Chemistry Quiz 3

1. If the viscosity of the support medium used in a protein electrophoresis system is too high (thick), the migration rate will

Increase

Decrease

Not be affected

2. The isoelectric point (pI) of a protein is the pH at which:

The protein has no net charge

The protein has a negative charge

The protein has a positive charge

A protein migrates best in electrophoresis

3. SDS Page electrophoresis is used to:

Determine the charge of a protein

Determine the molecular weight of a protein

Isolate a protein which is not denatured by process

4. An epitope is:

A cell wall component

RBC antigen binding site

Antibody binding site on an antigen

WBC binding site

Submit

6. Analytical Procedures that use enzymes as reagents add the enzymes in excess to ensure completion of reaction in a short time period

True

False

7. In an electrophoresis system, the __________ is the negative electrode.

Anode

Optode

Cathode

Diode

8. The advantage of enzyme immunoassays over fluorescent immunoassays is that enzyme immunoassays:

Can be more sensitive due to the conversion of multiple substrate molecules to a multiple product molecules

Do not require antibodies

Do not require antigens

Do not require the use of an antibody-antigen reaction

9. In electrophoresis, the mobility of the serum proteins is increased when the:

Current is decreased

Ionic strength of the buffer is decreased

Current is increased

Voltage is decreased

10. Binding of Antigens to Antibodies does not involve which of the following bonds:

Electrostatic Interactions

Hydrophobic Interactions

Hydrogen Bonds

Covalent Interactions

11. Binding of antigens to antibodies does not involve which of the following bonds:

Electrostatic interactions

Hydrophobic interactions

Hydrogen bonds

Covalent Interactions

Van der Waals forces

12. Which one of the following separation techniques could be used instead if you were looking to separate molecules based on molecular weight?

Partition

Affinity

Adsorption

Size Exclusion

13. You set up a morning protein electrophoresis run and are going for a coffee break. You return 45 mins later, you stain the gel and notice that the bands did not migrate very far from the point of application. What is the likely explanation?

A chemical reaction occurred between the buffer and all samples

The current or voltage on the power supply was set too low

Too much sample was applied to the gel

The electrophoresis chamber was not connected to a power supply

14. In electrophoresis - the function of the buffer is to:

Carry the applied current

Establish charge of the solute

Both a and b

Maintain the stability of the agarose gel

15. 2D-Immunoelectrophoresis electrophoresis is a technique in which antigens are separated by:

By charge alone

By size alone

By size and isoelectric point

Isoelectric point alone

16. You are preparing a placental tissue for separation and isolation of a specific enzyme. The enzyme has a negative charge, so you want to use chromatography to perform your task. Following homogenization, the tissue is reduced to a large volume of liquid. Which of the following separation mechanisms would be most useful?

Ion-exchange

Partition

Affinity

Adsorption

17. In antigen (Ag) antibody (Ab) reactions, the Ag-Ab complex precipitation occurs:

Decreasing concentration of Ag

At the Ag-Ab equivalence point

Increasing concentration of Ag

Decreasing concentration of Ab

18. Heat generated in an electrophoretic unit is equal to ?

Voltage x Current x Time

Voltage x Current / Time

Current x Time

Voltage x Time

19. Which of the following statements best defines Luminescence?

The emission of light by a substance after absorption of excitation energy

Emission of light due to nonthermal process, a chemical reaction, or the absorption of ionizing radiation

This light is absorbed by the ground state atoms

Emission of light requiring a light source

20. If an electrophoretic buffer were diluted before use instead of using it at normal strength, how would electrophoresis be affected?

Increased migration rate of protein

Decreased migration rate of protein

No change in the rate of migration of protein

21. Which of the following is NOT a homogeneous method:

EMIT

FPIA

ELISA

CEDIA

22. Which of the following statements is/are true with respect to proteins?

Proteins are amphoteric compounds

Proteins are lipid soluble

Protein charge is based on pH of the medium

Only a and b

Only a and c

23. Which of the following is a fluorescent label?

Alkaline Phosphatase

Ruthenium

Fluoroescein Isothyocyanate

Acridium Esters with H2O2

24. In a sandwich technique for a specific antigen:

The antigen must have one epitope

The antigen must have more than one epitope

The antigen must not have an epitope

The antigen must not bind to the secondary antibody

25. Affinity is defined as the:

Strength of the reaction between a multi-variant antigenic site and a single antibody combining site

Strength of the reaction between a single antigenic site and a multi-variant antibody combining site

Strength of the reaction between a single antigenic site and a single antibody combining site

Overall strength of binding between a multi-variant antigenic site and a multivalent antibody site.

