Question 1

Addition of low salt concentrations to a protein-containing solution,

Accepted Answer

A)  hydrophobic interactions among protein molecules increase 
B)  solubility of proteins in solution decreases 
C)  the solution has relatively low ionic strength 
D)  Both A and B 
E)  All of the above 
A)  hydrophobic interactions among protein molecules increase 
B)  solubility of proteins in solution decreases 
C)  the solution has relatively low ionic strength 
D)  Both A and B 
E)  All of the above

Question 2

Which is NOT included among the hydrodynamic properties of particles such as proteins in aqueous solution?

Accepted Answer

A)  viscosity 
B)  sedimentation coefficient 
C)  diffusion coefficient 
D)  secondary structure 
E)  hydrodynamic radius 
A)  viscosity 
B)  sedimentation coefficient 
C)  diffusion coefficient 
D)  secondary structure 
E)  hydrodynamic radius

Question 3

If the following mixture of proteins was applied to a size-exclusion chromatography column, what would be the order of elution?
Proteins with molecular weights: myoglobin (17.7 kDa), hemoglobin (64.5 kDa), lysozyme (14.3 kDa) and triose phosphate isomerase (57.4 kDa)

Accepted Answer

A)  lysozyme, myoglobin, triose phosphate isomerase, hemoglobin 
B)  triose phosphate isomerase, hemoglobin, lysozyme, myoglobin 
C)  hemoglobin, myoglobin, lysozyme, triose phosphate isomerase 
D)  hemoglobin, triose phosphate isomerase, myoglobin, lysozyme, 
E)  cannot be determined 
A)  lysozyme, myoglobin, triose phosphate isomerase, hemoglobin 
B)  triose phosphate isomerase, hemoglobin, lysozyme, myoglobin 
C)  hemoglobin, myoglobin, lysozyme, triose phosphate isomerase 
D)  hemoglobin, triose phosphate isomerase, myoglobin, lysozyme, 
E)  cannot be determined

Question 4

Which is a disadvantage to using bacteria as a source of proteins for purification?

Accepted Answer

A)  Molecular biology techniques can be used to overexpress the protein in these cells 
B)  Proteins can be extracted from the cells themselves, or from the media in which the cells are grown 
C)  differences in post-transcriptional modifications may occur 
D)  They grow more quickly than plant or animal tissue 
E)  There are fewer ethical issues involved in using bacterial cells for experimentation 
A)  Molecular biology techniques can be used to overexpress the protein in these cells 
B)  Proteins can be extracted from the cells themselves, or from the media in which the cells are grown 
C)  differences in post-transcriptional modifications may occur 
D)  They grow more quickly than plant or animal tissue 
E)  There are fewer ethical issues involved in using bacterial cells for experimentation

Question 5

A researcher biotinylates a protein; this protein can then be purified by passing it through a column packed with resin coated with

Accepted Answer

A)  avidin 
B)  divalent metal cations 
C)  DEAE (diethylaminoethyl groups) 
D)  phenyl groups 
E)  IgG 
A)  avidin 
B)  divalent metal cations 
C)  DEAE (diethylaminoethyl groups) 
D)  phenyl groups 
E)  IgG

Question 6

The most common immunoaffinity column packing is with

Accepted Answer

A)  IgG 
B)  IgA 
C)  IgM 
D)  IgE 
E)  IgD 
A)  IgG 
B)  IgA 
C)  IgM 
D)  IgE 
E)  IgD

Question 7

If it is important that protein stability is maintained through a purification scheme, and little denaturation can be tolerated, your scheme should include the use of

Accepted Answer

A)  CO32- or SO42- 
B)  S2O32- or Cl- 
C)  CO32- or NO3- 
D)  I- or SCN- 
E)  H2PO4- or F- 
A)  CO32- or SO42- 
B)  S2O32- or Cl- 
C)  CO32- or NO3- 
D)  I- or SCN- 
E)  H2PO4- or F-

Question 8

To facilitate quick analysis of eluents from a chromatographic column, a ___ is installed between the column outflow and collecting tubes.

Accepted Answer

The answer of To facilitate quick analysis of eluents from...

Question 9

Dialysis is used to separate small molecules, like salts, from proteins of interest in a purification scheme. The sample is placed in a dialysis bag, which is immersed in buffer, and the salts will separate and remain in the dialysis bag, which can be removed and discarded.

