Question 1

Which of the following statements about   -sheet structures is true?

Accepted Answer

A)  The individual strands of all  -sheet structures are connected by turns, helices, or loops. 
B)  All amino acid side chains in antiparallel and parallel  -sheet structures point to one side of the sheet. 
C)  Parallel  -sheet structures have backbone amides that directly hydrogen bond between strands, whereas antiparallel  -sheets have hydrogen bonds that are offset. 
D)  All  -sheet structures form a spiraling backbone chain. 
A)  The individual strands of all  -sheet structures are connected by turns, helices, or loops. 
B)  All amino acid side chains in antiparallel and parallel  -sheet structures point to one side of the sheet. 
C)  Parallel  -sheet structures have backbone amides that directly hydrogen bond between strands, whereas antiparallel  -sheets have hydrogen bonds that are offset. 
D)  All  -sheet structures form a spiraling backbone chain.

Question 2

Which of the following statements about the clamp-type chaperone protein Hsp70 is correct?

Accepted Answer

A)  Hsp70 uses ATP binding and hydrolysis energy to assist in the folding of a protein. 
B)  Hsp70 is a multi-subunit protein shaped like a large barrel, inside of which the folding protein is protected. 
C)  Hsp70 is most active during cell division phases. 
D)  Hsp70 assists in protein unfolding by hydrolyzing and remaking the protein peptide bonds. 
A)  Hsp70 uses ATP binding and hydrolysis energy to assist in the folding of a protein. 
B)  Hsp70 is a multi-subunit protein shaped like a large barrel, inside of which the folding protein is protected. 
C)  Hsp70 is most active during cell division phases. 
D)  Hsp70 assists in protein unfolding by hydrolyzing and remaking the protein peptide bonds.

Question 3

What is the minimum number of amino acids needed to make one turn of an   -helix?

Accepted Answer

A)  3 
B)  4 
C)  6 
D)  7 
A)  3 
B)  4 
C)  6 
D)  7

Question 4

A polypeptide has a high pI value.Which amino acids might comprise it?

Accepted Answer

A)  arginine and lysine residues 
B)  aspartate and glutamate residues 
C)  the large nonpolar amino acids 
D)  a mixture of aspartate and arginine residues 
A)  arginine and lysine residues 
B)  aspartate and glutamate residues 
C)  the large nonpolar amino acids 
D)  a mixture of aspartate and arginine residues

Question 5

What is the pI of the dipeptide shown? (Use the pK as given.)

Accepted Answer

A)  0 
B)  5 
C)  9 
D)  10.5 
A)  0 
B)  5 
C)  9 
D)  10.5

Question 6

Draw the reaction by which a protein disulfide bond forms.

Accepted Answer

The answer of Draw the reaction by which a protein...

Question 7

Why is the amino acid proline not commonly found in   
-helices or   
-sheets? In what secondary structure might proline be commonly found?

Accepted Answer

Because of its cyclic nature,proline has

Question 8

Describe the proposed model of globular protein folding called the nucleation model.

Accepted Answer

In the nucleation model of globular prot

Question 9

Which of the following statements about   -helices and  
-sheets are FALSE?

Accepted Answer

A)  They are both incompatible with the amino acid proline. 
B)  They both interact with other protein elements through amino acid side chains that stick out. 
C)  They both contain a recurring pattern of hydrogen bonds from one peptide bond to another peptide bond. 
D)  They both give rise to similar tertiary structures. 
A)  They are both incompatible with the amino acid proline. 
B)  They both interact with other protein elements through amino acid side chains that stick out. 
C)  They both contain a recurring pattern of hydrogen bonds from one peptide bond to another peptide bond. 
D)  They both give rise to similar tertiary structures.

Question 10

Which of the following statements about the chamber-type chaperone protein GroEL-GroES is correct?

Accepted Answer

A)  GroEL-GroES requires the hydrolysis of multiple ATPs to assist in the folding of a protein. 
B)  GroEL-GroES recycles misfolded proteins by recovering individual amino acids. 
C)  GroEL-GroES assists in protein unfolding by hydrolyzing and remaking the protein peptide bonds. 
D)  GroEL-GroES uses GroEL as a cap, trapping an unfolded protein in the GroES chamber. 
A)  GroEL-GroES requires the hydrolysis of multiple ATPs to assist in the folding of a protein. 
B)  GroEL-GroES recycles misfolded proteins by recovering individual amino acids. 
C)  GroEL-GroES assists in protein unfolding by hydrolyzing and remaking the protein peptide bonds. 
D)  GroEL-GroES uses GroEL as a cap, trapping an unfolded protein in the GroES chamber.

Question 11

List the levels of protein structure and give a brief description of each.

Accepted Answer

1.Primary-amino acid sequence from the N

Question 12

The following amino acid is discovered in a newly isolated protein.What would it be called,and does it represent a new amino acid?

Accepted Answer

The amino acid looks like a modified ser

Question 13

If the isoelectric point (pI)for an amino acid is at point A,what is the charge on the amino acid at point B?

