Question 1

Important steps in sequencing pure proteins include all of these except:

Accepted Answer

A)  Determining the amino acid composition 
B)  Determining the isoionic pH of the protein 
C)  Breaking the protein into smaller peptides 
D)  Determining the amino acids on the ends of the protein 
E)  Determining the amino acids on the ends of the smaller peptides 
A)  Determining the amino acid composition 
B)  Determining the isoionic pH of the protein 
C)  Breaking the protein into smaller peptides 
D)  Determining the amino acids on the ends of the protein 
E)  Determining the amino acids on the ends of the smaller peptides

Question 2

Elution of proteins by means of a pH gradient would work best with this type of column:

Accepted Answer

A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange 
A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange

Question 3

Which substance would you expect to be eluted first from a molecular sieve column with a suitable degree of crosslinking?

Accepted Answer

A)  hemoglobin 
B)  myoglobin 
C)  2,3- bis phosphoglycerate 
D)  all would elute at the same rate 
A)  hemoglobin 
B)  myoglobin 
C)  2,3- bis phosphoglycerate 
D)  all would elute at the same rate

Question 4

When end-group analysis was done on the protein insulin, the results indicated that both glycine and phenylalanine were N-terminal amino acids and both asparagine and alanine were C-terminal amino acids. These results indicate that

Accepted Answer

A)  the experiment was done incorrectly 
B)  no conclusions can be drawn 
C)  there were impurities in the sample 
D)  insulin consists of two polypeptide chains 
A)  the experiment was done incorrectly 
B)  no conclusions can be drawn 
C)  there were impurities in the sample 
D)  insulin consists of two polypeptide chains

Question 5

The following methods are useful for cell homogenization:

Accepted Answer

A)  Sonication. 
B)  Freezing and thawing. 
C)  Detergents. 
D)  Enzymes. 
E)  All of these are correct. 
A)  Sonication. 
B)  Freezing and thawing. 
C)  Detergents. 
D)  Enzymes. 
E)  All of these are correct.

Question 6

When electrophoretic separations are done based on molecular weight, the distance that a molecule moves can be graphed as a straight line when compared to:

Accepted Answer

A)  the MW of the proteins 
B)  the negative of the MW of the proteins 
C)  the log of the MW of the proteins 
D)  none of these 
A)  the MW of the proteins 
B)  the negative of the MW of the proteins 
C)  the log of the MW of the proteins 
D)  none of these

Question 7

A chromatography technique where a solution of nonpolar compounds is put through a column that has a nonpolar liquid immobilized on an inert matrix is which type of chromatography?

Accepted Answer

A)  Gel filtration 
B)  Ion exchange 
C)  Affinity 
D)  HPLC 
E)  Reverse Phase HPLC 
A)  Gel filtration 
B)  Ion exchange 
C)  Affinity 
D)  HPLC 
E)  Reverse Phase HPLC

Question 8

The isoelectric point is

Accepted Answer

A)  the pH at which a substance has no net charge 
B)  the pH at which a substance has a net positive charge 
C)  the pH at which a substance has a net negative charge 
D)  the pH at which a substance has no charge groups of any kind 
A)  the pH at which a substance has no net charge 
B)  the pH at which a substance has a net positive charge 
C)  the pH at which a substance has a net negative charge 
D)  the pH at which a substance has no charge groups of any kind

Question 9

What tends to happen to the percent recovery during a protein's purification?

Accepted Answer

A)  The number usually steadily increases during the purification. 
B)  The number usually steadily decreases during the purification. 
C)  The number usually stays fairly constant during the purification. 
D)  There is no general trend for percent recovery during a protein purification. 
A)  The number usually steadily increases during the purification. 
B)  The number usually steadily decreases during the purification. 
C)  The number usually stays fairly constant during the purification. 
D)  There is no general trend for percent recovery during a protein purification.

Question 10

It is impossible to sequence a protein if you do not have overlapping sequences to work with.

Accepted Answer

A) True 
 B)False

Question 11

The following are all principles on which to base electrophoresis except:

Accepted Answer

A)  Molecular size 
B)  Isoionic pH or pI 
C)  Net charge 
D)  Binding to a substrate 
E)  Shape 
A)  Molecular size 
B)  Isoionic pH or pI 
C)  Net charge 
D)  Binding to a substrate 
E)  Shape

Question 12

In all forms of chromatography one way of identifying eluted substances is by

Accepted Answer

A)  fluorescence spectroscopy 
B)  comparison with standards 
C)  radioactive labeling 
D)  treating fractions with a reagent that will cause a color change 
A)  fluorescence spectroscopy 
B)  comparison with standards 
C)  radioactive labeling 
D)  treating fractions with a reagent that will cause a color change

Question 13

Exhibit 5A The following diagram shows the anode, cathode, and pH gradient of an isoelectric focusing bed:   Refer to Exhibit 5A. If the amino acid glycine were placed in the bed where the pH is 7, and the current were turned on, it would migrate closest to which of the following positions?

