QBM Exam Guide| Questions Solved with
Verified Correct Answers | Latest Update
2024-2025
What is most dangerous about multiple cycles of freezing and thawing? - ANSWER Ice crystals
What protein purification technique utilized precipitation? - ANSWER Ammonium sulfate cut
(salting out)
What is a structure forming salt that does not require water? - ANSWER Ammonium
Sulfate protein purification
Ammonium sulfate - ANSWER Protein purification using precipitation. Purify from organs
or cells and purify new proteins. Inexpensive and difficult to acquire large amounts of
protein. Proteins may aggregate and make purification more difficult.
Chromatograms measured at what wavelength? - ANSWER 280nm
Solvent precipitation protein purification - ANSWER saved for DNA, causes denaturing and
harsh
What do you used to try and fix inclusion bodies? - ANSWER inclusion bodies are
misfolded proteins, chaotropic salts will help
, Chaotropic salts? - ANSWER -opposite of structure-forming salts (AS)
- urea and Guanidine-HCL
Use of detergents? - ANSWER -Resolubilized proteins
- Triton X-100 and SDS
- useful in membrane proteins with exposed hydrophobic regions
Dialysis - ANSWER Buffer exchange
Lyophilization - ANSWER -Way to concentrate protein
- dried under vacuum (powder)
Ultrafiltration - ANSWER concentrate protein
Centrifuge and nitrogen pressure
Reverse dialysis - ANSWER put in tubing, surround with PEG or AS
What does EDTA do? - ANSWER Protease inhibitor that Chelates metals to stop protease.
Chemical lysis is better than using a lysozyme? - ANSWER Yes
What does B-ME do? - ANSWER prevents oxidation and breaks disulfide bond in SDS-Page.
Cheaper but not as good as DTT
what does glycerol do? - ANSWER Prevents ice crystals, makes the samples more dense to
makes sure they sink in the wells of SDS-Page
What does sodium azide do? - ANSWER Inhibits bacterial and fungal growth
Verified Correct Answers | Latest Update
2024-2025
What is most dangerous about multiple cycles of freezing and thawing? - ANSWER Ice crystals
What protein purification technique utilized precipitation? - ANSWER Ammonium sulfate cut
(salting out)
What is a structure forming salt that does not require water? - ANSWER Ammonium
Sulfate protein purification
Ammonium sulfate - ANSWER Protein purification using precipitation. Purify from organs
or cells and purify new proteins. Inexpensive and difficult to acquire large amounts of
protein. Proteins may aggregate and make purification more difficult.
Chromatograms measured at what wavelength? - ANSWER 280nm
Solvent precipitation protein purification - ANSWER saved for DNA, causes denaturing and
harsh
What do you used to try and fix inclusion bodies? - ANSWER inclusion bodies are
misfolded proteins, chaotropic salts will help
, Chaotropic salts? - ANSWER -opposite of structure-forming salts (AS)
- urea and Guanidine-HCL
Use of detergents? - ANSWER -Resolubilized proteins
- Triton X-100 and SDS
- useful in membrane proteins with exposed hydrophobic regions
Dialysis - ANSWER Buffer exchange
Lyophilization - ANSWER -Way to concentrate protein
- dried under vacuum (powder)
Ultrafiltration - ANSWER concentrate protein
Centrifuge and nitrogen pressure
Reverse dialysis - ANSWER put in tubing, surround with PEG or AS
What does EDTA do? - ANSWER Protease inhibitor that Chelates metals to stop protease.
Chemical lysis is better than using a lysozyme? - ANSWER Yes
What does B-ME do? - ANSWER prevents oxidation and breaks disulfide bond in SDS-Page.
Cheaper but not as good as DTT
what does glycerol do? - ANSWER Prevents ice crystals, makes the samples more dense to
makes sure they sink in the wells of SDS-Page
What does sodium azide do? - ANSWER Inhibits bacterial and fungal growth
