1. In ___________ treatment, certain molecules interact through ionic or Vander wall forces which leads to solubilization of phospholipids and lipoprotein which in turn, increases membrane permeability directing to cell lysis.
a) Lysozyme
b) EDTA
c) Detergent
d) NaoH
Explanation: In detergent treatment, Cell lysis is performed by increasing membrane permeability by solubilizing phospholipids and lipoproteins present in the cell wall. This is done through interaction if detergents through ionic or Vander wall forces. In lysozyme treatment, lysozymes act by catalyzing the β (1 → 4) glycosidic linkages of NAM and NAG present in the cell wall. EDTA acts as a divalent chelator and chelate ions present in the cell wall. NaOH is an alkali and act by having a nucleophilic attack on the cell wall or cell membrane.
2. Which of the following is cationic detergent?
a) Sodium dodecyl sulphate (SDS)
b) Cetyl triethyl ammonium bromide
c) Sodium lauryl sulphate (SLS)
d) Triton-X-100
Explanation: In detergent treatment, 2 types of detergent are used namely, ionic and non-ionic. Ionic also has 2 types: cationic and anionic detergents. SDS and SLS and anionic detergents as compared to triton-X-100 which is a non-ionic detergent. Cetyl trimethyl ammonium bromide is a cationic detergent.
3. __________________ is an example of anionic detergent.
a) Tween
b) Cetyl triethyl ammonium bromide
c) Sodium dodecyl sulphate (SDS)
d) Triton-X-100
Explanation: SDS is an anionic detergent as compared to tween and triton-X-100 which are examples of non-ionic detergents. Cetyl triethyl ammonium bromide is an example for cationic detergents. Sodium lauryl sulphate is also an example for anionic detergents.
4. The techniques which adopts the hypertonic and hypotonic condition for cell lysis is referred to as ____________
a) EDTA treatment
b) Ultrasonification
c) Osmotic shock
d) Homogenization
Explanation: Osmotic shock is a technique which utilizes the hypertonic and hypotonic condition for cell lysis. In hypertonic condition, water molecules move out due to osmosis and shrink the cell. Whereas in the hypotonic condition, the water molecules enter the cell, bulging the cytosol and finally bursting of cell to remove the cell content outside. 1.4 % buffered sucrose is used for this purpose. Ultrasonification and homogenization are methods to extract enzymes by physical methods. EDTA acts as a chelating agent and thus extract enzymes by chemical methods.
5. Which of the following is not a physical method for extraction of enzymes?
a) Osmotic shock
b) Ultrasonication
c) Homogenization
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.
6. ____________ is a phenomenon of assuming frequencies more than 20 kHz which is above the human audibility.
a) Homogenization
b) Ultrasonics
c) Alkali treatment
d) Freezing
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.
7. 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
c) ultrasonication
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.
8. Homogenization cannot be done by using which one of the following?
a) Homogenizer
b) Mortar and pestle
c) French press
d) Ultrasonicator
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.
9. Homogenization utilizing ____________ is one where in manual pressure is created for cell lysis.
a) mortar and pestle
b) ultrasonicator
c) freezer
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.
10. 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.
a) ultrasonicator
b) homogenizer
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.