Chemistry Quiz 3
.
- 1.
Another way that bias can be defined is as ________ error.
- A.
Random
- B.
Systematic
- C.
Analytical
- D.
Clinical
Correct Answer
B. Systematic -
- 2.
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?
- A.
Ion-exchange
- B.
Partition
- C.
Affinity
- D.
Adsorption
Correct Answer
A. Ion-exchange -
- 3.
Binding of Antigens to Antibodies does not involve which of the following bonds:
- A.
Electrostatic Interactions
- B.
Hydrophobic Interactions
- C.
Hydrogen Bonds
- D.
Covalent Interactions
Correct Answer
D. Covalent Interactions -
- 4.
The isoelectric point (pI) of a protein is the pH at which:
- A.
The protein has no net charge
- B.
The protein has a negative charge
- C.
The protein has a positive charge
- D.
A protein migrates best in electrophoresis
Correct Answer
A. The protein has no net charge -
- 5.
The term "ligand" in ligand assay refers to the:
- A.
Radionnuclide used in the procedure
- B.
Substance being quantitied
- C.
Bound complex being formed in the reaction
- D.
Standard used to calibrate the method
Correct Answer
B. Substance being quantitied -
- 6.
Affinity is defined as the:
- A.
Strength of the reaction between a multi-variant antigenic site and a single antibody combining site
- B.
Strength of the reaction between a single antigenic site and a multi-variant antibody combining site
- C.
Strength of the reaction between a single antigenic site and a single antibody combining site
- D.
Overall strength of binding between a multi-variant antigenic site and a multivalent antibody site.
Correct Answer
C. Strength of the reaction between a single antigenic site and a single antibody combining site -
- 7.
At high concentrations, added salt:
- A.
Increases the solubility of macromolecules
- B.
Decreases the solubility of macromolecules
- C.
Sustains the solvation of the protein
- D.
Prevents aggregation of the protein
Correct Answer
B. Decreases the solubility of macromolecules -
- 8.
Which of the following statements is/are true with respect to proteins?
- A.
Proteins are amphoteric compounds
- B.
Proteins are lipid soluble
- C.
Protein charge is based on pH of the medium
- D.
Only a and b
- E.
Only a and c
Correct Answer
E. Only a and c -
- 9.
In affinity chromatography, proteins are separated:
- A.
By charge
- B.
By size
- C.
By molecular weight
- D.
Binding to a specific ligand
Correct Answer
D. Binding to a specific ligand -
- 10.
Which one of the following separation techniques could be used instead if you were looking to separate molecules based on molecular weight?
- A.
Partition
- B.
Affinity
- C.
Adsorption
- D.
Size Exclusion
Correct Answer
D. Size Exclusion -
- 11.
The calibration curve (response) in FPIA methods:
- A.
Increase with increasing antigen concentration
- B.
Decrease with increasing antigen concentration
- C.
Increase with increasing antibody concentration
- D.
Decrease with increasing antibody concentration
Correct Answer
B. Decrease with increasing antigen concentration -
- 12.
At a pH of 4.0, the
- A.
Carboxyl and amino groups of an amino acid become unprotonated, causing the amino acid to be anionic
- B.
Carboxyl and amino groups of an amino acid become protonated, causing the amino acid to be cationic
- C.
Carboxyl group of an amino acid is dissociated and the amino group is protonated
- D.
Amino group of an amino acid is dissociated and the carboxyl group is protonated
Correct Answer
B. Carboxyl and amino groups of an amino acid become protonated, causing the amino acid to be cationic -
- 13.
Which of the following is a chemiluminescent label:
- A.
Alkaline phosphatase
- B.
Ruthenium
- C.
Floroescein isothyocyanate
- D.
Acridium esters with H2O2
Correct Answer
D. Acridium esters with H2O2 -
- 14.
SDS Page electrophoresis is used to:
- A.
Determine the charge of a protein
- B.
