Chapter-Microbial cell culture and its applications

  • Board
    CBSE
  • Textbook
    NCERT
  • Class
    Class 12
  • Subject
    Biotechnology
  • Chapter
    Chapter-Microbial cell culture and its applications
  • Chapter Name
    Microbial cell culture and its applications
  • Category
    CUET (Common University Entrance Test) UG

Important MCQ-Based Questions for CUET Biotechnology chapter-Microbial cell culture and its applications

This page consists of Important MCQ questions from the chapter-Microbial cell culture and its applications uploaded as per the CUET syllabus and consists of a detailed explanation. Questions are prepared from the entire chapter-Microbial cell culture and its applications to give you effective revision. 

Find below MCQ-Based Questions for CUET Biotechnology chapter-Microbial cell culture and its applications

Important MCQ-based questions Biotechnology CUET chapter-Microbial cell culture and its applications Set-A

Biotechnology - MCQ on Microbial Cell Culture And Its Application

Class XII

Q.1 Which of the following is a chemical mutagen?

a) UV rays

b) X rays and rays are physical mutagens.

c) Nitrosoguanidine

d) Gamma rays

Answer:

c) Nitrosoguanidine is used as chemical mutagen, whereas UV rays

Q.2 Which of the following methods are used for strain improvement?

a) Genetic engineering

b) Down stream processing

c) Scale- up

d) Sterilization

Answer:

a) Recombinant DNA technology is used for strain improvement.

Q.3 Which of the following substance is used as cryoprotectant?

a) MMS

b) Nitrous oxide

c) Glycerol

d) Agar

Answer:

c) Glycerol is used as cryoprotectant as it avoid the formation of ice crystal in liquid nitrogen.

Q.4 Bacteria grow by which of the following way?

a) Budding

b) Binary fission

c) Elongation

d) Branching]

Answer:

a) Bacteria grow by binary fission.

Q.5 Baffles are

a) Antifoaming agents

b) Aeration components

c) Agitation components

d) Other name of sparger

Answer:

c) Baffles are used for agitation in a fermenter.

Q.6 Olive oil is used as

a) Antifoam agent

b) Growth media

c) Mutagen

d) Antibiotic

Answer:

a) Olive oil is used as antifoaming agent in a fermenter.

Q.7 IMTECH is situated at

a) Pune

b) Chandigarh

c) Kolkota

d) Delhi

Answer:

(b) IMTECH (India at Institute of Microbial Technology is in Chandigarh.

Q.8 Culture preservation at -196° is called

a) Lyophilization

b) Cryopreservation

c) Dry preservation

d) Ampoule

Answer:

b) The culture preservation at -196° is called as Cryopreservation.

Q.9 The microbial culture efficiency is

a) 0-10 %

b) 50-60%

c) 20-30%

d) 100%

Answer:

c) The efficiency of chemical reaction is 80- 90% but the microbial conversion efficiency is 20- 30% as the organism for growth and multiplication utilizes a large part of the substrates.

Q.10 Which of the following is a synthetic media?

a) Peptone

b) Beef extract

c) Yeast extract

d) Mannitol salt agar

Answer:

d) Mannitol salt agar is a synthetic media.

Q.11 Cassava is a source of

a) Carbon

b) Nitrogen

c) Mineral

d) Oil

Answer:

a) Cassava is used a source of carbon in a growth media for microbes

Q.12 Corn steep liquor is the source of

a) Lactic acid

b) Polysaccharide

c) Sugars

d) Nitrogen

Answer:

Corn steep liquor is a rich source of nitrogen.

Q.13 Sterilization can be achieved by

a) High pressure and heat

b) Growth media

c) Liquid nitrogen

d) Cryopreservation

Answer:

a) Sterilization can be achieved by high pressure and heat.

Q.14 Sterilization of nutrient media can be done at

a) 20 psi for 5 minutes

b) 70 psi for 10 minutes

c) 15 psi for 15 minutes

d) 30 psi for 10 minutes.

Answer:

c) Sterilization of nutrient media can be done at 15 psi for 15 minutes.

Q.15 Animal cell culture is sterilized by

a) Filtration

b) Heating

c) Irradiation

d) Ultrasonic treatment.

Answer:

a) Animal cell culture is sterilized by filtration as such media are completely soluble and contain heat labile components.

