Question 1

________ is used to estimate the molecular weight of oligomeric proteins,while ________ is used to determine molecular weight of each chain.

Accepted Answer

A) Melting point;SDS-gel electrophoresis 
B) SDS-gel electrophoresis;gel-filtration chromatography 
C) Acrylamide gel electrophoresis;isoelectric focusing 
D) Gel-filtration chromatography;SDS-gel electrophoresis 
E) SDS-gel electrophoresis;NMR 
A) Melting point;SDS-gel electrophoresis 
B) SDS-gel electrophoresis;gel-filtration chromatography 
C) Acrylamide gel electrophoresis;isoelectric focusing 
D) Gel-filtration chromatography;SDS-gel electrophoresis 
E) SDS-gel electrophoresis;NMR

Question 2

In 1962 Kendrew and Perutz won a Nobel Prize for

Accepted Answer

A) solving the structure of collagen by NMR. 
B) determining the structure of the α-helix. 
C) performing the first sequencing of a protein. 
D) determining the structures of myoglobin and hemoglobin by X-ray crystallography. 
A) solving the structure of collagen by NMR. 
B) determining the structure of the α-helix. 
C) performing the first sequencing of a protein. 
D) determining the structures of myoglobin and hemoglobin by X-ray crystallography.

Question 3

Match the protein organization most associated with the term(s)listed below:
-Hydrogen bonds between carbonyl and amino groups

Accepted Answer

A) Secondary 
B) Tertiary 
C) Quaternary 
D) Primary 
A) Secondary 
B) Tertiary 
C) Quaternary 
D) Primary

Question 4

Many proteins have multiple subunits because

Accepted Answer

A) an active site is shared by different subunits. 
B) they are more stable and flexible in movement. 
C) different combinations can perform different functions. 
D) All of the above. 
E) A and C above. 
A) an active site is shared by different subunits. 
B) they are more stable and flexible in movement. 
C) different combinations can perform different functions. 
D) All of the above. 
E) A and C above.

Question 5

In oligomeric proteins all the subunits are always identical.

Accepted Answer

A) True 
 B)False

Question 6

The Bohr effect describes the effect of pH on hemoglobin's ability to bind oxygen.Oxygen binds more tightly at low pH and less tightly at higher pH values.

Accepted Answer

A) True 
 B)False

Question 7

Match each level of organization with a description.
-Secondary structure

Accepted Answer

A) Specific order of amino acids 
B) Multiple subunits are present 
C) Overall shape of a protein 
D) Repeated pattern of folding 
A) Specific order of amino acids 
B) Multiple subunits are present 
C) Overall shape of a protein 
D) Repeated pattern of folding

Question 8

Hydrophobic amino acid sequences in myoglobin are responsible for

Accepted Answer

A) covalent bonding to the heme prosthetic group. 
B) the folding of the polypeptide chain. 
C) the irreversible binding of oxygen. 
D) A and B above. 
A) covalent bonding to the heme prosthetic group. 
B) the folding of the polypeptide chain. 
C) the irreversible binding of oxygen. 
D) A and B above.

Question 9

Which technique is commonly used to determine the three-dimensional conformation of a protein?

Accepted Answer

A) Isoelectric focusing. 
B) The Edman degradation. 
C) SDS-PAGE. 
D) X-ray crystallography. 
A) Isoelectric focusing. 
B) The Edman degradation. 
C) SDS-PAGE. 
D) X-ray crystallography.

Question 10

The hydrophobic crevice of globin prevents complete electron transfer to the oxygen so that the electron returns to the iron atom when oxygen dissociates.

Accepted Answer

A) True 
 B)False

Question 11

Myoglobin has a greater affinity for oxygen than hemoglobin.

Accepted Answer

A) True 
 B)False

Question 12

The native structures of proteins are more stable than non-native conformations;they occupy a low-energy well when folded.

Accepted Answer

A) True 
 B)False

Question 13

Match the protein organization most associated with the term(s)listed below:
-Cystine

Accepted Answer

A) Secondary 
B) Tertiary 
C) Quaternary 
D) Primary 
A) Secondary 
B) Tertiary 
C) Quaternary 
D) Primary

Question 14

An ideal α-helix has a pitch of 0.54 nm and a rise of 0.15 nm.What is the length along the helix axis for a segment of an ideal α-helix that contains 30 amino acids?

Accepted Answer

A) 200 nm 
B) 4.50 nm 
C) 16.20 nm 
D) 55.5 nm 
A) 200 nm 
B) 4.50 nm 
C) 16.20 nm 
D) 55.5 nm

Question 15

Which pair represents different conformations?

Accepted Answer

A) Cis-1,2-dichloroethene and trans-1,2-dichloroethene. 
B) L-glycine and D-glycine. 
C) Eclipsed ethane and staggered ethane. 
D) Pentane and 2-methylbutane. 
A) Cis-1,2-dichloroethene and trans-1,2-dichloroethene. 
B) L-glycine and D-glycine. 
C) Eclipsed ethane and staggered ethane. 
D) Pentane and 2-methylbutane.