Determine the molecular weight of a protein
- C.
Isolate a protein which is not denatured by process
Correct Answer
B. Determine the molecular weight of a protein -
- 15.
Isoelectric focusing is a technique in which proteins are separated:
- A.
By charge alone
- B.
By size alone
- C.
By pH and charge
- D.
By pH and size
Correct Answer
C. By pH and charge -
- 16.
Which of the following statements best defines Luminescence?
- A.
The emission of light by a substance after absorption of excitation energy
- B.
Emission of light due to nonthermal process, a chemical reaction, or the absorption of ionizing radiation
- C.
This light is absorbed by the ground state atoms
- D.
Emission of light requiring a light source
Correct Answer
B. Emission of light due to nonthermal process, a chemical reaction, or the absorption of ionizing radiation -
- 17.
The advantage of polyacrylamide gel versus agarose is:
- A.
The range of pore sizes possible is much broader
- B.
Possible to load larger quantities of material
- C.
Polyacrylamide forms gels with pores that have a much more controlled and uniform size than does agarose
- D.
All of the above
Correct Answer
C. Polyacrylamide forms gels with pores that have a much more controlled and uniform size than does agarose -
- 18.
Kosmotropic agents:
- A.
Promote destabilization of protein aggregates
- B.
Promote aggregation of hydrophobic solutes
- C.
Denature proteins
- D.
Precipitate proteins in stable structure
Correct Answer
D. Precipitate proteins in stable structure -
- 19.
Which of the following is a fluorescent label?
- A.
Alkaline Phosphatase
- B.
Ruthenium
- C.
Fluoroescein Isothyocyanate
- D.
Acridium Esters with H2O2
Correct Answer
C. Fluoroescein Isothyocyanate -
- 20.
Increasing the ionic strength of the buffer used in the electrophoretic separation of proteins would result in which of the following:
- A.
Decreased migration of proteins
- B.
Increased build up of heat
- C.
Decreased band resolution
- D.
Increased migration of proteins
Correct Answer
B. Increased build up of heat -
- 21.
In competitive heterogeneous methods:
- A.
The antibody is in excess
- B.
The antigen is in excess
- C.
Involves secondary labeled antibody
- D.
ELISA is the prototype
Correct Answer
B. The antigen is in excess -
- 22.
In SDS PAGE electrophoresis, which of the following statements is true:
- A.
The proteins are separated based on their charge-to-mass ratio
- B.
SDS carries a positive charge
- C.
The proteins are separated based on their size alone
- D.
The proteins are separated based on their charge alone
Correct Answer
C. The proteins are separated based on their size alone -
- 23.
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.
A chemical reaction occurred between the buffer and all samples
- B.
The current or voltage on the power supply was set too low
- C.
Too much sample was applied to the gel
- D.
The electrophoresis chamber was not connected to a power supply
Correct Answer
B. The current or voltage on the power supply was set too low -
- 24.
A student made up the electrophoresis buffer at pH 6.8 instead of 8.6. Which of the following statements best reflects the impact?
- A.
Proteins would be negatively charged and migrate towards the cathode
- B.
Proteins would be positively charged and migrate towards the anode
- C.
No migration would occur
- D.
Proteins would be postively charged and migrate towards the cathode
Correct Answer
D. Proteins would be postively charged and migrate towards the cathode -
- 25.
The term avidity is used to designate:
- A.
The strength of binding of a multivalent antigen with antibody
- B.
Strength of binding between the antibody and the multivalent antigen
- C.
Analytical sensitivity of the assay
- D.
Analytical specificity of assay
Correct Answer
B. Strength of binding between the antibody and the multivalent antigen -
- 26.
In electrophoresis - the function of the buffer is to:
- A.
Carry the applied current
- B.
Establish charge of the solute
- C.
Both a and b
- D.
Maintain the stability of the agarose gel
Correct Answer
C. Both a and b -
- 27.
