250+ TOP MCQs on Extraction of Enzymes by Chemical Methods – 2 and Answers

Enzyme Technology Questions and Answers for Experienced peopleon “Extraction of Enzymes by Chemical Methods – 2”.

1. Extraction of enzymes by physical methods include the usage of alkalis, EDTA, lysozyme, etc.
A. True
B. False
Answer: B
Clarification: Alkalis, EDTA, lysozymes, etc., are chemicals used to extract enzymes from a given source. Hence they fall into extraction of enzymes by chemical methods. Physical methods used to extract enzymes are ultrasonification, homogenization, etc.

2. Alkali treatment is not advisable for which of the following?
A. Extracellular enzymes
B. Bacterial enzymes in cell wall
C. Enzymes in cell wall of plant sources
D. Membrane bound enzymes in eukaryotic cell
Answer: A
Clarification: Alkali treatment is used extracting enzymes from bacterial and plant cell wall. It is also useful in extracting membrane bound enzymes in eukaryotic cell. But extracellular enzymes are difficult to extract from this method. Hence it is not advisable to use alkali treatment for extraction of extracellular enzymes.

3. The enzyme which specifically catalyzes β (1 → 4) glycosidic linkages of NAM (N-acetyl muramic aciD. and NAG (N-acetyl glucosamine) present in bacterial peptidoglycan is _______________
A. protease
B. lipase
C. lysozyme
D. cellulase
Answer: C
Clarification: Lysozyme is an enzyme which catalyzes the β (1 → 4) glycosidic linkages of NAM (N-acetyl muramic aciD. and NAG (N-acetyl glucosamine) present in bacterial peptidoglycan. Proteases catalyzes the breakdown of proteins into smaller peptides or single amino acids. Lipase catalyzes the hydrolysis of fats. Cellulase catalyzes the breakdown of cellulose and other polysaccharides to monosaccharides.

4. ___________ is a divalent chelator which can be used to extract enzymes from different sources.
A. Sucrose
B. NaOH
C. Lysozyme
D. EDTA
Answer: D
Clarification: EDTA is a divalent chelator which chelate the metal ions such as Mg²⁺ and Ca²⁺ which are important for cell wall stability. There is an electrostatic interaction between highly electropositive and electronegative compounds which provide gently cell lysis. EDTA along with some other efficient agents can help in proper n complete cell lysis.

5. Which one of the following is not an example for ionic-detergent?
A. Sodium dodecyl sulphate (SDS)
B. Tween
C. Sodium lauryl sulphate (SLS)
D. Cetyl trimethyl ammonium bromide
Answer: B
Clarification: In detergent treatment, 2 types of detergent are used namely, ionic and non-ionic. Tween and triton-X-100 are examples of non-ionic detergents as compared to SDS, SLS and cetyl trimethyl ammonium bromide are examples of ionic detergent.

6. Pick odd one out.
A. Triton-X-100
B. Cetyl triethyl ammonium bromide
C. Sodium lauryl sulphate (SLS)
D. Cetyl trimethyl ammonium bromide
Answer: A
Clarification: Triton-X-100 is odd one out as SDS, SLS and cetyl trimethyl ammonium bromide are examples for ionic detergents as compared to triton-X-100 which is non-ionic detergent.

7. The phenomenon wherein the osmotic pressure created due to presence of solutes inside and outside the cells will be equal is referred to as ________
A. isotonic condition
B. hypertonic condition
C. hypotonic condition
D. osmotic shock
Answer: A
Clarification: Isotonic condition is the phenomenon wherein the osmotic pressure created due to presence of solutes inside and outside the cell will be equal. In hypertonic condition, the water molecules will move out due to osmosis and the cell cytosol will shrink. In case of hypotonic condition, the water molecules from outside will move inside the cell which leads to bulging of cytosol and then bursting. Osmotic shock is technique which uses these two above conditions to extract enzymes from cells.

8. Which chemical is used for extracting enzymes by osmotic shock treatment?
A. EDTA
B. NaoH
C. SDS
D. 1.4% buffered sucrose
Answer: D
Clarification: 1.4% buffered sucrose is used to extract enzyme by osmotic method. Washing the cells and equilibrating with this solution leads to bursting and releasing the content outside. Centrifugation is then performed to remove cell debris and extract enzymes separately. EDTA acts as chelating agent which chelate ions present in the cell wall. NaOH is an alkali and acts by nucleophilic attack. SDS is an anionic detergent that solubilizes the phospholipids and lipoproteins present in the cell wall.

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