Category: Drug & Pharmaceutical Biotechnology Objective Questions

Pharmaceutical Biotechnology Questions and Answers for Entrance exams on “Production of Antibiotics (Isolation of Fermentation Products)”.

1. What are antibiotics?
a) Nutrient supplements
b) Anti-cancer drugs
c) Anti-microbial drugs
d) Anti-ulcer drugs

Answer: c
Clarification: Antibiotics are metabolites having antimicrobial activity. Therefore, they are widely used for curing of human ailments caused by microbes. The first antibiotic discovered was penicillin by Alexender Fleming.

2. Who discovered the first antibiotic?
a) Alexander Fleming
b) Louis Pasteur
c) Francis Crick
d) Kary Mullis

Answer: a
Clarification: The antibiotic penicillin was discovered by Alexander Fleming in 1929, but its commercial production commenced only during the early 1940s. Fleming was also the first to raise a concern about the potential of bacteria developing resistance due to the exploitation of antibiotics, a problem which poses a major threat to healthcare in this era.

3. How many antibiotics have still been isolated?
a) 5000
b) 2000
c) 7000
d) 3000

Answer: c
Clarification: Although more than 7,000 antibiotic compounds have been isolated till date, only 100 or so are being used to treat human, animal and plant diseases. The first antibiotic discovered was penicillin by Alexender Fleming.

4. Antibiotics are mainly produced by _________
a) Bacteria
b) Algae
c) Fungi
d) Fungi and bacteria

Answer: d
Clarification: Antibiotic compounds can be used either in their natural form or in their semi-synthetic derivatives. The semi synthetic derivatives are produced by isolating the antibiotic nucleus and subjecting it to certain chemical modification. Antibiotics are produced by both fungi and bacteria.

5. How inoculum is prepared in the production of antibiotics?
a) On solid media
b) On liquid media
c) First on solid media than on liquid media
d) On suspension

Answer: c
Clarification: Inoculum development begins on solid media, and then liquid media are used; the media used are specific for inoculum development. Spore suspension is prepared for inoculum. This will be then transferred to the fermenter.

6. Penicillin is active against ____________
a) Gram +ve bacteria
b) Gram-ve bacteria
c) All virus
d) All bacteria

Answer: a
Clarification: First discovered by Alexander Fleming in 1929. Natural penicillin is active against a variety of gram +ve bacteria organisms. They are labile in acids and become inactive when its beta-lactam ring is cleaved by beta-lactamase enzyme.

7. Penicillin inhibits cell wall synthesis.
a) True
b) False

Answer: a
Clarification: Penicillin is an inhibitor of cell wall synthesis. They bind to penicillin-binding protein (PBP) present in the cell. This results in peptidoglycan synthesis, leading to death to cell death.

8. Penicillium chrysogenum produce penicillin.
a) True
b) False

Answer: a
Clarification: Penicillium chrysogenum or P. Notatum (formerly) is a species of fungus. Common in temperate and subtropical regions. It has rarely caused human disease. It is the source of several β-lactam antibiotics, most significantly penicillin. Other secondary metabolites include roquefortine C, Meleagris, etc.

9. What is the precursor of penicillin?
a) Benzylpenicillin
b) Isopenicillin N
c) phenylacetic acid
d) L-α aminoadipic acid

Answer: c
Clarification: Benzylpenicillin (Penicillin G) is a narrow spectrum antibiotic used to treat infections caused by some bacteria. It is a natural penicillin antibiotic administered intravenously or intramuscularly. Penicillin G may also be used in cases such as prophylaxis against susceptible organisms.

10. pH required for the production of penicillin will be ______________
a) 8.0
b) 7.5
c) 6.5
d) 5.0

Answer: c
Clarification: The pH should be has to be between 6.4 and 6.8 during the active production phase of penicillin. All the necessary precursors, ammonia, sugar, carbon dioxide, oxygen is controlled, by thorough monitoring of temperature and pH for optimal antibiotic production.

11. The doubling time of Penicillium notatum is ___________
a) 6 hrs
b) 5 hrs
c) 4 hrs
d) 3 hrs

Answer: a
Clarification: Growth phase is of 40 hrs duration with a doubling time of 6 hrs. Oxygen supply becomes critical during this phase due to an increase in viscosity of the medium. Production phase duration is 120 to 180 hrs.