Which of the following statements is NOT true with respect to homogeneous methods:
- A.
All homogeneous immunoassays are one-site
- B.
All homogeneous immunoassays are competitive
- C.
All homogeneous immunoassays are fast assays
- D.
All homogeneous immunoassays are non-competitve
Correct Answer
D. All homogeneous immunoassays are non-competitve -
- 28.
In electrophoresis, the mobility of the serum proteins is increased when the:
- A.
Current is decreased
- B.
Ionic strength of the buffer is decreased
- C.
Current is increased
- D.
Voltage is decreased
Correct Answer
C. Current is increased -
- 29.
Which of the following immunoassay techniques utilizes genetically engineered enzyme fragments in the assay design:
- A.
EMIT
- B.
CEDIA
- C.
ELISA
- D.
FPIA
Correct Answer
B. CEDIA -
- 30.
The rate of rotation of molecules in a liquid at a constant temperature is:
- A.
Directly proportional to size
- B.
Inversely proportional to size
- C.
Directly proportional to rate of diffusion
Correct Answer
B. Inversely proportional to size -
- 31.
2D-Immunoelectrophoresis electrophoresis is a technique in which antigens are separated by:
- A.
By charge alone
- B.
By size alone
- C.
By size and isoelectric point
- D.
Isoelectric point alone
Correct Answer
C. By size and isoelectric point -
- 32.
How does the net charge of the proteins in a sample affect the electrophoretic mobility of protein fractions?
- A.
It is inversely proportional to electrophoretic mobility
- B.
It is directly proportional to electrophoretic mobility
- C.
It is equal to the electrophoretic mobility
- D.
There is no relationship between net charge and electrophoretic mobility
Correct Answer
B. It is directly proportional to electrophoretic mobility -
- 33.
Antigen-antibody complexes can be dissociated by:
- A.
High pH
- B.
High salt concentrations
- C.
Low pH
- D.
All of the above
Correct Answer
D. All of the above -
- 34.
In antigen (Ag) antibody (Ab) reactions, the Ag-Ab complex precipitation occurs:
- A.
Decreasing concentration of Ag
- B.
At the Ag-Ab equivalence point
- C.
Increasing concentration of Ag
- D.
Decreasing concentration of Ab
Correct Answer
B. At the Ag-Ab equivalence point -
- 35.
The calibration curve (response) in EMIT methods:
- A.
Decrease with increasing antigen concentration
- B.
Increase with increasing antigen concentration
- C.
Increase with increasing antibody concentration
- D.
Decrease with increasing antibody concentration
Correct Answer
B. Increase with increasing antigen concentration -
- 36.
Which of the following is NOT a homogeneous method:
- A.
EMIT
- B.
FPIA
- C.
ELISA
- D.
CEDIA
Correct Answer
C. ELISA -
- 37.
Which of the following statements is NOT true in FPIA assays? The fluorescence intensity:
- A.
Of the free tracer-analyte decreases as the molecule rotates
- B.
Is directly proportional to the bound fraction of the tracer-analyte
- C.
Is increased at high concentrations of antigen
Correct Answer
C. Is increased at high concentrations of antigen -
- 38.
In SDS PAGE electrophoresis, which of the following statements is NOT TRUE:
- A.
The proteins have the same charge-to-mass ratio
- B.
The proteins are separated based on their size alone
- C.
SDS carries a negative charge
- D.
The proteins are separated based on their charge
Correct Answer
D. The proteins are separated based on their charge -
- 39.
In a sandwich technique for a specific antigen:
- A.
The antigen must have one epitope
- B.
The antigen must have more than one epitope
- C.
The antigen must not have an epitope
- D.
The antigen must not bind to the secondary antibody
Correct Answer
B. The antigen must have more than one epitope -
- 40.
Which of the following is not correct with regards to fluorescent immunoassays?
- A.
Uses fluorochromes such as FITC
- B.
Involves the conjugation of fluorochromes to antibodies or antigens
- C.
