Question 1

The amino acid with the most hydrophobic side chain is

Accepted Answer

A)  asparagine. 
B)  aspartate. 
C)  valine. 
D)  threonine. 
A)  asparagine. 
B)  aspartate. 
C)  valine. 
D)  threonine.

Question 2

A __________ mutation in a gene results in the least amount of damage to the resulting protein.

Accepted Answer

A)  missense 
B)  nonsense 
C)  frameshift 
D)  silent 
A)  missense 
B)  nonsense 
C)  frameshift 
D)  silent

Question 3

The common protein fold shown below is the __________ fold.

Accepted Answer

A)  Greek key 
B)  Rossman 
C)  FERM domain 
D)    /  Barrel 
A)  Greek key 
B)  Rossman 
C)  FERM domain 
D)    /  Barrel

Question 4

Which of the following statements is true about   -helices?

Accepted Answer

A)  The center of the helix is an open channel. 
B)  There are about seven amino acids per helical turn. 
C)  The amide backbone dipoles line up in one direction. 
D)  The helical backbone structure is stabilized by ionic interactions. 
A)  The center of the helix is an open channel. 
B)  There are about seven amino acids per helical turn. 
C)  The amide backbone dipoles line up in one direction. 
D)  The helical backbone structure is stabilized by ionic interactions.

Question 5

The amino acid with the neutral side chain at neutral pH is

Accepted Answer

A)  asparagine. 
B)  aspartate. 
C)  arginine. 
D)  glutamate. 
A)  asparagine. 
B)  aspartate. 
C)  arginine. 
D)  glutamate.

Question 6

Cells deal with misfolded proteins by

Accepted Answer

A)  storing them for later energy use. 
B)  collecting and excreting them from the cell. 
C)  aggregating them to maintain the cell's structural integrity. 
D)  degrading them to individual amino acids. 
A)  storing them for later energy use. 
B)  collecting and excreting them from the cell. 
C)  aggregating them to maintain the cell's structural integrity. 
D)  degrading them to individual amino acids.

Question 7

Which one of the following statements comparing alpha keratin and silk fibroin is true?

Accepted Answer

A)  Both have covalently cross-linked strands. 
B)  Both are primarily  -helical in character. 
C)  Both fibers are intracellularly located. 
D)  Both fibers are heavily stabilized by hydrogen bonds. 
A)  Both have covalently cross-linked strands. 
B)  Both are primarily  -helical in character. 
C)  Both fibers are intracellularly located. 
D)  Both fibers are heavily stabilized by hydrogen bonds.

Question 8

How many   -turns or  -loops are required to construct a  -sheet composed of four antiparallel strands?

Accepted Answer

A)  0 
B)  3 
C)  4 
D)  5 
A)  0 
B)  3 
C)  4 
D)  5

Question 9

All of the following are types of protein secondary structure EXCEPT

Accepted Answer

A)    -sheets. 
B)    -helixes. 
C)    -helixes. 
D)    -turns. 
A)    -sheets. 
B)    -helixes. 
C)    -helixes. 
D)    -turns.

Question 10

The proteins collagen,silk fibroin,and hair keratin have all of the following in common,EXCEPT that they

Accepted Answer

A)  are fibrous proteins. 
B)  are composed of repeating amino acid sequences. 
C)  are composed of  -helical structures. 
D)  play important structural roles in biology. 
A)  are fibrous proteins. 
B)  are composed of repeating amino acid sequences. 
C)  are composed of  -helical structures. 
D)  play important structural roles in biology.

Question 11

Draw the structure of the amino acid cysteine showing the predominant form found at pH = 12.0 (assume   NH3+ pKa 9.0; Cys pKR 8.0;   COOH pKa 2.0).

Accepted Answer

Question 12

Which of the following statements about Ramachandran plots is true?

Accepted Answer

A)  They are good predictors of protein tertiary structure. 
B)  They are needed to determine the secondary structure of a protein. 
C)  They show equal distributions of  And  Angles for  -helical and  -sheet containing proteins. 
D)  They show that  -sheets and  -helices occupy different  And  Angles. 
A)  They are good predictors of protein tertiary structure. 
B)  They are needed to determine the secondary structure of a protein. 
C)  They show equal distributions of  And  Angles for  -helical and  -sheet containing proteins. 
D)  They show that  -sheets and  -helices occupy different  And  Angles.

Question 13

The chirality of naturally occurring amino acids in proteins is

Accepted Answer

A)  R. 
B)  L. 
C)  D. 
D)  the same as glyceraldehyde. 
A)  R. 
B)  L. 
C)  D. 
D)  the same as glyceraldehyde.

Question 14

Christian Anfinsen showed in a famous experiment that it is possible to unfold a protein and refold it to obtain a functional protein.Which two reagents were used in this experiment to unfold the protein?

