Enzyme Technology Multiple Choice Questions on “Enzymes Purification – Thin Layer Chromatography”.
1. The presence of enzyme in the sample can be detected by _________________
A. gel exclusion chromatography
B. affinity chromatography
C. ion exchange chromatography
D. thin layer chromatography (TLC.
Answer: D
Clarification: Enzyme which have been clarified and concentrated can be detected by thin layer chromatography. Gel exclusion, affinity and ion-exchange chromatography are used for purification of enzymes based on the property of the enzyme.
2. The method which relies on differences in partitioning behavior between a flowing mobile phase and a stationary phase to separate the components in a mixture is referred to as _________________
A. homogenization
B. dialysis
C. chromatography
D. ultrafiltration
Answer: C
Clarification: In chromatography, there is a column which holds the stationary phase and mobile phase carrying the sample pass through it. The components in the sample which partition strongly in the stationary phase spend greater time in the column and get separated from the components which stay in the mobile and pass through the column faster. As the components get eluted, they may be quantified by a detector or collected for further analysis. Homogenization is a physical technique to separate out the cell components into the medium. Dialysis and ultrafiltration are the steps involved in enzyme purification.
3. Which chromatography technique consist of a stationary phase immobilized on a glass plate and an organic solvent acting as a mobile phase?
A. Ion exchange chromatography
B. Affinity chromatography
C. Thin layer chromatography (TLC.
D. Gel exclusion chromatography
Answer: C
Clarification: In TLC, the stationary phase is immobilized on a glass plate and organic solvent act as the mobile phase. The sample dissolved in the solvent is placed on the stationary phase. The solvent mixture moves up by the capillary action and meet the sample mixture. Different compounds travel at different rates due to their solubility and interactions with the stationary phase absorbents. Gel exclusion, affinity and ion-exchange chromatography are used for purification of enzymes based on the property of the enzyme.
4. If the solvent phase in TLC was 80:20 mixture of hexane and ethyl acetate, the polar compounds will not move as much as non-polar compounds.
A. True
B. False
Answer: A
Clarification: When the solvent is 80:20 mixture of hexane and ethyl acetate, the solvent will be mostly nonpolar. This means that the non-polar compounds will move further up the plate. In contrast the polar compounds will not have moved as much as the non-polar compounds. Hence the statement is true.
5. When the solvent phase in TLC is 20:80 mixture of hexane and ethyl acetate, the polar compounds will not move as much as non-polar compounds.
A. True
B. False
Answer: B
Clarification: In TLC, when the mixture 20:80 mixture of hexane and ethyl acetate, the solvent will become mostly polar. This means polar compounds will move further up in the plate as compared to non-polar compounds. Hence the above statement is false.
6. Pick odd one out.
A. Silica gel
B. Alumina
C. Cellophane
D. Cellulose
