Chemical Structure of Amino Acids

15 Points Per Correct Answer - No time limit  

1. The simplest of all amino acids, which amino acid is represented by this R group (A=amino acid backbone): A-H ? Alanine Proline Methionine Glycine

2. One of two sulfur-containing amino acids, which amino acid has the following R group (A=amino acid backbone): A-CH2-SH ? Histidine Cysteine Tryptophan Serine

3. Which amino acid's R group is this (A=amino acid backbone, neg=negative charge): A-CH2-CH2-C(=O)-O(neg) ? Answer: (Two Words, one of two acidic amino acids)

4. Name the amino acid, one of three alcohol (-OH) containing amino acids, that this R group is part of (A=amino acid backbone): A-CH(CH3)-OH Proline Threonine Isoleucine Valine

5. Which unusual amino acid does this R group belong to (pos=positive charge): A closed ring structure forming from alpha C-CH2-CH2-CH2-H2N(pos)-alpha C. [NB: only one alpha C is present, this closes the ring. Alpha C and H2N(pos) are part of amino acid backbone.] Leucine Phenylalanine Proline Arginine

6. This structure represents the R group of which amino acid, which is known for its role in mutations causing sickle-cell anemia [A=amino acid backbone]: A-CH(CH3)-CH3 ? Leucine Alanine Valine Threonine

7. Which amino acid, first obtained from silk, has this R group [A=amino acid backbone]: A-CH2-OH ? Proline Isoleucine Serine Arginine

8. Which amino acid, the second most commonly integrated into proteins, has this R group [A=amino acid backbone]: A-CH3 ? Alanine Threonine Glycine Histidine

9. Which aromatic amino acid is represented by this R group (A=amino acid backbone): A-CH2-pentagonal ring containing an NH group and double bond-hexagonal phenyl group ? (Or A-CH2-indole ring) [Sorry for the poor representation!] Isoleucine Tryptophan Aspartic acid Alanine

10. Which amino acid has this R group and plays an important role in secondary structures of proteins [A=amino acid backbone]: A-CH2-C(=O)-NH2 ? Aspartic acid Asparagine Leucine Isoleucine

11. Which aliphatic amino acid does this represent [A=amino acid backbone]: A-CH2-CH(CH3)-CH3 ? Leucine Valine Isoleucine Alanine

12. Which amino acid, one of three basic amino acids, does this R group represent [A=amino acid backbone, (pos)=positive charge]: A-CH2-CH2-CH2-CH2-NH3(pos) ? Valine Methionine Lysine Tyrosine

13. Which amino acid is represented here by this R group [A=amino acid backbone]: A-CH(CH3)-CH2-CH3 ? Answer: (One word, It is an ISOmer of another amino acid)

14. Which amino acid has the following R group (A=amino acid backbone): A-CH2-Ph [Hint: Ph is C6H5, a phenyl group.] Answer: (One Word)

15. Which amino acid is represented by the following R group and is abundant in blood in its free form: [A=amino acid backbone] : A-CH2-CH2-C(=O)-NH2 ? Proline Serine Glutamine Tryptophan

16. Which amino acid is represented by this R group and whose charge varies according to environmental pH [A=amino acid backbone, (pos)=positive charge]: A-CH2-(ring form at yC=CH-NH-CH=NH(pos)-yC) ? [NB: yC = gamma carbon. There is only one gamma carbon; the ring begins and ends at this same atom.] Methionine Histidine Aspartic acid Cysteine

17. Which amino acid is represented by this R group, shown here in its carboxylated form [A=amino acid backbone, (neg)=negative charge]: A-CH2-C(=O)-O(neg) ? Leucine Tryptophan Serine Aspartic acid

18. Which amino acid's R group is this, which is integrated first into every polypeptide chain [A=amino acid backbone]: A-CH2-CH2-S-CH3 ? Answer: (One Word, one of two sulfur-containing amino acids)

19. Which amino acid, discovered from a cheese protein, contains this R group [A=amino acid backbone]: A-CH2-Ph-OH ? [Ph - phenyl group.] Answer: (One Word, One letter code is Y)

20. Which amino acid is represented by this R group and is unusual regarding essentiality [A=amino acid backbone, [pos]=positive charge]: A-CH2-CH2-CH2-NH-C(=NH2[pos])-NH2 ? Threonine Lysine Valine Arginine