Accepted Answer

A)  detergent and salt 
B)  urea and  -mercaptoethanol 
C)  acid and base 
D)  ethanol and  -mercaptoethanol 
A)  detergent and salt 
B)  urea and  -mercaptoethanol 
C)  acid and base 
D)  ethanol and  -mercaptoethanol

Question 15

If the titration curve shown below is for the amino acid glycine,at which point in the curve is the pI?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 16

Which statement about amino acids is true?

Accepted Answer

A)  Most common natural amino acids in proteins are L-amino acids. 
B)  All naturally occurring amino acids in proteins are chiral. 
C)  Most naturally occurring amino acids in proteins are D-amino acids. 
D)  Naturally occurring amino acids in proteins occur as a mixture of enantiomers. 
A)  Most common natural amino acids in proteins are L-amino acids. 
B)  All naturally occurring amino acids in proteins are chiral. 
C)  Most naturally occurring amino acids in proteins are D-amino acids. 
D)  Naturally occurring amino acids in proteins occur as a mixture of enantiomers.

Question 17

The points in the Ramachandran plot are derived by

Accepted Answer

A)  counting the number of amino acids and placing points in allowed regions. 
B)  measuring the  And  Angles in an experimentally determined protein crystal structure. 
C)  placing each amino acid in regions commonly occupied by that amino acid. 
D)  experimentally measuring the optical rotation of polarized light. 
A)  counting the number of amino acids and placing points in allowed regions. 
B)  measuring the  And  Angles in an experimentally determined protein crystal structure. 
C)  placing each amino acid in regions commonly occupied by that amino acid. 
D)  experimentally measuring the optical rotation of polarized light.

Question 18

Would a nonsense mutation in a gene encoding a protein be expected to result in a gain-of-function or a loss-of-function protein folding disease?

Accepted Answer

It might result in either disease or nei

Question 19

Draw the structure of the amino acid glutamate showing the predominant form found at pH 7.0 (assume   NH3+ pKa 9.0; Glu pKR 4.0;   COOH pKa 2.0).

Accepted Answer

Question 20

Using the pKas shown,what is the isoelectric point of the amino acid tyrosine?

Accepted Answer

A)  <1.0 
B)  5.5 
C)  7.0 
D)  9.75 
A)  <1.0 
B)  5.5 
C)  7.0 
D)  9.75

Exam 4: Protein Structure

The amino acid with the most hydrophobic side chain is

A __________ mutation in a gene results in the least amount of damage to the resulting protein.

The common protein fold shown below is the __________ fold.

Which of the following statements is true about -helices?

The amino acid with the neutral side chain at neutral pH is

Cells deal with misfolded proteins by

Which one of the following statements comparing alpha keratin and silk fibroin is true?

How many -turns or -loops are required to construct a -sheet composed of four antiparallel strands?

All of the following are types of protein secondary structure EXCEPT

The proteins collagen,silk fibroin,and hair keratin have all of the following in common,EXCEPT that they

Draw the structure of the amino acid cysteine showing the predominant form found at pH = 12.0 (assume NH3+ pKa 9.0; Cys pKR 8.0; COOH pKa 2.0).

Which of the following statements about Ramachandran plots is true?

The chirality of naturally occurring amino acids in proteins is

Christian Anfinsen showed in a famous experiment that it is possible to unfold a protein and refold it to obtain a functional protein.Which two reagents were used in this experiment to unfold the protein?

If the titration curve shown below is for the amino acid glycine,at which point in the curve is the pI?

Which statement about amino acids is true?

The points in the Ramachandran plot are derived by

Would a nonsense mutation in a gene encoding a protein be expected to result in a gain-of-function or a loss-of-function protein folding disease?

Draw the structure of the amino acid glutamate showing the predominant form found at pH 7.0 (assume NH3+ pKa 9.0; Glu pKR 4.0; COOH pKa 2.0).

Using the pKas shown,what is the isoelectric point of the amino acid tyrosine?

Principles of Biochemistry

Physical Biochemistry: Energy Conversion,water,and Membranes

Nucleic Acid Structure and Function

Methods in Protein Biochemistry

Protein Function

Enzyme Mechanisms

Cell Signaling Systems

Glycolysis: a Paradigm of Metabolic Regulation

The Citrate Cycle

Oxidative Phosphorylation

Photosynthesis

Carbohydrate Structure and Function

Carbohydrate Metabolism

Lipid Structure and Function

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Metabolic Integration

Dna Replication, repair, and Recombination

Rna Synthesis, processing, and Gene Silencing

Protein Synthesis, posttranslational Modification, and Transport

Gene Regulation

Filters

Draw the structure of the amino acid cysteine showing the predominant form found at pH = 12.0 (assume NH₃₊ pKa 9.0; Cys pK_R 8.0; COOH pKa 2.0).

Draw the structure of the amino acid glutamate showing the predominant form found at pH 7.0 (assume NH₃₊ pKa 9.0; Glu pK_R 4.0; COOH pKa 2.0).