26. Isoelectric focusing proteins:

Precipitate out of solution when pH of gradient is above the protein pI

Precipitate out of solution when pH of gradient is below the protein pI

Precipitate out of solution when pH of gradient is the same as the protein pI

Precipitate out of solution when fixative buffer is added

27. The term avidity is used to designate:

The strength of binding of a multivalent antigen with antibody

Strength of binding between the antibody and the multivalent antigen

Analytical sensitivity of the assay

Analytical specificity of assay

28. How does the net charge of the proteins in a sample affect the electrophoretic mobility of protein fractions?

It is inversely proportional to electrophoretic mobility

It is directly proportional to electrophoretic mobility

It is equal to the electrophoretic mobility

There is no relationship between net charge and electrophoretic mobility

29. In affinity chromatography, proteins are separated:

By charge

By size

By molecular weight

Binding to a specific ligand

30. Another way that bias can be defined is as ________ error.

Random

Systematic

Analytical

Clinical

31. In a competitive heterogeneous immunoassay of Ag's in a serum sample:

32. In a sandwich assay of the concentration of a specific antigen present in a serum sample, the response will:

Decrease with the level of antigens in the serum

Increase with the level of antigens in the serum

Not change the level of antigens in the serum

Is dependent on the concentration of labeled antigens

33. In SDS PAGE electrophoresis, which of the following statements is true:

The proteins are separated based on their charge-to-mass ratio

SDS carries a positive charge

The proteins are separated based on their size alone

The proteins are separated based on their charge alone

34. What is the importance of the ionic strength of the buffer used in gel electrophoresis?

No migration will occur if a buffer's ionic strength is too high

Increased ionic strength will lead to a backward electrophoretic pattern

The protein will become denatured if the ionic strength of the buffer is too high

Staining of the protein fractions will not occur if the ionic strength in the buffer is too high

35. The rate of rotation of molecules in a liquid at a constant temperature is:

Directly proportional to size

Inversely proportional to size

Directly proportional to rate of diffusion

36. Antigen-antibody complexes can be dissociated by:

High pH

High salt concentrations

Low pH

All of the above

37. Which of the following immunoassay techniques utilizes genetically engineered enzyme fragments in the assay design:

EMIT

CEDIA

ELISA

FPIA

38. Immunofixation electrophoresis:

Combines the techniques of zone electrophoresis, isotachophoresis, isoelectric focusing, and gel electrophoresis in small-bore fused silica capillary tubes

Involves exposure of electrophoresed proteins to antisera against different immunoglobulin heavy and light chains with resultant precipitation

Uses electrophoresis in two dimensions to assess global changes in protein expression

39. At high concentrations, added salt:

Increases the solubility of macromolecules

Decreases the solubility of macromolecules

Sustains the solvation of the protein

Prevents aggregation of the protein

40. Isoelectric focusing is a technique in which proteins are separated:

By charge alone

By size alone

By pH and charge

By pH and size

41. In SDS-PAGE electrophoresis every protein _ which will cause all proteins to migrate towards the cathode with a rate ______.

Will carry a different charge, dependent on size

Will vary in size, dependent on size alone.

Will have the same charge to mass ratio, that is dependent on their sizes

Will vary in charge, dependent on charge alone

42. In competitive heterogeneous methods:

The antibody is in excess

The antigen is in excess

Involves secondary labeled antibody

ELISA is the prototype

43. Which of the following statements is NOT true with respect to chemiluminescence:

Chemiluminescence is a multiwavelength type of emmission

Reaction typically carried out directly in front of the detector

Higher photon collection efficiency can be achieved than in fluorescence analysis

Reaction can take place in gas phase

44. Which of the following is not correct with regards to fluorescent immunoassays?

Uses fluorochromes such as FITC

Involves the conjugation of fluorochromes to antibodies or antigens

Uses enzyme linked antibodies of antigens

Method requires use of a fluorescence detector

45. In size exclusion chromatography, the larger molecules

Are hung up within the column

Are eluted off the column after being captured

Are the first fractions collected off the column

46. The calibration curve (response) in EMIT methods:

Decrease with increasing antigen concentration

Increase with increasing antigen concentration

Increase with increasing antibody concentration

Decrease with increasing antibody concentration

47. At a pH of 4.0, the

Carboxyl and amino groups of an amino acid become unprotonated, causing the amino acid to be anionic