Accepted Answer

A)  0 
B)  -2 
C)  +2 
D)  -1 
A)  0 
B)  -2 
C)  +2 
D)  -1

Question 14

Use the theoretical Ramachandran plot at the top to evaluate the two experimental plots on the bottom.Describe the likely secondary structures found in each experimental plot.

Accepted Answer

The middle Ramachandran plot is consiste

Question 15

What is the difference between clamp-type and chamber-type chaperone proteins?

Accepted Answer

A)  One uses ATP and the other does not. 
B)  One folds proteins, whereas the other just protects them from unfolding. 
C)  They are shaped differently. 
D)  One type is found extracellularly and one intracellularly. 
A)  One uses ATP and the other does not. 
B)  One folds proteins, whereas the other just protects them from unfolding. 
C)  They are shaped differently. 
D)  One type is found extracellularly and one intracellularly.

Question 16

An   -helix has the sequence: NH3+-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-.The carbonyl oxygen (in the peptide bond)of the histidine residue is hydrogen bonded to the amide
Nitrogen of

Accepted Answer

A)  Asp. 
B)  Lys. 
C)  Trp. 
D)  Ala. 
A)  Asp. 
B)  Lys. 
C)  Trp. 
D)  Ala.

Question 17

Describe generally how a gain-of-function protein folding disease can lead to cell death.

Accepted Answer

A gain-of-function folding disease gener

Question 18

It is important for cells to degrade misfolded proteins.If misfolded proteins are not degraded,the misfolded proteins may

Accepted Answer

A)  waste excessive ATP in attempts to refold them. 
B)  aggregate and interfere with normal cellular function. 
C)  eventually refold, but not until excessive and sometimes fatal levels of cellular energy are spent. 
D)  be excreted from the cell rather than recycled for building blocks. 
A)  waste excessive ATP in attempts to refold them. 
B)  aggregate and interfere with normal cellular function. 
C)  eventually refold, but not until excessive and sometimes fatal levels of cellular energy are spent. 
D)  be excreted from the cell rather than recycled for building blocks.

Question 19

Use the two-stranded antiparallel   
-sheet below and drawn in a   
-turn.

Accepted Answer

The answer of Use the two-stranded antiparallel   
-sheet...

Question 20

Which statement about the   -helix is true?

Accepted Answer

A)  The hydrophobic interior of  
-helices is stabilized by the side chains of hydrophobic amino acids. 
B)  The amino acid side chains point out to the sides with every third amino acid roughly lining up on one side of the helix. 
C)    -Helices have backbone amide groups that are hydrogen bonded to amino acid side chains. 
D)    -Helices have 5 amino acids per one turn of the helix. 
A)  The hydrophobic interior of  
-helices is stabilized by the side chains of hydrophobic amino acids. 
B)  The amino acid side chains point out to the sides with every third amino acid roughly lining up on one side of the helix. 
C)    -Helices have backbone amide groups that are hydrogen bonded to amino acid side chains. 
D)    -Helices have 5 amino acids per one turn of the helix.

Exam 4: Protein Structure

Which of the following statements about -sheet structures is true?

Which of the following statements about the clamp-type chaperone protein Hsp70 is correct?

What is the minimum number of amino acids needed to make one turn of an -helix?

A polypeptide has a high pI value.Which amino acids might comprise it?

What is the pI of the dipeptide shown? (Use the pK as given.)

Draw the reaction by which a protein disulfide bond forms.

Why is the amino acid proline not commonly found in -helices or -sheets? In what secondary structure might proline be commonly found?

Describe the proposed model of globular protein folding called the nucleation model.

Which of the following statements about -helices and -sheets are FALSE?

Which of the following statements about the chamber-type chaperone protein GroEL-GroES is correct?

List the levels of protein structure and give a brief description of each.

The following amino acid is discovered in a newly isolated protein.What would it be called,and does it represent a new amino acid?

If the isoelectric point (pI)for an amino acid is at point A,what is the charge on the amino acid at point B?

Use the theoretical Ramachandran plot at the top to evaluate the two experimental plots on the bottom.Describe the likely secondary structures found in each experimental plot.

What is the difference between clamp-type and chamber-type chaperone proteins?

An -helix has the sequence: NH3+-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-.The carbonyl oxygen (in the peptide bond)of the histidine residue is hydrogen bonded to the amide Nitrogen of

Describe generally how a gain-of-function protein folding disease can lead to cell death.

It is important for cells to degrade misfolded proteins.If misfolded proteins are not degraded,the misfolded proteins may

Use the two-stranded antiparallel -sheet below and drawn in a -turn.

Which statement about the -helix is true?

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

An -helix has the sequence: NH₃₊-Ser-Glu-Gly-Asp-Trp-Gln-Leu-His-Val-Phe-Ala-Lys-Val-Glu-COO-.The carbonyl oxygen (in the peptide bond)of the histidine residue is hydrogen bonded to the amide Nitrogen of