Chapter 3
Amino Acids, Peptides and Proteins
1. At very low pH most amino acids is have a _____ charge.
Ans: positive
Link to: 3.1
Difficulty: Easy
2. Disulfide bonds are formed between two ______amino acids.
Ans: cysteine
Link to: 3.1
Difficulty: Easy
3. In the condensation of two amino acids one molecule of ______is lost.
Ans: water
Link to: 3.2
Difficulty: Easy
4. Amino acids linked together in a chain are called a ______.
Ans: polypeptide
Link to: 3.2
Difficulty: Easy
5. Protein in the food we eat is digested by enzymes called ______.
Ans: peptidases
Link to: 3.2
Difficulty: Easy
6. A deficiency in vitamin C causes defects in collagen, which is classified as a _____ protein.
Ans: structural
Link to: 3.3
Difficulty: Easy
7. The protein ______participates in oxygen dispersal in muscle.
Ans: myoglobin
Link to: 3.3
Difficulty: Easy
8. A polypeptide can fold into an individual unit of structure called a ______.
Ans: domain
Link to: 3.3
Difficulty: Easy
9. A protein that contains more than one subunit is called ______.
Ans: oligomeric
Link to: 3.4
Difficulty: Easy
10. A secondary structure which forms a coiled shape with a specific repeating pattern, stabilized by hydrogen bonds, is called a(n)______.
Ans: alpha helix
Link to: 3.4
Difficulty: Medium
11. The sequence of amino acids in a protein, from N to C-terminus, is referred to as the ______structure.
Ans: primary
Link to: 3.4
Difficulty: Easy
12. Related proteins contain large regions of sequence ______.
Ans: homology
Link to: 3.5
Difficulty: Easy
13. The purity and size of a protein can be determined by ______.
Ans: electrophoresis
Link to: 3.5
Difficulty: easy
14. The amino acid which gives the taste of unami is ______.
Ans: glutamic acid
Link to: 3.5
Difficulty: Easy
15. Sickle cell anemia is caused by an amino acid ______.
Ans: substitution (or replacement)
Link to: 3.5
Difficulty: easy
16. The collective group of all the proteins is called the:
a) protosome.
b) proteome.
c) genome.
d) prion.
e) liposome.
Ans: b
Link to: Intro
Difficulty: Easy
17. Amino acids are considered zwitterions because they:
a) exist as dipolar ionic species.
b) were discovered by H. Zwitter.
c) are white solids.
d) are soluble in water.
e) conduct an electric current.
Ans: a
Link to: 3.1
Difficulty: Easy
18. The pK values for amino groups are typically in the pH range:
a) 0-2
b) 4-6
c) 6-8
d) 8-10
e) 4-8
Ans: d
Link to: 3.1
Difficulty: Medium
19. Amino acids contain the following groups linked to a carbon:
a) an amino group and a carboxylate group.
b) an amino group and an R group .
c) a carboxylate group and an R group.
d) an amino group and a carboxylate group and an R group.
e) none of the above
Ans: d
Link to: 3.1
Difficulty: Medium
20. The amino acids with charged side chains include:
a) aspartate, glutamate, lysine and arginine.
b) aspartate, glutamate and glycine.
c) aspartate, lysine and arginine.
d) aspartate, glutamate, lysine, glycine and arginine.
e) none of the above
Ans: a
Link to: 3.1
Difficulty: Medium
21. The net charge of the peptide Arg-Phe-Gly-Lys-Glu at pH 7 is:
a) +2
b) +3
c) -2
d) +1
e) -3
Ans: d
Link to: 3.1
Difficulty: Medium
22. Which of the following is not an amino acid inserted into proteins by a “dedicated” tRNA?
a) selenocysteine
b) proline
c) phosphoserine
d) glycine
e) asparagine
Ans: c
Link to: 3.1
Difficulty: Medium
23. In order to design a drug that could enter a cell, a scientist might consider how it would interact with a ____ protein located on the cellular membrane.
a) defense
b) structural
c) catalytic
d) immune
e) transport
Ans: e
Link to: 3.3
Difficulty: Medium
24. Which of the following characteristics is consistent with the description of a fibrous protein, but not a globular protein?
a) water insoluble
b) dissolved in biological fluids
c) high content of polar amino acids
d) low tensile strength
e) often function as transport proteins
Ans: a
Link to: 3.4
Difficulty: Medium
25. The heme found in myoglobin is a:
a) domain.
b) prosthetic group.
c) zinc finger.
d) peptide.
e) none of the above
Ans: b
Link to: 3.4
Difficulty: Medium
26. Which of the following is not a type of secondary structure found in proteins?
a) sheet
b) helix
c) random coil
d) random turn
e) disulfide bond
Ans: e
Link to: 3.4-3.5
Difficulty: easy
27. If designing a drug that inhibited a large, multisubunit enzyme, it would be important to know how the drug interacted with the:
a) primary structure.
b) mRNA structure.
c) secondary structure.
d) tertiary structure.
e) quaternary structure.
Ans: e
Link to: 3.4
Difficulty: Medium
28. Proteins with charges can be separated by ______chromatography.
a) exclusion
b) size
c) affinity
d) ion exchange
e) gel
Ans: d
Link to 3.5:
Difficulty: Medium
29. Protein sequences can be determined by:
a) amino acid sequencing of the protein.
b) determining the amino acid composition.
c) sequencing the DNA of the protein’s corresponding gene.
d) a and b
e) a and c
Ans: e
Link to: 3.5
Difficulty: Medium
30. Protein sequence data cannot be used to:
a) determine mutations.
b) estimate three-dimensional structure.
c) determine the exact DNA sequence.
d) deduce about biological function.
e) obtain evolutionary data.
Ans: c
Link to: 3.5
Difficulty: Medium
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