Uses enzyme linked antibodies of antigens
- D.
Method requires use of a fluorescence detector
Correct Answer
C. Uses enzyme linked antibodies of antigens -
- 41.
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
- A.
The antigen is in excess and the decrease in enzyme activity is directly proportional to Ag concentration
- B.
The Ab is in excess and the increase in enzyme activity is directly proportional to the Ag concentration
- C.
The Ab-Enzyme is in excess and the decrease in enzyme activity is directly proportional to the Ag concentration
- D.
The Ab-Enzyme is in excess and the increase in enzyme activity is directly proportional to Ag concentration
Correct Answer
D. The Ab-Enzyme is in excess and the increase in enzyme activity is directly proportional to Ag concentration -
- 42.
The function of the label is:
- A.
To distinguish between the free and bound antigens
- B.
A means in which the free antigens or Antigen-Antibody complexes can be detected
- C.
To be always in excess to increase signal to noise ratio (S/N)
- D.
All of the above
Correct Answer
B. A means in which the free antigens or Antigen-Antibody complexes can be detected -
- 43.
If the viscosity of the support medium used in a protein electrophoresis system is too high (thick), the migration rate will
- A.
Increase
- B.
Decrease
- C.
Not be affected
Correct Answer
B. Decrease -
- 44.
Heat generated in an electrophoretic unit is equal to ?
- A.
Voltage x Current x Time
- B.
Voltage x Current / Time
- C.
Current x Time
- D.
Voltage x Time
Correct Answer
A. Voltage x Current x Time -
- 45.
Isoelectric focusing proteins:
- A.
Precipitate out of solution when pH of gradient is above the protein pI
- B.
Precipitate out of solution when pH of gradient is below the protein pI
- C.
Precipitate out of solution when pH of gradient is the same as the protein pI
- D.
Precipitate out of solution when fixative buffer is added
Correct Answer
C. Precipitate out of solution when pH of gradient is the same as the protein pI -
- 46.
If an electrophoretic buffer were diluted before use instead of using it at normal strength, how would electrophoresis be affected?
- A.
Increased migration rate of protein
- B.
Decreased migration rate of protein
- C.
No change in the rate of migration of protein
Correct Answer
B. Decreased migration rate of protein -
- 47.
In an electrophoresis system, the __________ is the negative electrode.
- A.
Anode
- B.
Optode
- C.
Cathode
- D.
Diode
Correct Answer
C. Cathode -
- 48.
In a two step sequential immunoassay, the first step involves the:
- A.
Addition of antigen-label in excess
- B.
Addition of excess antibody
- C.
Addition of patient antigen
- D.
Addition of both patient and labeled antigens
Correct Answer
C. Addition of patient antigen -
- 49.
The advantage of enzyme immunoassays over fluorescent immunoassays is that enzyme immunoassays:
- A.
Can be more sensitive due to the conversion of multiple substrate molecules to a multiple product molecules
- B.
Do not require antibodies
- C.
Do not require antigens
- D.
Do not require the use of an antibody-antigen reaction
Correct Answer
A. Can be more sensitive due to the conversion of multiple substrate molecules to a multiple product molecules -
- 50.
In a competitive heterogeneous immunoassay of Ag's in a serum sample:
- A.
A known concentration of unlabeled Ag's is added together with serum to a solid phase onto which antibodies have been bound
- B.
A known concentration of labeled Ag's is added together with serum to a solid phase onto which antibodies have been bound
- C.
An unknown concentration of unlabeled Ab's are added together with serum to a solid phase onto which antibodies have been bound
- D.
An unknown concentration of unlabeled Ab's are added together with serum to a solid phase onto which antigens have been bound
Correct Answer
B. A known concentration of labeled Ag's is added together with serum to a solid phase onto which antibodies have been bound -
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Dec 24, 2020Quiz Edited by
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Apr 23, 2012Quiz Created by
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