Deck 3: Exploring Proteins and Proteomes

Question 1

Which type of protein purification relies on the attraction of the protein for a particular chemical group?

A) affinity chromatography
B) gel-filtration chromatography
C) HPLC
D) gel electrophoresis
E) isoelectric focusing

Answer 1

A

Question 2

Dithiothreitol or β mercaptoethanol are commonly used to reduce _______________ bonds.

Answer 2

disulfide

Question 3

__________________ gels are often used as the media for electrophoretic techniques such as SDS-PAGE and isoelectric focusing.

Answer 3

Polyacrylamide

Question 4

_____ can be added prior to gel electrophoresis to fully denature proteins.

A) Coomassie blue
B) polyacrylamide
C) SDS
D) $\beta$ -mercaptoethanol
E) All of the answers are correct.

Question 5

What technique would be used to separate proteins with different sedimentation coefficients?

A) MALDI-TOF mass spectrometry
B) zonal centrifugation
C) HPLC
D) gel-filtration chromatography
E) All of the answers are correct.

Question 6

In the Edman procedure for peptide sequence,phenyl isothiocyanate is used to selectively remove the __________________ residue as a PTH-derivative.

Question 7

What technique can be used to determine the mass of a protein without knowing the identity of the molecule?

A) affinity chromatography
B) ion exchange chromatography
C) polyacrylamide gel electrophoresis
D) MALDI-TOF mass spectrometry
E) western blot

Question 8

_____ is the term to describe an original amino acid sequence for an uncleaved protein.

A) Apoprotein
B) Holoprotein
C) Nascent
D) Protomer
E) None of the answers is correct.

Question 9

Long proteins are often treated with the enzyme ______________,which cleaves the protein into smaller,easily analyzed peptides.

Question 10

Which of the following is often the first step in protein purification from a homogenate?

A) ion exchange chromatography
B) gel-filtration chromatography
C) HPLC
D) centrifugation
E) gel electrophoresis

Question 11

The unit for sedimentation coefficients is the _____.

A) Newton
B) radian
C) g
D) Svedberg
E) None of the answers is correct.

Question 12

The mobility of proteins in SDS-PAGE is inversely proportional to the _____________.

Question 13

Which of the following are used to sequence entire proteins?

A) affinity peptides
B) circular peptides
C) overlap peptides
D) labeled peptides
E) synthetic peptides

Question 14

The ratio of enzyme activity relative to total protein is called _____.

A) inherent activity
B) specific activity
C) explicit activity
D) exclusive activity
E) purified activity

Question 15

The advantage to ______________________protein synthesis is that the desired product is bound to beads and excess reagents can be easily removed at each step.

Question 16

Mass spectrometric techniques are critical in _________________research,which explores the proteins present in a cell,because it is possible to analyze constituents of large macromolecular assemblies.

Question 17

Another name for an antigenic determinant is _____.

A) epitope
B) epimer
C) epinephrine
D) epidemic
E) None of the answers is correct.

Question 18

Polypeptides can be fragmented into smaller peptides by cleavage with trypsin,which hydrolyzes the peptide bond at the C-terminal side of __________________ residues.

Question 19

Molecular exclusion or gel-filtration chromatography separates molecules on the basis of __________________.

Question 20

Proteins can be separated from small molecules and ions through a semipermeable membrane by __________________.

Question 21

A technique that can be used to study three-dimensional protein structure is

A) one-dimensional NMR spectroscopy
B) fluorescent microscopy
C) x-ray crystallography
D) Western blotting
E) ion-exchange chromatography

Question 22

How can a protein's isoelectric point be used in protein purification (i.e.,isoelectric focusing)?

Question 23

Proteins that are not catalysts are often probed or assayed using

A) antibody binding assays.
B) catalytic activity.
C) genomic analysis.
D) None of the answers is correct.
E) All of the answers are correct.

