This set of Enzyme Technology Multiple Choice Questions & Answers (MCQs) focuses on “Extraction of Enzymes by Physical Methods”.
1. Which of the following is not a physical method for extraction of enzymes?
a) Osmotic shock
d) Freezing technique
Explanation: Osmotic shock is a chemical method for extracting enzymes by using 1.4% buffered sucrose. Osmotic shock is a technique which adopts the hypertonic or hypotonic condition for cell lysis. For extracting enzymes, physical methods include ultrasonication, homogenization, freezing technique, etc.
2. ____________ is a phenomenon of assuming frequencies more than 20 kHz which is above the human audibility.
c) Alkali treatment
Explanation: The phenomenon which assumes frequencies more than 20 kHz. This frequency is above human audibility which corresponds to 6.1 to 2.3 *10-4 cm wavelength. Homogenization is a mechanical technique adopted widely to disrupt the cell wall and cell membrane. Freezing is nothing but a cold or psychrophilic shock. Alkali treatment is a chemical method for extraction of enzymes which uses a nucleophilic attack of basic radicals on the cell wall.
3. The procedure in which cell lysis occur because of shock waves which are formed due to collapses occurring in buffered solution containing cells is referred to as _______________
a) alkali treatment
b) osmotic shock
d) detergent treatment
Explanation: When the cells in buffered solution are applied with ultrasonics, areas of compression and rarefaction are created which leads to formation of cavities which in turn collapses that area. This collapse leads to formation of shock waves that mediate cell lysis. This procedure is referred to as Ultrasonication. Detergent treatment, osmotic shock and alkali treatment are the methods which extract enzymes using chemicals.
4. Homogenization cannot be done by using which one of the following?
b) Mortar and pestle
c) French press
Explanation: Homogenization is a mechanical technique widely adopted to disrupt the cell wall or membrane. Homogenizer, mortar and pestle and french press are used for performing homogenization. Ultrasonicator is used for performing ultrasonication.
5. Homogenization utilizing ____________ is one where in manual pressure is created for cell lysis.
a) mortar and pestle
d) french press
Explanation: Traditional method for homogenization utilizes mortar and pestle wherein manual pressure is created by pestle in a mortar for cell lysis. Ultrasonicator is a machine used for ultrasonication. Freezer is refrigerator with temperatures as low as -20° C or -80° C. French press is one which the cell are ruptured by passing through small orifice.
6. A _________ has long teflon tube about 30-40 cm long which is bulged at the end and has an automated machine for providing the pressure.
c) osmotic shock
d) mortar and pestle
Explanation: Mortar and pestle is a traditional homogenization method where manual pressure is applied. As compared to a modern homogenizer wherein automated pressure is applied through a long teflon tube about 30-40 cm long which is bulged at the end. Ultrasonicator is used to perform ultrasonication on cells to perform cell lysis. Osmotic shock is chemical method for cell lysis which utilizes 1.4% buffered sucrose. It applies the technology of hypertonic and hypotonic solution.
7. Homogenization performed by passing the cells at high pressure through narrow orifice which can also cause cell rupture is referred to as _______________
c) mortar and pestle
d) french press
Explanation: French press is one which the cells are forced at high pressure through narrow orifice is referred to as french press. This procedure also causes the cell rupture. Freezer is refrigerator with temperatures as low as -20° C or -80° C. Ultrasonicator uses ultrasonic waves to lyse the cells. Mortar and pestle is a traditional homogenizer.
8. The technique in which the cells are subjected to cold temperature of about -15° C to -25° C is referred to as _____________
d) osmotic shock
Explanation: In freezing technique, the cells are subjected to cold temperature of about -15° C to -25° C for cell lysis. As compared to Ultrasonics, which uses shock waves formed due to collapses to lyse the cells. Homogenization is a mechanical method to lyse the cells. Osmotic shock uses technology of hypertonic and hypotonic solution to break the cells to extract enzymes from them.
9. ____________ technique is nothing but a cold or psychrophilic shock.
d) Alkali treatment
Explanation: Freezing technique is one which cells are subjected to cold temperatures as low as minus degree Celsius. Due to which the cells get a cold or psychrophilic shock which leads to cell lysis. Ultrasonication uses shock waves whereas homogenization uses mechanical pressure to lyse the cells. Alkali treatment is a chemical method to lyse the cells because of nucleophilic attack on cell walls by the basic radicals.
10. Freezing technique is not preferred unless otherwise there is a need.
Explanation: Freezing involves the cells to be subjected to very cold minus degree Celsius temperatures which may lead to formation intra and extra cellular ice crystals damaging the cells. Also, there is chance of protein denaturation. Hence this technique is not preferred unless otherwise there is a need.
11. Mortar and pestle, french press and homogenizer are widely used to lyse the cells by ultrasonication.
Explanation: Mortar and pestle, french press and homogenizer utilizes pressure in different ways may be manually or automated. Hence they are widely used to lyse the cells by homogenization and not ultrasonication. As ultrasonication uses ultrasonic waves to lyse the cells and the machine used is called Ultrasonicator.
12. __________ is a method which is highly used for lab scale procedures than large scale work.
d) Alkali treatment
Explanation: Ultrasonication is a method which uses ultrasonic waves to lyse the cells. Shock waves are formed due to collapses in area of rarefaction. Hence this method is used for lab scale procedures as compared to large scale work. Homogenization is widely used to disrupt the cell wall or cell membrane. Freezing is nothing but cold or psychrophilic shock. Alkali treatment is a chemical method that uses alkali to lyse the cells.
Sanfoundry Global Education & Learning Series – Enzyme Technology.
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