12. How is penicillin stored?
a) Filtration
b) Crystallization
c) Distillation
d) Sublimation

Answer: b
Clarification: Pure metal salts of penicillin can be safely sterilized by dry heat if desired. Thereafter, the aqueous solution of penicillin is subjected to crystallization. The alkali metal salts of penicillin are extremely soluble in water, and methods therefore known for crystallizing them have employed organic solvents under nearly anhydrous conditions.

13. Streptomycin is _____ antibiotic.
a) Narrow spectrum
b) Broad spectrum
c) Narrow and broad spectrum
d) Medium spectrum

Answer: b
Clarification: Streptomycin has amino cyclohexanol moiety. It is effective against gram –ve organisms but yet it is broad-spectrum antibiotic. It is used for the treatment of tuberculosis. Its side effect is nephrotoxicity.

14. How is streptomycin recovered?
a) Paper chromatography
b) Hydrophobic chromatography
c) Size exclusion chromatography
d) Ion exchange chromatography

Answer: d
Clarification: Streptomycin is an antibiotic which is used to treat a number of bacterial infections. It is an extracellular product so they are removed by adsorption to ion exchange columns in chromatography. The period of operation is short and streptomycin sulfate is obtained in a single fraction with an overall yield of approximately 60 percent at a purity of 400 to 600 units per mg.

15. pH range required for streptomycin production is __________
a) 7-8
b) 5-8
c) 4-5
d) 9-10

Answer: a
Clarification: The optimum temperature for fermentation should be in the range of 25 to 30°C. The optimum pH range should be in the range of 7.0 and 8.0. High rate of streptomycin production occurs in the pH range of 7.6 to 8.0.

Drug Biotechnology Multiple Choice Questions on “Biopharmaceuticals – Oral Controlled Release Systems”.

1. Oral controlled release drugs release the drug only inside the intestine.
a) True
b) False

Answer: b
Clarification: Continuous release systems release the drug for a prolonged period of time. The drug will be releasing components along the whole length of the GIT with normal transit of the dosage form. It releases the drug especially up to the terminal region of the small intestine.

2. What are the characteristics of continuous release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva

Answer: b
Clarification: Continuous releasing system prolong the residence time of the drug in the GIT of the patient. Thus it gives prolong the period for the drug to dissolve slowly. This type of system can increase the therapeutic time and thus the dosage will be reduced.

3. What is the characteristic of delayed transit and continuous release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva

Answer: b
Clarification: Delayed transit and continuous release systems are designed to prolong their residence in the GIT along with the increase of releasing time. Most of the time the dosage form is fabricated to retain in the stomach and hence the drug present therein should be stable at gastric pH.

4. What is the characteristic of delayed release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Release as soon as comes in contact to the saliva

Answer: c
Clarification: The design of delayed release systems involves the release of the drug only at a specific site in the GIT. The drugs which are included in such system are destroyed in the stomach or by intestinal enzymes. These drugs are known to gastric distress and absorbed from a specific intestinal site.

5. What is the characteristic of dissolution controlled release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Very slow dissolution rate

Answer: d
Clarification: Dissolution controlled release system is easiest to design. The drug of such system may be inherently slow dissolution, such drugs act as natural prolonged release products. These drugs form slow dissolving forms when it comes in contact with GI fluids. These drugs have high aqueous solubility.

6. What is the characteristic of matrix dissolution-controlled release systems?
a) Release the drug along the entire length of GIT
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution

Answer: d
Clarification: Matrix drugs are homogenous drugs since they are dispersed throughout the drug in a rate controlling medium. They employ wax such as beeswax, hydrogenated castor oil, etc. the drug is often first order from such matrixes. The wax embedded drug is prepared by dispersing the drug in molten wax and granulating it.

7. What is the characteristic of encapsulation or coating dissolution-controlled release systems?
a) Microencapsulation using slowly dissolving materials
b) Prolonged their residence in the GIT and release
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution

Answer: a
Clarification: When drugs are encapsulated with slowly dissolving materials such as that of cellulose, PEG, waxes, etc. The pellets may be filled up in hard gelatin capsules and then compresses to form into tablets. The dissolution rate of the coat depends upon the solubility and thickness of the coat.

8. What are the characteristics of diffusion-controlled release systems?
a) Release the drug along the entire length of GIT
b) Diffusion of the dissolved drug
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution

Answer: b
Clarification: The rate controlling step is the diffusion of the dissolved drug through a polymeric barrier. The drug release rate is never 0. The diffusional path length increases with time as the insoluble matrix gradually depletes from the drug. Two types of diffusion-controlled systems are matrix systems and reservoir systems.