Question 16

A tetrameric protein contains

Accepted Answer

A) four different subunits. 
B) four identical subunits. 
C) three subunits and one prosthetic group. 
D) A or B only. 
E) A,B or C. 
A) four different subunits. 
B) four identical subunits. 
C) three subunits and one prosthetic group. 
D) A or B only. 
E) A,B or C.

Question 17

For each term select the description that best describes its contribution to the structure of collagen.
-Glycine

Accepted Answer

A) Forms covalent cross links 
B) Makes the protein rigid 
C) Required for hydroxylation 
D) Allows tightly wound helix formation 
E) Has H bonds which help stabilize the protein 
A) Forms covalent cross links 
B) Makes the protein rigid 
C) Required for hydroxylation 
D) Allows tightly wound helix formation 
E) Has H bonds which help stabilize the protein

Question 18

Collagen is a protein made of a triple helix that is stabilized by

Accepted Answer

A) disulfide bridges. 
B) intrachain hydrogen bonds. 
C) interchain hydrogen bonds. 
D) covalent bonds. 
A) disulfide bridges. 
B) intrachain hydrogen bonds. 
C) interchain hydrogen bonds. 
D) covalent bonds.

Question 19

Conditions in the tissues which enhance the delivery of oxygen by hemoglobin are the presence of

Accepted Answer

A) carbon dioxide. 
B) 2,3 BPG. 
C) protons. 
D) All of the above. 
E) A and B above. 
A) carbon dioxide. 
B) 2,3 BPG. 
C) protons. 
D) All of the above. 
E) A and B above.

Question 20

Which statement is true about disulfide bonds and protein folding?

Accepted Answer

A) Disulfide bonds have no influence on protein folding since they only form after the protein adopts its native conformation. 
B) Proteins occasionally adopt nonnative conformations and form improper disulfide bonds that can be reversed by the enzyme protein disulfide isomerase. 
C) The folding of the native conformation is influenced more strongly by the formation of disulfide bonds than by the primary structure of a protein. 
D) If a protein forms an improper disulfide bond it is irreversibly inactivated and must be targeted by the cell for degradation. 
A) Disulfide bonds have no influence on protein folding since they only form after the protein adopts its native conformation. 
B) Proteins occasionally adopt nonnative conformations and form improper disulfide bonds that can be reversed by the enzyme protein disulfide isomerase. 
C) The folding of the native conformation is influenced more strongly by the formation of disulfide bonds than by the primary structure of a protein. 
D) If a protein forms an improper disulfide bond it is irreversibly inactivated and must be targeted by the cell for degradation.

Exam 4: Proteins: Three-Dimensional Structure and Function

________ is used to estimate the molecular weight of oligomeric proteins,while ________ is used to determine molecular weight of each chain.

In 1962 Kendrew and Perutz won a Nobel Prize for

Match the protein organization most associated with the term(s)listed below: -Hydrogen bonds between carbonyl and amino groups

Many proteins have multiple subunits because

In oligomeric proteins all the subunits are always identical.

The Bohr effect describes the effect of pH on hemoglobin's ability to bind oxygen.Oxygen binds more tightly at low pH and less tightly at higher pH values.

Match each level of organization with a description. -Secondary structure

Hydrophobic amino acid sequences in myoglobin are responsible for

Which technique is commonly used to determine the three-dimensional conformation of a protein?

The hydrophobic crevice of globin prevents complete electron transfer to the oxygen so that the electron returns to the iron atom when oxygen dissociates.

Myoglobin has a greater affinity for oxygen than hemoglobin.

The native structures of proteins are more stable than non-native conformations;they occupy a low-energy well when folded.

Match the protein organization most associated with the term(s)listed below: -Cystine

An ideal α-helix has a pitch of 0.54 nm and a rise of 0.15 nm.What is the length along the helix axis for a segment of an ideal α-helix that contains 30 amino acids?

Which pair represents different conformations?

A tetrameric protein contains

For each term select the description that best describes its contribution to the structure of collagen. -Glycine

Collagen is a protein made of a triple helix that is stabilized by

Conditions in the tissues which enhance the delivery of oxygen by hemoglobin are the presence of

Which statement is true about disulfide bonds and protein folding?

Introduction to Biochemistry

Water

Amino Acids and the Primary Structures of Proteins

Properties of Enzymes

Mechanisms of Enzymes

Coenzymes and Vitamins

Carbohydrates

Lipids and Membranes

Introduction to Metabolism

Glycolysis

Gluconeogenesis, the Pentose Phosphate Pathway, and Glycogen Metabolism

The Citric Acid Cycle

Electron Transport and Atp Synthesis

Photosynthesis

Lipid Metabolism

Amino Acid Metabolism

Nucleotide Metabolism

Nucleic Acids

DNA Replication, repair, and Recombination

Transcription and RNA Processing

Protein Synthesis

Filters

is used to estimate the molecular weight of oligomeric proteins,while is used to determine molecular weight of each chain.