Which of the Following Is Considered As a Noncovalent Bond

Chem 361

Quiz1 (each question is worth 5 points)

Name:

Date: Sep 29, 2011

Which of the following is considered as a noncovalent bond?

A) / electrostatic interactions / D) / All of the above.
B) / hydrogen bonds / E) / None of the above.
C) / van der Waals interactions
2. / What pairs of atoms in bases are involved in hydrogen bonds?
A) / N—H and O—H / D) / All of the above.
B) / N—H and S—H / E) / None of the above.
C) / O—H and P—O
3. / What two properties of water are important for biological interactions?
A) / the polarity of water / D) / a and c
B) / the density of water / E) / b and c
C) / the cohesive properties of water
4. / List atoms commonly found in biological molecules that are often hydrogen-bond acceptors.
A) carbon B) oxygen C) nitrogen D) b and c E) All of the above.
5. / What happens to nonpolar molecules in water?
A) / They dissolve independently. / D) / All of the above.
B) / They aggregate together. / E) / None of the above.
C) / They precipitate.
6. / What is the [A-]/[HA] ratio when the weak acid is in a solution one pH unit above its pKa?
A) / 1 : 1 / D) / 2 : 1
B) / 1 : 10 / E) / None of the above.
C) / 10 : 1
7. / Stereochemistry can be easily depicted in a simple form using
A) / Ball-and-stick models. / D) / Fisher projections.
B) / ribbon diagrams. / E) / None of the above.
C) / Space-filling models.
8. / Which of the following is the Henderson-Hasselbach equation?
A) / / D) /
B) / / E) / None of the above.
C) /
9. / What determines a protein’s function?
A) / structure / D) / None of the above.
B) / gene sequence / E) / All of the above.
C) / N-terminal amino acids
10. / Key properties of proteins include
A) / a wide range of functional groups.
B) / an ability to possess either rigid or flexible structures as dictated by functional requirements.
C) / the ability to interact with other proteins.
D) / a and b.
E) / All of the above.
11. / At a pH of 1, what charged group(s) are present in glycine?
A) -NH3+ B) -COO- C) -NH2+ D) a and b E) a, b, and c
12. / Which amino acids contain reactive aliphatic hydroxyl groups?
A) / serine and methionine / D) / cysteine and methionine
B) / serine and threonine / E) / cysteine and threonine
C) / methionine and threonine
13. / Name three amino acids that are positively charged at a neutral pH.
A) / lys, arg, and his / D) / lys, arg, and pro
B) / his, arg, and cys / E) / arg, glu, and his
C) / cys, arg, and met
14. / In the following peptide, which amino acid is the N-terminus?
Phe-Ala-Gly-Arg
A) Ala B) Phe C) Phe and Arg D) Arg E) None of the above.
15. / Which of the following affect the sedimentation of a particle?
A) / mass / D) / All of the above.
B) / shape / E) / a and b
C) / the density of the solution
16. / Cyanogen bromide cleaves the peptide bond at
A) / the carboxyl side of Arg and Lys residues.
B) / the carboxyl side of Met residues.
C) / the amino terminus.
D) / None of the above.
E) / All of the above.
17. / Trypsin cleaves the peptide bond at
A) / the carboxyl side of Arg and Lys residues.
B) / the carboxyl side of Met residues.
C) / the amino terminus.
D) / None of the above.
E) / All of the above.
18. / Which of the following techniques can be used to determine the site of a disulfide bond?
A) / Edman degradation / D) / MALDI-TOF
B) / affinity chromatography / E) / SDS-PAGE
C) / diagonal electrophoresis

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