30 Questions
Which scientist first observed the phenomenon of electrophoresis?
Ferdinand Frederic Reuss
What determines the speed of movement during electrophoresis?
Magnitude of the charge
Which biopolymers can be separated and quantitated by electrophoretic methods?
Proteins and nucleic acids
What is the main application of electrophoresis?
Fundamental research and diagnostics
Which type of gel is commonly used for proteins?
Polyacrylamide gels
What is the range of separation for DNA fragments in agarose gels?
50-20,000 bp
What is the most common gel media used today?
Agarose
What is the purpose of the DNA loading dye in agarose gel electrophoresis?
To visualize DNA migration
Which of the following statements about ethidium bromide (EtBr) is true?
EtBr is a mutagen
Which buffer is commonly used for routine DNA agarose gel electrophoresis?
TAE Buffer
What is the purpose of pulsing the electric field in pulsed-field gel electrophoresis (PFGE)?
To separate large DNA fragments
What is the separation principle of SDS-PAGE based on?
Difference in protein size
Which ions are present at a higher concentration in the double layer near the wall?
Counterions
What is the overall solvent movement called when counterions migrate towards the cathode under an electric field?
Electroosmotic flow
How can the electroosmotic flow be controlled?
By using organic solvents
What is the apparent mobility in electrophoretic separation determined by?
Both the electrophoretic and electroosmotic mobility
Which of the following is the correct definition of electrophoretic mobility?
The ability of charged particles to move through a medium in response to an electric field
What are the units of electrophoretic mobility?
m^2 V^-1 s^-1
What is the principle behind electrophoretic separations in a gel?
Differences in mobility and the sieving effect of the gel
What is the relationship between electrical mobility and the net charge of a particle?
Electrical mobility is directly proportional to the net charge of a particle
Which of the following is true about SDS-PAGE gel preparation?
Ammonium persulfate is added last in the reaction mix
Why are there two layers of gel in SDS-PAGE?
To accurately size fractionate proteins
What is the purpose of Coomassie Blue staining in SDS-PAGE?
To visualize proteins as blue bands
What is the most sensitive method for detecting total protein in SDS-PAGE?
Silver staining
Which chemicals can cause chemical crosslinking of proteins in the gel matrix, limiting compatibility with downstream analysis by mass spectrometry?
Both glutaraldehyde and formaldehyde
What is the isoelectric point (pI) of an amino acid?
The pH where the amino acid exhibits no net charge
What is the general relationship between the isoelectric point (pI) and the charge of a protein?
Basic proteins have a higher pI, while acidic proteins have a lower pI
What happens to an amino acid at its isoelectric point under an applied electric field?
The amino acid remains stationary
What is the purpose of creating a pH gradient in the gel in isoelectric focusing?
To create a stable pH gradient with constant conductivity
What are carrier ampholytes?
Molecules that can react both as an acid and a base
Learn how to prepare a gel for SDS-PAGE demonstration with this informative quiz. Discover the key features of proteins and understand their behavior in an electric field. Explore the components of the reaction mix, including the gel matrix, and enhance your knowledge of gel preparation techniques. Watch the demonstration video to gain practical insights and enhance your understanding of SDS-PAGE.
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