Accepted Answer

A)  pH 4 
B)  pH 6 
C)  pH 8 
D)  pH 10 
A)  pH 4 
B)  pH 6 
C)  pH 8 
D)  pH 10

Question 14

Studying the entire complement of proteins being produced by a cell is called

Accepted Answer

A)  genomics 
B)  proteomics 
C)  ELISA 
D)  western blot 
A)  genomics 
B)  proteomics 
C)  ELISA 
D)  western blot

Question 15

Which of the following are principles on which to base column chromatography?

Accepted Answer

A)  Molecular size 
B)  Isoionic pH or pI 
C)  Ion exchange 
D)  Both molecular size and ion exchange 
E)  All of these 
A)  Molecular size 
B)  Isoionic pH or pI 
C)  Ion exchange 
D)  Both molecular size and ion exchange 
E)  All of these

Question 16

In affinity chromatography

Accepted Answer

A)  there is nonspecific binding of proteins to column material 
B)  only minor purifications can be obtained 
C)  the mobile phase is always pure water 
D)  the ligand is always specific for one type of protein to be bound 
E)  there can be molecule specific ligands or group specific ligands 
A)  there is nonspecific binding of proteins to column material 
B)  only minor purifications can be obtained 
C)  the mobile phase is always pure water 
D)  the ligand is always specific for one type of protein to be bound 
E)  there can be molecule specific ligands or group specific ligands

Question 17

Which separates on the basis of molecular weight?

Accepted Answer

A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange 
A)  Gel filtration 
B)  Affinity chromatography 
C)  Cation exchange 
D)  Anion exchange 
E)  Cation or anion exchange

Question 18

Methods for breaking proteins into smaller peptides include all of the following except:

Accepted Answer

A)  Digestion with chymotrypsin 
B)  Cyanogen Bromide treatment 
C)  Digestion with Trypsin 
D)  Edmann degradation 
E)  All of the above create short peptides suitable for sequencing 
A)  Digestion with chymotrypsin 
B)  Cyanogen Bromide treatment 
C)  Digestion with Trypsin 
D)  Edmann degradation 
E)  All of the above create short peptides suitable for sequencing

Question 19

How many bands would be produced when hemoglobin is subjected to SDS-PAGE?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  2, but only if the size of the pores in the gel would allow two proteins of slightly different size to be separated 
A)  1 
B)  2 
C)  3 
D)  4 
E)  2, but only if the size of the pores in the gel would allow two proteins of slightly different size to be separated

Question 20

What is the distinguishing feature of affinity chromatography?

Accepted Answer

The distinguishing feature of affinity c

Exam 5: Protein Purification and Characterization Techniques

Important steps in sequencing pure proteins include all of these except:

Elution of proteins by means of a pH gradient would work best with this type of column:

Which substance would you expect to be eluted first from a molecular sieve column with a suitable degree of crosslinking?

When end-group analysis was done on the protein insulin, the results indicated that both glycine and phenylalanine were N-terminal amino acids and both asparagine and alanine were C-terminal amino acids. These results indicate that

The following methods are useful for cell homogenization:

When electrophoretic separations are done based on molecular weight, the distance that a molecule moves can be graphed as a straight line when compared to:

A chromatography technique where a solution of nonpolar compounds is put through a column that has a nonpolar liquid immobilized on an inert matrix is which type of chromatography?

The isoelectric point is

What tends to happen to the percent recovery during a protein's purification?

It is impossible to sequence a protein if you do not have overlapping sequences to work with.

The following are all principles on which to base electrophoresis except:

In all forms of chromatography one way of identifying eluted substances is by

Exhibit 5A The following diagram shows the anode, cathode, and pH gradient of an isoelectric focusing bed: Refer to Exhibit 5A. If the amino acid glycine were placed in the bed where the pH is 7, and the current were turned on, it would migrate closest to which of the following positions?

Studying the entire complement of proteins being produced by a cell is called

Which of the following are principles on which to base column chromatography?

In affinity chromatography

Which separates on the basis of molecular weight?

Methods for breaking proteins into smaller peptides include all of the following except:

How many bands would be produced when hemoglobin is subjected to SDS-PAGE?

What is the distinguishing feature of affinity chromatography?

Biochemistry and the Organization of Cells

Water the Solvent for Biochemical Reactions

Amino Acids and Peptides

The Three Dimensional Structure of Proteins

The Behavior of Proteins Enzymes

The Behavior of Proteins Enzymes Mechanisms and Control

Lipids and Proteins Are Associated in Biological Membranes

Nucleic Acids How Structure Conveys Information

Biosynthesis of Nucleic Acids Replication

Transcription of the Genetic Code the Biosynthesis of Rna

Protein Synthesis Translation of the Genetic Message

Nucleic Acid Biotechnology Techniques

Viruses Cancer and Immunology

The Importance of Energy Changes and Electron Transfer in Metabolism

Carbohydrates

Glycolysis

Storage Mechanisms and Control in Carbohydrate Metabolism

The Citric Acid Cycle

Electron Transport and Oxidative Phosphorylation

Lipid Metabolism

Photosynthesis

The Metabolism of Nitrogen

Integration of Metabolism Cellular Signaling

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