Protein structure— formative assessment

1. Protein structure—formative assessment AP Biology 10/7/2013

2. Level 2.0

3. 1. What is the name for the variable region of the 20 amino acids? • Carboxyl group • Amino group • R group • Alpha Carbon

4. 2. What functional group must be present in the R group of an acidic (-) amino acid? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

5. 3. What functional group must be present in the R group of a basic (+) amino acid? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

6. 4. What functional group is most often present in a neutral, yet hydrophilic, amino acid’s R group? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • sulfahydryl

7. 5. What functional group in cysteine and methionine allows them to form strong covalent bonds that stabilize a protein’s tertiary structure? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

8. 6. Which arrow points to a peptide bond? • a • b • c • d a b c d a

9. Level 3.0

10. 7. How do alpha helices and Beta pleated sheets compare? • They are both forms of protein secondary structure • They are both formed due to formation of H bonds between N-H & C=O groups along the backbone of polypeptide chain • The beta sheets are more rigid & strong because they form more abundant H bonds • All of the above

11. 8. R group interactions control which levels of protein folding? • Primary structure & secondary structure • Secondary structure only • Tertiary & quartenary structure • Tertiary structure only • Quartenary structure only

12. 9. Which amino acids tend to cluster in the center of an aqueous protein, but to be located on the outer edges of proteins located within a cell membrane’s lipid bilayer? • Acidic amino acids • Basic amino acids • Disulfide bridge forming cysteines & methionines • Polar, hydrophilic amino acids • Nonpolar, hydrophobic amino acids

13. If your answers were correct for 8 or 9 questions, then you should work independently on Stanford notes for Chapter 6. This power point will be online for your use in studying. If you answered 7 or fewer questions correctly, you should review the next explanation slides.

14. 1. What is the name for the variable region of the 20 amino acids? • Carboxyl group • Amino group • R group • Alpha Carbon

15. Every amino acid contains a central (α) C, surrounded by a H, an R group (variable group), an amino group, and a carboxyl group. The amino group acts as a base, accepting a protons, whereas the carboxyl group acts as an acid, donating a proton.

16. Every amino acid contains a central (α) C, surrounded by a H, an R group (variable group), an amino group, and a carboxyl group. The amino group acts as a base, accepting a protons, whereas the carboxyl group acts as an acid, donating a proton.

18. 2. What functional group must be present in the R group of an acidic (-) amino acid? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

19. About 1 x 10-7 Moles water /L dissociates to produce H+ ions and OH- ions. The ratio of the two ions is 1.0, and the pH is 7—neutral. When substances known as acids are dissolved in water, then they dissociate to produce H+ions, making the H+:OH- ratio higher than 1.0. Acids are proton donors when dissolved in aqueous solution. Carboxyl groups behave asacids because they dissociateto release H+ions. The amino acidsaspartic acid & glutamic acids have a carboxyl group in their group, so they are acidic aminoacids.

21. 3. What functional group must be present in the R group of a basic (+) amino acid? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

22. Bases either release OH- OR accept H+ ions when dissolved in aqueous solution. In both cases, bases reduce the H+: OH- ratio to less than 1.0 The amino group in an amino acid’s R group acts as a base, accepting a proton. The amino acids arginine and lysine act as bases.

24. 4. What functional group is most often present in a neutral, yet hydrophilic, amino acid’s R group? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • sulfahydryl

26. 5. What functional group in cysteine and methionine allows them to form strong covalent bonds that stabilize a protein’s tertiary structure? • Carboxyl group • Amino group • Hydroxyl group • Carbonyl group • Sulfahydryl group

28. 6. Which arrow points to a peptide bond? • a • b • c • d a b c d a

29. Level 3.0

30. 7. How do alpha helices and Beta pleated sheets compare? • They are both forms of protein secondary structure • They are both formed due to formation of H bonds between N-H & C=O groups along the backbone of polypeptide chain • The beta sheets are more rigid & strong because they form more abundant H bonds • All of the above

31. Protein structure

32. 8. R group interactions control which levels of protein folding? • Primary structure & secondary structure • Secondary structure only • Tertiary & quartenary structure • Tertiary structure only • Quartenary structure only

33. R group interactions control tertiary & Quarternary structure

34. 9. Which amino acids tend to cluster in the center of an aqueous protein, but to be located on the outer edges of proteins located within a cell membrane’s lipid bilayer? • Acidic amino acids • Basic amino acids • Disulfide bridge forming cysteines & methionines • Polar, hydrophilic amino acids • Nonpolar, hydrophobic amino acids