Question 24

An ELISA can be used for

A) quantitative analysis.
B) size analysis.
C) protein sequencing
D) All of the answers are correct.
E) None of the answers is correct.

Question 25

Protein databases

A) can identify proteins from small stretches of amino acid sequences.
B) are not useful in proteomics studies due to the complexities of the proteome.
C) are determined from sequence data only, never deduced from genomic data.
D) None of the answers is correct.
E) All of the answers are correct.

Question 26

Which technique cannot be used for quantitative analysis?

A) x-ray crystallography
B) ELISA
C) absorbance spectroscopy
D) All of the answers are correct.
E) None of the answers is correct.

Question 27

Which of the following affect the sedimentation rate of a particle?

A) mass
B) shape
C) the density of the solution
D) All of the answers are correct.
E) mass and shape

Question 28

What types of molecules can serve as antigens?

A) proteins
B) polysaccharides
C) metal ions
D) All of the answers are correct.
E) proteins and polysaccharides

Question 29

Two-dimensional electrophoresis is a combination of what two techniques?

A) ion-exchange chromatography and affinity chromatography
B) ion-exchange chromatography and SDS-PAGE
C) SDS-PAGE and affinity chromatography
D) isoelectric focusing and SDS-PAGE
E) isoelectric focusing and ion-exchange chromatography

Question 30

What is the purpose of determining the specific activity,yield,and purification level of a protein purification protocol?

Question 31

Cyanogen bromide cleaves the peptide bond at

A) the carboxyl side of Arg and Lys residues.
B) the carboxyl side of Met residues.
C) the amino terminus.
D) None of the answers is correct.
E) All of the answers are correct.

Question 32

The use of synthetic peptides includes

A) use as antigens for making antibodies.
B) drugs.
C) "hooks" for use in affinity purification.
D) All of the answers are correct.
E) use as antigens for making antibodies and "hooks" for use in affinity purification.

Question 33

How do gel-filtration and ion-exchange chromatography differ?

Question 34

Techniques that can be used to obtain information about protein shape are

A) x-ray crystallography.
B) NOESY NMR spectroscopy.
C) SDS-PAGE.
D) x-ray crystallography and NOESY NMR spectroscopy.
E) All the answers are correct.

Question 35

A technique used to identify proteins after gel electrophoresis,which employs antibodies in the detection process,is known as

A) northern blot
B) southwestern blot
C) western blot
D) Southern blot
E) None of the answers is correct.

Question 36

What is the advantage of adding SDS to gel electrophoresis?

A) SDS colors the proteins for visualization.
B) SDS reduces disulfide bonds.
C) SDS allows proteins to be separated on the basis of approximate mass.
D) None of the answers is correct.
E) All of the answers are correct.

Question 37

Why is an assay necessary for protein purification studies?

Question 38

Which of the following techniques can be used to determine mass to charge ratio of a molecule?

A) Edman degradation
B) affinity chromatography
C) diagonal electrophoresis
D) MALDI-TOF
E) SDS-PAGE

Question 39

How is lactate dehydrogenase assayed?

Question 40

When enzymes are purified,the assay is often based on

A) light absorbance.
B) catalytic activity.
C) pH.
D) temperature changes.
E) mRNA levels.

Question 41

What is one advantage of using the recombinant DNA methods to determine protein sequences?

Question 42

Briefly describe how an ELISA works.

Question 43

How can the amino acid sequences be used to design a DNA probe?

Question 44

Why are monoclonal antibodies more useful than polyclonal antibodies?

Question 45

How can recombinant DNA technology aid in protein purification?

Question 46

Describe the Edman degradation method for protein-sequence analysis.

Question 47

How are monoclonal antibodies made?

Question 48

What type of information can be obtained from ultracentrifugation?

Question 49

What are some of the advantages and drawbacks of NMR spectroscopy compared to x-ray crystallography?

Question 50

After a protein is purified,what is the next step in determining the structure of a protein by x-ray crystallography?