Q.16 Bacteria grow at which pH?

a) Acidic

b) Basic

c) Neutral

d) Amphoteric

Answer:

c) Bacteria grow at Neutral pH.

Q.17 On large-scale, fermenter is sterilized by

a) Steam

b) Pressure

c) Ultrasonic treatment

d) Chemicals

Answer:

a) On large-scale, fermenter is sterilized by steam.

Q.18 In laboratory aeration and mixing is done by

a) Autoclave

b) Shaker

c) Baffles

d) Sparger

Answer:

b) When microbes are cultivated in the laboratory aeration and mixing can be done by putting the flasks on the shakers.

Q.19 Impeller is a kind of

a) Agitator

b) Baffle

c) Sparger

d) Cooling jacket

Answer:

a) Impeller is a kind of agitator.

Q.20 In stirred tank fermenter agitation and aeration is done by

a) Sparger

b) Coils

c) Impeller

d) Baffles

Answer:

c) In stirred tank fermenter agitation and aeration is done by impeller.

Q.21 Lag phase is also known as

a) Trophophase

b) Log phase

c) Stationary phase

d) Adaptation phase

Answer:

d) After inoculation in fermentor no cell growth occurs for sometimes it is called time of adaptation or lag phase.

Q.22 Log phase is also known as

a) Trophophase

b) Lag phase

c) Stationary phase

d) Adaptation phase

Answer:

a) The cell grows gradually and thereafter show maximum growth rate. This period is called trophophase or log phase or exponential growth phase.

Q.23 In continuous culture the growth retards due to

a) Accumulation of nutrients

b) Accumulation of toxic products

c) Depletion of nutrients

d) Death of microbes

Answer:

c) In continuous culture the growth retards due to depletion of nutrients not due to accumulation of toxic products.

Q.24 In continuous culture exponential phase is prolonged by

a) Accumulation of toxic product

b) Depletion of nutrients

c) Adding fresh media

d) Removal of microbes

Answer:

c) Adding of fresh medium to the fermenter and removal of spent medium and microbial biomass from it results in prolonged exponential phase.

Q.25 In turbidostat the concentration of cell is kept constant by

a) Limiting chemical component of medium

b) Controlling flow of medium

c) Removal of spent media

d) Removal of microbes.

Answer:

b) In turbidostat the concentration of cells in the culture is kept constant by controlling the flow of medium. Such that turbidity of the culture is kept in narrow limits.

Q.26 Fungi divide by

a) Budding

b) Binary fission

c) Chain elongation

d) Intracellularly in host cells

Answer:

c) Fungi divide by chain elongation and branching.

Q.27 Separation of cells from the fermented broth is done by

a) Centrifugation

b) Filtration

c) Chromatography

d) Solvent extraction

Answer:

a) Separation of cells from the fermented broth is done by centrifugation or ultrafiltration.

Q.28 Enrichment culture

a) Enhances growth of organism

b) Reduces growth of organism

c) Does not have any effect on growth of organism

d) Stops the growth of organism.

Answer:

a) Enrichment liquid culture is a technique resulting in an increase in the number of a given organism relative to the numbers of other types of organism. The process involves taking a mixed population and providing conditions suitable for the growth of desired organism.

Q.29 Screening of microorganism can be done by

a) Filtration

b) Centrifugation

c) Microarray

d) Chromatography

Answer:

c) Microarray technique allows robotic automation that permits the screening of large number of microorganisms.

Q.30 Chlortetracycline is produced from

a) Penicillium chrysogenum

b) Streptomyces viridifaciens

c) Rhizopus oligosporus

d) Pseudomonas

Answer:

b) Streptomyces viridifaciens that produces chlortetracycline. Ultraviolet treatment is used to mutate it and from which it may be seen that the mutated strain produces more than twice chlortetracycline than the natural variants.

Q.31 Glycerol is used for

a) Lyophilization

b) Dry cultures

c) Agar storage

d) Cryopreservation

Answer:

d) Cells are suspended in cryoprotective agents like 10% glycerol and sealed in ampoules and then frozen in liquid nitrogen.

