Amino Acids, Peptides & Proteins Questions PDF

1. What is the general structure of a 2-amino acid? * A) R-CH(NH2)-COOH * B) R-CH(NH2)-COOR' * C) R-CO-NH-R' * D) R-CH(OH)-COOH 2. Which two functional groups are present in all 2-amino acids? * A) Amine and ester * B) Amine and carboxylic acid * C) Alcohol and carboxylic acid * D) Amide and carbox...

1. What is the general structure of a 2-amino acid? * A) R-CH(NH2)-COOH * B) R-CH(NH2)-COOR' * C) R-CO-NH-R' * D) R-CH(OH)-COOH 2. Which two functional groups are present in all 2-amino acids? * A) Amine and ester * B) Amine and carboxylic acid * C) Alcohol and carboxylic acid * D) Amide and carboxylic acid 3. What is a zwitterion? * A) A molecule with a positive charge. * B) A molecule with a negative charge. * C) A molecule with both a positive and a negative charge, but no overall charge. * D) A molecule with no charge. 4. In a strongly acidic solution (low pH), what is the predominant form of an amino acid? * A) Cationic * B) Anionic * C) Zwitterionic * D) Uncharged 5. In a strongly alkaline solution (high pH), what is the predominant form of an amino acid? * A) Cationic * B) Anionic * C) Zwitterionic * D) Uncharged 6. What is the bond formed between two amino acids in a peptide? * A) Ester bond * B) Glycosidic bond * C) Peptide bond * D) Hydrogen bond 7. What type of reaction forms a peptide bond? * A) Hydrolysis * B) Condensation * C) Oxidation * D) Reduction 8. What is the product formed when two amino acids react together? * A) A dipeptide * B) A diester * C) A diamine * D) A dicarboxylic acid 9. What is the by-product formed during the formation of a peptide bond? * A) Ammonia * B) Water * C) Carbon dioxide * D) Hydrogen 10. What type of reaction is the breaking of a peptide bond? * A) Condensation * B) Oxidation * C) Reduction * D) Hydrolysis 11. How many different dipeptides can be formed from two different amino acids, A and B? * A) 2 * B) 3 * C) 4 * D) 5 12. What is the primary structure of a protein? * A) The sequence of amino acids. * B) The folding of the polypeptide chain into alpha-helices and beta- pleated sheets. * C) The overall 3D structure of the protein. * D) The interaction of multiple polypeptide chains. 13. What is the secondary structure of a protein? A) The sequence of amino acids. * B) The folding of the polypeptide chain into alpha-helices and beta- pleated sheets. * C) The overall 3D structure of the protein. * D) The interaction of multiple polypeptide chains. 14. What is the tertiary structure of a protein? * A) The sequence of amino acids. * B) The folding of the polypeptide chain into alpha-helices and beta- pleated sheets. * C) The overall 3D structure of the protein. * D) The interaction of multiple polypeptide chains. 15. Which of the following interactions is NOT involved in maintaining the tertiary structure of a protein? * A) Hydrogen bonds * B) Disul de bridges * C) Ionic interactions * D) Peptide Bonds Answers and Explanations: 1. A - R-CH(NH2)-COOH. The amine and carboxylic acid are both attached to the *second* carbon. 2. B - Amine (-NH2) and carboxylic acid (-COOH) 3. C - A zwitterion has both positive and negative charges, but is neutral overall. 4. A - The -NH2 group accepts a proton to become -NH3+. 5. B - The -COOH group loses a proton to become -COO-. 6. C - A peptide bond is a type of amide bond (-CONH-). 7. B 8. A - A dipeptide is formed from two amino acids. 9. B - Water is eliminated in a condensation reaction. 10. D 11. C The possible dipeptides are AA, AB, BA and BB. 12. A - The primary structure is the speci c sequence of amino acids. 13. B 14. C 15. D Peptide bonds are strong covalent bonds and hold the primary structure of the protein together. fi fi Pow