Question 1
____________ are materials that absorb selected molecular compounds and catalyze chemical reactions.
A. Catalysts
B. Chromium
C. Zeolite
D. None of the mentioned
View Answer
Question 2
____________ in EGR results in some cycle partial burns and, in the extreme, total misfires.
A. Decrease
B. Increase
C. Consistency
D. None of the mentioned
View Answer
Question 3
____________ is collected during engine startup time when the catalytic converter is cold, and then later released back into the exhaust flow when the converter is hot.
A. HC
B. CO
C. CO2
D. H2O
View Answer
Question 4
Cyanuric acid is a ____________ solid material that sublimes in the exhaust flow.
A. high-cost
B. low-cost
C. unpredictable
D. none of the mentioned
View Answer
Question 5
EGR combines with the exhaust residual left in the cylinder from the previous cycle to effectively reduce the ____________ combustion temperature.
A. minimum
B. maximum
C. unpredictable
D. none of the mentioned
View Answer
Question 6
Exhaust gas recycle is done by ducting some of the exhaust flow back into the intake system.
A. TRUE
B. FALSE
View Answer
Question 7
H2 emissions occur under ____________ operating conditions.
A. rich
B. lean
C. constant
D. none of the mentioned
View Answer
Question 8
The amount of flow in EGR, can be as high as ____________ of the total intake.
A. 20%
B. 30%
C. 35%
D. 40%
View Answer
Question 9
The flow rate of EGR is not controlled by the Engine management system.
A. TRUE
B. FALSE
View Answer
Question 10
____________ is an enzyme, which is highly produced by egg white and lachrymal glands.
A. Amylases
B. Lysozyme
C. Invertase
D. Protease
View Answer
Answer: Option B
Explanation:
Lysozyme is produced by egg white and lachrymal glands. Amylases is produced by malted barley, bacillus species, aspergillus species etc. Invertase is produced from saccharomyces species and protease from aspergillus and bacillus species.
Question 11
__________________ is an example of anionic detergent.
A. Tween
B. Cetyl triethyl ammonium bromide
C. Sodium dodecyl sulphate (SDS)
D. Triton-X-100
View Answer
Answer: Option C
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.
Question 12
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
View Answer
Answer: Option A
Explanation:
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.
Question 13
Extraction of enzymes by physical methods include the usage of alkalis, EDTA, lysozyme, etc.
A. True
B. False
View Answer
Answer: Option B
Explanation:
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.
Question 14
Gram positive bacteria are highly susceptible to lysozyme treatment.
A. True
B. False
View Answer
Answer: Option A
Explanation:
Lysozyme catalyzes the β (1 → 4) glycosidic linkages of NAM (N-acetyl muramic acid) and NAG (N-acetyl glucosamine) present in bacterial peptidoglycan. Peptidoglycan content in high in gram positive bacteria as compared to gram negative bacteria. Hence gram positive bacteria are highly susceptible lysozyme treatment.
Question 15
In ________ treatment, produced basic radicals mediate a nucleophilic attack on compounds of cell wall on membrane leading to destabilization and fragmentation of membrane followed by release of enzymes.
A. EDTA
B. Osmotic shock
C. Alkali
D. Detergent
View Answer
Answer: Option C
Explanation:
In alkali treatment, Alkalis produce basic radical which mediate a nucleophilic attack on compounds of cell wall or cell membrane which leads to destabilization of membrane, followed by membrane fragmentation. This allows leakage of cytoplasm which has enzyme of interest. Care has to be taken about alkalinity of the solution as enzyme may get denaturated at high pH.
Question 16
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
View Answer
Answer: Option C
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.
Question 17
Pick odd one out.
A. Triton-X-100
B. Cetyl triethyl ammonium bromide
C. Sodium lauryl sulphate (SLS)
D. Cetyl trimethyl ammonium bromide
View Answer
Answer: Option A
Explanation:
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.
Question 18
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
View Answer
Answer: Option C
Explanation:
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.
Question 19
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
View Answer
Answer: Option A
Explanation:
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.
Question 20
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
View Answer
Answer: Option C
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.
Question 21
Which chemical is used for extracting enzymes by osmotic shock treatment?
A. EDTA
B. NaoH
C. SDS
D. 1.4% buffered sucrose
View Answer
Answer: Option D
Explanation:
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.
Question 22
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
View Answer
Answer: Option B
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.
Question 23
Which of the following is not a technique for the extraction of enzymes by chemical methods?
A. Alkali treatment
B. Osmotic shock
C. Detergent treatment
D. Homogenization
View Answer
Answer: Option D
Explanation:
Homogenization is a method to extract enzymes using physical methods. Chemical methods involve different chemicals like EDTA, lysozymes, NaoH etc. to isolate enzymes from selected sources. Hence alkali treatment, Osmotic shock and Detergent treatment falling into the category extracting enzymes by chemical methods.
Question 24
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
View Answer
Answer: Option B
Explanation:
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.