9. What are the characteristics of Matrix diffusion-controlled release systems?
a) Release the drug along the entire length of GIT
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Release only at a specific drug
d) Employ waxes to control the rate of dissolution

Answer: b
Clarification: In this system, the drug is dispersed into an insoluble matrix of a rigid nonswellable hydrophobic material or swellable hydrophilic material. Materials such as insoluble plastic PVC and fatty acids are used as rigid matrix. The drug is generally kneaded with the plastic material.

10. What are the characteristics of reservoir devices-controlled release systems?
a) Release the drug along the entire length of GIT
b) Drug disperse in the insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Employ waxes to control the rate of dissolution

Answer: c
Clarification: These systems are hollow which contains an inner core of drug surrounded in a water-insoluble polymer membrane. The drug release mechanism involves partitioning into the membrane with subsequent release into the surrounding fluid by diffusion.

11. What are the characteristics of ion exchange resin drug complexes?
a) Release the drug along the entire length of GIT
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins

Answer: d
Clarification: Ionisable acidic and basic drugs are complexed with insoluble anion or cation exchange resins. The drug is released slowly by diffusion through the resin particle. Thus the controlled released of the drug is maintained. Drugs such as noscapine have been utilized by such methods.

12. What is the characteristic of pH-independent formulations?
a) Buffering agents that adjust pH to the desired value
b) Drug disperse in the insoluble matrix of rigid hydrophobic materials
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins

Answer: a
Clarification: pH independent formulations are designed such that they can eliminate any changes in the drug property by the changing GI pH. This is done by formulating them with sufficient amount of buffering agents such as phosphoric acid, tartaric acid, citric acids. These formulations adjust the pH to the desired value.

13. What are the characteristics of osmotic pressure-controlled systems?
a) Buffering agents that adjust pH to the desired value
b) Releases the drug at a zero-order kinetics
c) Hollow systems containing drug surrounded by a polymer membrane
d) Formation of complexes between the drug and anion/cation exchange resins

Answer: b
Clarification: Osmotic pressure-controlled systems works on the principle of osmotic pressure to release the drug at a constant zero order rate. The core of the system comprises of the drug and osmotically active substance which will be surrounded by a rigid semipermeable membrane coating.

14. Osmotic pressure controlled systems work on the principle of osmotic pressure releasing the drug at constant 1st order kinetics.
a) True
b) False

Answer: b
Clarification: Osmotic pressure controlled systems are formulated such that they release the drug constantly at a zero order rate. The core comprises of the drug and an osmotically active substance such as potassium chloride or mannitol which will be surrounded by a rigid semipermeable membrane coating such as ester or cellulose ester.

15. What are the characteristics of hydrodynamic pressure controlled systems?
a) Buffering agents that adjust pH to the desired value
b) Drug disperse in an insoluble matrix of rigid hydrophobic materials
c) Generated by swelling hydrophilic hum
d) Formation of complexes between the drug and anion/cation exchange resins

Answer: c
Clarification: In hydrodynamic pressure controlled systems we use the hydrodynamic pressure generated by swelling a hydrophilic gum. The formulation comprises of rigid, shape-retaining house enclosing a collapsible, impermeable compartment containing the liquid drug. The systems are also called push-pull osmotic pumps.

Pharmaceutical Biotechnology Questions and Answers for Campus interviews on “Methods of Immobilization”.

1. Why are Enzymes active only over small range of pH?
a) Its enzymes property
b) Due to non-active site functional group charges
c) Due to the active site functional group charges
d) It prevents from structure destruction

Answer: c
Clarification: Enzyme are active only over small range of pH due to the active site functional group charges (ionic form) and the three dimensional shape of enzyme are pH-dependent. Certain enzyme have ionic group on their active sites, and these ionic group must be in a suitable form (acid or base) to function.

2. What is the suitable form of ionic group of enzymes?
a) Acidic or basic
b) Acidic
c) Basic
d) neutral

Answer: a
Clarification: Certain enzyme have ionic group on their active sites, and these ionic group must be in a suitable form (acid or base) to function. Variation in pH of medium result in changes of ionic form of the active site, activity of enzyme, hence the reaction rate, affect the maximum reaction rate, K_m stability of the enzyme.

3. Variation in pH of medium result in changes of ionic form of the active site.
a) True
b) False

Answer: a
Clarification: Variation in pH of medium result in changes of Ionic form of the active site and activity of enzyme, hence the reaction rate. Variation in pH of medium can also result in changes of the maximum reaction rate, K_m stability of the enzyme. Enzyme are active only over small range of pH due to the active site functional group charges (ionic form) and the three dimensional shape of enzyme are pH-dependent.