Carboxyl and amino groups of an amino acid become protonated, causing the amino acid to be cationic

Carboxyl group of an amino acid is dissociated and the amino group is protonated

Amino group of an amino acid is dissociated and the carboxyl group is protonated

48. In isoelectric focusing, the gel within the column consists of:

PH adjusted agarose gel aliphatic

Aliphatic polyaminopolycarboxylic acids

PH adjusted PAGE

Hydroxy buffers incorporated within the gel

49. Which of the following statements is NOT true with respect to homogeneous methods:

All homogeneous immunoassays are one-site

All homogeneous immunoassays are competitive

All homogeneous immunoassays are fast assays

All homogeneous immunoassays are non-competitve

50. In SDS PAGE electrophoresis, which of the following statements is NOT TRUE:

The proteins have the same charge-to-mass ratio

The proteins are separated based on their size alone

SDS carries a negative charge

The proteins are separated based on their charge

51. The function of the label is:

To distinguish between the free and bound antigens

A means in which the free antigens or Antigen-Antibody complexes can be detected

To be always in excess to increase signal to noise ratio (S/N)

All of the above

52. The calibration curve (response) in FPIA methods:

Increase with increasing antigen concentration

Decrease with increasing antigen concentration

Increase with increasing antibody concentration

Decrease with increasing antibody concentration

53. The term "ligand" in ligand assay refers to the:

Radionnuclide used in the procedure

Substance being quantitied

Bound complex being formed in the reaction

Standard used to calibrate the method

54. The advantage of polyacrylamide gel versus agarose is:

The range of pore sizes possible is much broader

Possible to load larger quantities of material

Polyacrylamide forms gels with pores that have a much more controlled and uniform size than does agarose

All of the above

55. Which of the following statements is NOT true in FPIA assays? The fluorescence intensity:

Of the free tracer-analyte decreases as the molecule rotates

Is directly proportional to the bound fraction of the tracer-analyte

Is increased at high concentrations of antigen

56. Which of the following is a chemiluminescent label:

Alkaline phosphatase

Ruthenium

Floroescein isothyocyanate

Acridium esters with H2O2

57. In a competitive heterogeneous immunoassay of Ag's in a serum sample, the response will:

Decrease with the level of antibodies in the serum

Increase with the level of antibodies in the serum

Not change with the level of antibodies in the serum

Is dependent only on the concentration of labeled antibodies

58. In a two step sequential immunoassay, the first step involves the:

Addition of antigen-label in excess

Addition of excess antibody

Addition of patient antigen

Addition of both patient and labeled antigens

59. Increasing the ionic strength of the buffer used in the electrophoretic separation of proteins would result in which of the following:

Decreased migration of proteins

Increased build up of heat

Decreased band resolution

Increased migration of proteins

60. In a sandwich assay the concentration of a specific antigen present in a serum sample,

All of the above.

61. A student made up the electrophoresis buffer at pH 6.8 instead of 8.6. Which of the following statements best reflects the impact?

Proteins would be negatively charged and migrate towards the cathode

Proteins would be positively charged and migrate towards the anode

No migration would occur

Proteins would be postively charged and migrate towards the cathode

62. Kosmotropic agents:

Promote destabilization of protein aggregates

Promote aggregation of hydrophobic solutes

Denature proteins

Precipitate proteins in stable structure

63. In homogeneous enzyme immunoassays (EIA) represented by the reaction illustrated below, which of the following statements is true: Ag-Enzyme + Ab + Ag ------------------> Ag:Ab:Ag-Enzyme

The antigen is in excess and the decrease in enzyme activity is directly proportional to Ag concentration

The Ab is in excess and the increase in enzyme activity is directly proportional to the Ag concentration

The Ab-Enzyme is in excess and the decrease in enzyme activity is directly proportional to the Ag concentration

The Ab-Enzyme is in excess and the increase in enzyme activity is directly proportional to Ag concentration

64. Sort the following analytical techniques from lowest to highest sensitivty:

1

2

3

4

Submit

Chemistry Quiz 3

1. If the viscosity of the support medium used in a protein electrophoresis system is too high (thick), the migration rate will

2.

What first name or nickname would you like us to use?

