest a reason (or reasons) why amino acids polymerize to form proteins that have comparatively few covalent crosslinks in the polypeptide chain.
Problem 46
REFLECT AND APPLY Speculate on the properties of proteins that would be formed if amino acids were not chiral.
Problem 48
RECALL How do the peptide hormones oxytocin and vasopressin differ in function?
Problem 50
RECALL Is it possible to form cyclic peptides without bonds between side chains of the component amino acids?