4. If the substrate contains ionic groups, what happens to the pH of the medium?
a) The pH of medium increases
b) The pH of medium decreases
c) The pH of medium remains same
d) The pH of medium affects the affinity of substrate to enzyme

Answer: d
Clarification: Some cases, the substrate may contain ionic groups, and the pH of medium affects the affinity of substrate to enzyme. This may lead to major changes in the binding of the enzyme to the substrate. This may damage some vital reactions in our body.

5. The rate of enzyme conversion of the substrate will decrease with temperature.
a) True
b) False

Answer: b
Clarification: It will increase. The rate of enzyme conversion of the substrate will increase with temperature up to an optimum. Above this temperature, enzyme activity will decrease as enzyme denatures. Thermal denaturation of the enzyme can occur after a certain point of increased temperature.

6. What is the term given to restriction of enzyme mobility in a fixed space?
a) Enzyme deactivation
b) Enzyme saturation
c) Enzyme activation
d) Enzyme immobilization

Answer: d
Clarification: Immobilized enzymes refers to enzymes being physically confined to or has been localised in a defined region of space. This also helps them to retain their catalytic activities which can be used continuously. The containment of enzyme solution within a confined space for the purpose of retaining and re-using enzyme in processing equipment.

7. What is the product obtained from glucose isomerase?
a) Amino acids
b) High fructose corn syrup
c) Penicillin
d) Acrylamide

Answer: b
Clarification: In corn syrup production the starch is broken down by enzymes. To make, high fructose corn syrup, the corn syrup has to be further broken down or processed by glucose isomerase. This step helps to convert some of the glucose into fructose.

8. Which enzyme gives Acrylamide as a product?
a) Nitrile Hydratase
b) Glucose isomerase
c) Penicillin acylase
d) Beta-Galactosidase

Answer: a
Clarification: Acrlamide is a monomer which is used for production of a lot of substances. It is produced by the addition of water to acrylamide. The catalyst used in this process is nitrile hydratase. This catalyst is difficult to regenerate. Thus we have to use immobilised nitrile hydrates.

9. Catalyst reuse is an advantage of immobilized enzyme systems.
a) True
b) False

Answer: a
Clarification: The enzymes which were immobilized can be reused. Since the enzymes f=don’t get wash off fully, and the active sites are preserved by staking the enzymes all together in a polyester gel. This has advantages of easier operation, easier product separation, and wider choice of reactors.

10. Why is the enzyme solution mixed with a polymeric fluid?
a) To make it more potent
b) Faster reaction
c) More active sites on the surface
d) Solidifies into various forms

Answer: d
Clarification: The enzyme solutions are mixed with a polymeric fluid which will solidify the enzymes into various forms. The solidification depends on application. The polymeric material is semi-permeable. Large is the molecular weight enzymes cannot diffuse out, small substrate and product molecules can.

11. Which one is a matrix for entrapment?
a) Cellulose
b) Polysulfone
c) Nylon
d) Collagen

Answer: d
Clarification: The matrices for entrapment are Ca- alginate, agar, polyacrylamide, collagen. Membrane materials are enzyme solutions which will be confined between thin semipermeable membranes. Membrane materials include nylon, cellulose, polysulfone, polyacrylate.

12. Membrane materials include: Nylon, cellulose, polysulfone and _______________
a) Collagen
b) Polyacrylamide
c) Agar
d) Polyacrylate

Answer: d
Clarification: Membrane materials are the materials by which the membrane will be constructed. The enzyme solution may be confines between thin semi permeable membranes. Membrane materials include nylon, cellulose, polysulfone, polyacrylate.

13. Which membrane configuration is used for separating enzyme from substrate and product solution?
a) Packed column reactor
b) Hollow fibre configuration
c) Fluidized bed reactor
d) Stirred tank reactor

Answer: b
Clarification: Hollow fibre configuration is a very popular arrangement for separating enzyme from substrate and product can be taken out easily. Hollow fibres containing a stationery enzyme solution. Mobile fluid outside fibres containing substrate and products.

14. What is the name of the method used to cross link enzyme molecules with each other using agents such as glutaraldehyde?
a) Cross linking
b) Polyacrylamide
c) Agar
d) Polyacrylate

Answer: a
Clarification: Cross-linking is to cross link enzyme molecules with each other using agents such as glutaraldehyde. Features are similar to covalent bonding. Several methods of crosslinking are combined.