Mastering SDS-PAGE Gel Preparation

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Which scientist first observed the phenomenon of electrophoresis?

Albert Einstein
Marie Curie
Ferdinand Frederic Reuss (correct)
Isaac Newton

What determines the speed of movement during electrophoresis?

Volume of the fluid
Temperature of the fluid
Magnitude of the charge (correct)
Color of the particles

Which biopolymers can be separated and quantitated by electrophoretic methods?

Proteins and nucleic acids (correct)
Enzymes and hormones
Lipids and carbohydrates
Vitamins and minerals

What is the main application of electrophoresis?

Fundamental research and diagnostics (A) Signup and view all the answers

Which type of gel is commonly used for proteins?

Polyacrylamide gels (B) Signup and view all the answers

What is the range of separation for DNA fragments in agarose gels?

50-20,000 bp (C) Signup and view all the answers

What is the most common gel media used today?

Agarose (A) Signup and view all the answers

What is the purpose of the DNA loading dye in agarose gel electrophoresis?

To visualize DNA migration (A) Signup and view all the answers

Which of the following statements about ethidium bromide (EtBr) is true?

EtBr is a mutagen (B) Signup and view all the answers

Which buffer is commonly used for routine DNA agarose gel electrophoresis?

TAE Buffer (B) Signup and view all the answers

What is the purpose of pulsing the electric field in pulsed-field gel electrophoresis (PFGE)?

To separate large DNA fragments (D) Signup and view all the answers

What is the separation principle of SDS-PAGE based on?

Difference in protein size (B) Signup and view all the answers

Which ions are present at a higher concentration in the double layer near the wall?

Counterions (A) Signup and view all the answers

What is the overall solvent movement called when counterions migrate towards the cathode under an electric field?

Electroosmotic flow (A) Signup and view all the answers

How can the electroosmotic flow be controlled?

By using organic solvents (D) Signup and view all the answers

What is the apparent mobility in electrophoretic separation determined by?

Both the electrophoretic and electroosmotic mobility (C) Signup and view all the answers

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 (C) Signup and view all the answers

What are the units of electrophoretic mobility?

m^2 V^-1 s^-1 (C) Signup and view all the answers

What is the principle behind electrophoretic separations in a gel?

Differences in mobility and the sieving effect of the gel (C) Signup and view all the answers

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 (D) Signup and view all the answers

Which of the following is true about SDS-PAGE gel preparation?

Ammonium persulfate is added last in the reaction mix (B) Signup and view all the answers

Why are there two layers of gel in SDS-PAGE?

To accurately size fractionate proteins (B) Signup and view all the answers

What is the purpose of Coomassie Blue staining in SDS-PAGE?

To visualize proteins as blue bands (B) Signup and view all the answers

What is the most sensitive method for detecting total protein in SDS-PAGE?

Silver staining (C) Signup and view all the answers

Which chemicals can cause chemical crosslinking of proteins in the gel matrix, limiting compatibility with downstream analysis by mass spectrometry?

Both glutaraldehyde and formaldehyde (C) Signup and view all the answers

What is the isoelectric point (pI) of an amino acid?

The pH where the amino acid exhibits no net charge (C) Signup and view all the answers

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 (B) Signup and view all the answers

What happens to an amino acid at its isoelectric point under an applied electric field?

The amino acid remains stationary (C) Signup and view all the answers

What is the purpose of creating a pH gradient in the gel in isoelectric focusing?

To create a stable pH gradient with constant conductivity (D) Signup and view all the answers

What are carrier ampholytes?

Molecules that can react both as an acid and a base (C) Signup and view all the answers