2. The isoelectric point (pI) of a protein is the pH at which:

3. SDS Page electrophoresis is used to:

4. An epitope is:

5. Antigen-Antibody complexes can be dissociated by ______________________

6. Analytical Procedures that use enzymes as reagents add the enzymes in excess to ensure completion of reaction in a short time period

7. In an electrophoresis system, the __________ is the negative electrode.

8. The advantage of enzyme immunoassays over fluorescent immunoassays is that enzyme immunoassays:

9. In electrophoresis, the mobility of the serum proteins is increased when the:

10. Binding of Antigens to Antibodies does not involve which of the following bonds:

11. Binding of antigens to antibodies does not involve which of the following bonds:

12. Which one of the following separation techniques could be used instead if you were looking to separate molecules based on molecular weight?

13. You set up a morning protein electrophoresis run and are going for a coffee break. You return 45 mins later, you stain the gel and notice that the bands did not migrate very far from the point of application. What is the likely explanation?

14. In electrophoresis - the function of the buffer is to:

15. 2D-Immunoelectrophoresis electrophoresis is a technique in which antigens are separated by:

17. In antigen (Ag) antibody (Ab) reactions, the Ag-Ab complex precipitation occurs:

18. Heat generated in an electrophoretic unit is equal to ?

19. Which of the following statements best defines Luminescence?

20. If an electrophoretic buffer were diluted before use instead of using it at normal strength, how would electrophoresis be affected?

21. Which of the following is NOT a homogeneous method:

22. Which of the following statements is/are true with respect to proteins?

23. Which of the following is a fluorescent label?

24. In a sandwich technique for a specific antigen:

25. Affinity is defined as the:

26. Isoelectric focusing proteins:

27. The term avidity is used to designate:

28. How does the net charge of the proteins in a sample affect the electrophoretic mobility of protein fractions?

29. In affinity chromatography, proteins are separated:

30. Another way that bias can be defined is as ________ error.

31. In a competitive heterogeneous immunoassay of Ag's in a serum sample:

32. In a sandwich assay of the concentration of a specific antigen present in a serum sample, the response will:

33. In SDS PAGE electrophoresis, which of the following statements is true:

34. What is the importance of the ionic strength of the buffer used in gel electrophoresis?

35. The rate of rotation of molecules in a liquid at a constant temperature is:

36. Antigen-antibody complexes can be dissociated by:

37. Which of the following immunoassay techniques utilizes genetically engineered enzyme fragments in the assay design:

38. Immunofixation electrophoresis:

39. At high concentrations, added salt:

40. Isoelectric focusing is a technique in which proteins are separated:

41. In SDS-PAGE electrophoresis every protein _________ which will cause all proteins to migrate towards the cathode with a rate ______________.

42. In competitive heterogeneous methods:

43. Which of the following statements is NOT true with respect to chemiluminescence:

44. Which of the following is not correct with regards to fluorescent immunoassays?

45. In size exclusion chromatography, the larger molecules

46. The calibration curve (response) in EMIT methods:

47. At a pH of 4.0, the

48. In isoelectric focusing, the gel within the column consists of:

49. Which of the following statements is NOT true with respect to homogeneous methods:

50. In SDS PAGE electrophoresis, which of the following statements is NOT TRUE:

51. The function of the label is:

52. The calibration curve (response) in FPIA methods:

53. The term "ligand" in ligand assay refers to the:

54. The advantage of polyacrylamide gel versus agarose is:

55. Which of the following statements is NOT true in FPIA assays? The fluorescence intensity:

56. Which of the following is a chemiluminescent label:

57. In a competitive heterogeneous immunoassay of Ag's in a serum sample, the response will:

58. In a two step sequential immunoassay, the first step involves the:

59. Increasing the ionic strength of the buffer used in the electrophoretic separation of proteins would result in which of the following:

60. In a sandwich assay the concentration of a specific antigen present in a serum sample,

61. A student made up the electrophoresis buffer at pH 6.8 instead of 8.6. Which of the following statements best reflects the impact?

62. Kosmotropic agents:

63. In homogeneous enzyme immunoassays (EIA) represented by the reaction illustrated below, which of the following statements is true: Ag-Enzyme + Ab + Ag ------------------> Ag:Ab:Ag-Enzyme

64. Sort the following analytical techniques from lowest to highest sensitivty:

41. In SDS-PAGE electrophoresis every protein _ which will cause all proteins to migrate towards the cathode with a rate ______.