Accepted Answer

A)  Both sentences are true 
B)  Both sentences are false 
C)  The first sentence is true and the second sentence is false 
D)  The first sentence is false and the second sentence is true 
A)  Both sentences are true 
B)  Both sentences are false 
C)  The first sentence is true and the second sentence is false 
D)  The first sentence is false and the second sentence is true

Question 10

As protein purification proceeds, the number of contaminants increases while the sample is enriched with the desired protein. The purity of the protein is assessed based on "fold purification."

Accepted Answer

A)  Both sentences are true 
B)  Both sentences are false 
C)  The first sentence is true and the second sentence is false 
D)  The first sentence is false and the second sentence is true 
A)  Both sentences are true 
B)  Both sentences are false 
C)  The first sentence is true and the second sentence is false 
D)  The first sentence is false and the second sentence is true

Question 11

High pressure liquid chromatography (HPLC) is not best for separating proteins because

Accepted Answer

A)  it takes too long for high molecular weight molecules to elute 
B)  only highly acidic buffers can be used which alter proteins' primary structures 
C)  its required metal tubing interferes with protein purification 
D)  fast protein liquid chromatography (FPL
C)  runs at higher and more useful pressures 
E)  it cannot be accomplished in the cold 
A)  it takes too long for high molecular weight molecules to elute 
B)  only highly acidic buffers can be used which alter proteins' primary structures 
C)  its required metal tubing interferes with protein purification 
D)  fast protein liquid chromatography (FPL
C)  runs at higher and more useful pressures 
E)  it cannot be accomplished in the cold

Question 12

By increasing the salt concentration in a solution, proteins

Accepted Answer

A)  are somewhat more soluble 
B)  may become very soluble 
C)  may show decreased solubility 
D)  Both A and B 
E)  All of the above 
A)  are somewhat more soluble 
B)  may become very soluble 
C)  may show decreased solubility 
D)  Both A and B 
E)  All of the above

Question 13

Cellular lysis

Accepted Answer

A)  is necessary if the desired protein is released to the media in which cells are grown 
B)  can be accomplished by homogenizing with a centrifuge 
C)  can be accomplished by sonicating the cells with UVB waves 
D)  can be accomplished by using a blender to break open the cells 
E)  All of the above 
A)  is necessary if the desired protein is released to the media in which cells are grown 
B)  can be accomplished by homogenizing with a centrifuge 
C)  can be accomplished by sonicating the cells with UVB waves 
D)  can be accomplished by using a blender to break open the cells 
E)  All of the above

Question 14

How does reverse-phase chromatography differ from HIC?

Accepted Answer

A)  In HIC, eluting buffers can be gentler 
B)  In HIC, the hydrophobic interactions between proteins and resin are weaker 
C)  In HIC, the hydrophobic interactions between proteins and resin are stronger 
D)  In reverse-phase, low MW proteins elute from the column earliest 
E)  Both A and B 
A)  In HIC, eluting buffers can be gentler 
B)  In HIC, the hydrophobic interactions between proteins and resin are weaker 
C)  In HIC, the hydrophobic interactions between proteins and resin are stronger 
D)  In reverse-phase, low MW proteins elute from the column earliest 
E)  Both A and B

Question 15

Dipole-dipole interactions

Accepted Answer

A)  may occur between two groups holding opposite partial charges 
B)  are another name for salt bridges 
C)  are optimized at rather long distances 
D)  are the predominant weak intermolecular force in hydrocarbons 
E)  are optimized by more polar solvents 
A)  may occur between two groups holding opposite partial charges 
B)  are another name for salt bridges 
C)  are optimized at rather long distances 
D)  are the predominant weak intermolecular force in hydrocarbons 
E)  are optimized by more polar solvents

Question 16

Biotin's cellular function includes

Accepted Answer

A)  fatty acid biosynthesis 
B)  gluconeogenesis 
C)  binding circulating lipids 
D)  electron transport in mitochondrial inner membrane 
E)  Both A and B 
A)  fatty acid biosynthesis 
B)  gluconeogenesis 
C)  binding circulating lipids 
D)  electron transport in mitochondrial inner membrane 
E)  Both A and B

Question 17

To monitor the protein concentration of samples eluted during column chromatography, ___ is commonly used, based on the presence of the amino acids such as ___ in the eluted proteins.

Accepted Answer

A)  UV absorbance; phenylalanine 
B)  UV absorbance; alanine 
C)  fluorescence; alanine 
D)  NMR; phenylalanine 
E)  NMR; alanine 
A)  UV absorbance; phenylalanine 
B)  UV absorbance; alanine 
C)  fluorescence; alanine 
D)  NMR; phenylalanine 
E)  NMR; alanine

Question 18

High speed ultracentrifugation

Accepted Answer

A)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >50,000 MW 
B)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >5,000 MW 
C)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >100,000 MW 
D)  does not allow separation of individual proteins 
E)  is commonly used to separate positively-charged proteins from negatively-charged proteins 
A)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >50,000 MW 
B)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >5,000 MW 
C)  allows separation of proteins of varied molecular weights, but only if the proteins in the mixture differ by >100,000 MW 
D)  does not allow separation of individual proteins 
E)  is commonly used to separate positively-charged proteins from negatively-charged proteins

Question 19

A researcher is purifying a structural protein in ovaries. Which would NOT be useful information for a protein purification table?

Accepted Answer

A)  volume (mL) 
B)  protein (mg) 
C)  activity (units) 
D)  purification (fold) 
E)  yield (%) 
A)  volume (mL) 
B)  protein (mg) 
C)  activity (units) 
D)  purification (fold) 
E)  yield (%)

Question 20

A protein rich in tryptophan would be expected to have high spectrophotometric absorbance in the range of

Accepted Answer

A)  20-40 nm 
B)  80-120 nm 
C)  150-200 nm 
D)  270-300 nm 
E)  350-400 nm 
A)  20-40 nm 
B)  80-120 nm 
C)  150-200 nm 
D)  270-300 nm 
E)  350-400 nm

Exam 21: Biomolecule Purification

Addition of low salt concentrations to a protein-containing solution,

Which is NOT included among the hydrodynamic properties of particles such as proteins in aqueous solution?

If the following mixture of proteins was applied to a size-exclusion chromatography column, what would be the order of elution? Proteins with molecular weights: myoglobin (17.7 kDa), hemoglobin (64.5 kDa), lysozyme (14.3 kDa) and triose phosphate isomerase (57.4 kDa)

Which is a disadvantage to using bacteria as a source of proteins for purification?

A researcher biotinylates a protein; this protein can then be purified by passing it through a column packed with resin coated with

The most common immunoaffinity column packing is with

If it is important that protein stability is maintained through a purification scheme, and little denaturation can be tolerated, your scheme should include the use of

To facilitate quick analysis of eluents from a chromatographic column, a ___ is installed between the column outflow and collecting tubes.

Dialysis is used to separate small molecules, like salts, from proteins of interest in a purification scheme. The sample is placed in a dialysis bag, which is immersed in buffer, and the salts will separate and remain in the dialysis bag, which can be removed and discarded.

As protein purification proceeds, the number of contaminants increases while the sample is enriched with the desired protein. The purity of the protein is assessed based on "fold purification."

High pressure liquid chromatography (HPLC) is not best for separating proteins because

By increasing the salt concentration in a solution, proteins

Cellular lysis

How does reverse-phase chromatography differ from HIC?

Dipole-dipole interactions

Biotin's cellular function includes

To monitor the protein concentration of samples eluted during column chromatography, ___ is commonly used, based on the presence of the amino acids such as ___ in the eluted proteins.

High speed ultracentrifugation

A researcher is purifying a structural protein in ovaries. Which would NOT be useful information for a protein purification table?

A protein rich in tryptophan would be expected to have high spectrophotometric absorbance in the range of

The Chemical Foundations of Biochemistry

Nucleic Acids

Proteins I

Proteins Iienzymes

Membranes and an Introduction to Signal Transduction

Carbohydrates I

The Common Catabolic Pathway

Carbohydrates II

Lipids I

Lipids II

Amine Metabolism

Metabolism Integration

Nucleotide Deoxynucleotide Metabolism

Dna Replication, Damage and Repair

Rna Synthesis

Protein

Control of Gene

Determination of Macromolecular Structure

Allosterism and Receptor-Ligand

Designer Proteins and Protein Folding

Bioinformatics and Omics

Signal

Protein Trafficking

Photosynthesis Nitrogen

Filters

To monitor the protein concentration of samples eluted during column chromatography, _ is commonly used, based on the presence of the amino acids such as _ in the eluted proteins.