Q.32 Which of the following is a primary metabolite

a) Antibiotics

b) Toxins

c) Pigments

d) Vitamins

Answer:

d) A primary metabolite is directly involved in normal growth, development, and reproduction. Primary metabolites like alcohols, acids, and vitamins are microbial products are produced during exponential growth phase.

Q.33 Vaccines for typhoid is developed from

a) Primary metabolite

b) Secondary metabolite

c) Whole cell organism

d) Spirulina maxima

Answer:

c) Vaccines for typhoid, tetanus and tuberculosis have been prepared by using whole cells of bacteria.

Q.34 Tempeh is fermented by

a) Rhizobium

b) Pseudomonas

c) Rhizopus oligosporus

d) Canidida utilis

Answer:

c) Tempeh is a Javanese food made from fermentation of soybean by Rhizopus oligosporus into a cake form. Tempeh’s fermentation process and its retention of whole bean give it a higher content of protein, dietary fiber and vitamins.

Q.35 Which of the following is a secondary metabolite

a) Antibiotics

b) Alcohol

c) Acid

d) Vitamins

Answer:

a) A secondary metabolite is not directly involved in those processes, but usually has an important ecological function. Examples include antibiotics and pigments, and toxins. Secondary metabolite are produced during stationary phase of growth.

Q.36 Vinegar is produced by

a) Primary metabolite

b) Secondary metabolite

c) Whole cell organism

d) Biotransformation

Answer:

d) Microbial cells may be used to convert a compound into a structurally related, financially more valueable, compound. Although the production of vinegar is the most well known microbial transformation process.

Q.37 L- Lysine is produced by

a) Saccharomyces cerevisiae

b) Corynebacterium glutamicum

c) Aspergillus oryzae

d) Escherichia coli

Answer:

b) L- Lysine is produced by Corynebacterium glutamicum.

Q.38 Semi synthetic media contain which of the following component

a) Nitrogen

b) Carbon

c) Peptone

d) Minerals

Answer:

c) There are a number of readily available commercial media such as LB media, LB broth, nutrient media, nutrient broth, mannitol salt agar, and MacConkey agar etc. These media contain complex components such as peptone, beef extract, yeast extract, and casein. Such media are called semi- synthetic media.

Q.39 Barley grains is the source of

a) Carbon

b) Nitrogen

c) Ammonia

d) Trace element

Answer:

a) Barely grains may be partially germinated and heat-treated to give malt, which contains sugar and starch.

Q.40 The most common cause of foaming is

a) Growth factors

b) Proteins

c) Carbohydrate

d) Acids

Answer:

b) The most common cause of foaming is due to proteins in the medium, such as corn steep liquor, peanut meal, soybean meal.

Q.41 Foaming causes

a) Regeneration of cells

b) Removal of cells

c) Formation of air layer on the cells

d) Formation of oil layer on the cells

Answer:

b) foaming can cause removal of cells from medium that will lead to autolysis. If uncontrolled, then numerous changes may occur and physical and biological problems may be created.

Q.42 Sulphonates are used as

a) Sulphur source

b) Ammonia source

c) Antifoaming agent

d) Nitrogen source

Answer:

c) Sulphonates are used as antifoaming agent

Q.43 Fungi and yeast grow at

a) Acidic

b) Basic

c) Neutral

d) Amphoteric

Answer:

a) Bacteria grow at neutral pH whereas fungi and yeast grow at acidic pH. Therefore before autoclaving the medium the pH is balanced according to the need.

Q.44 Antifoaming agents can be sterilized by

a) Irradiation

b) Steam

c) Heat

d) Pressure

Answer:

c) Antifoaming agents can be sterilized by heat.

Q.45 Batch culture is a

a) Closed system

b) Open system

c) Isolated system

d) Bithermal system

Answer:

c) It is the simplest type of closed culture system in which microorganism grow in a vessel known as fermenter provided with limited amount of medium containing all the nutrient at optimum environmental conditions.

Q.46 Deceleration phase is also known as

a) Trophophase

b) Lag phase

c) Stationary phase

d) Adaptation phase

Answer:

c) Deceleration phase is also known as stationary phase. It is due to consumption of nutrients, which is called substrate limitation.

Q.47 Ordinary laboratory flask is

a. Batch culture

b. Fed batch culture

c. Continuous culture

d. Stirred culture

Answer:

a) Culturing microbes in the laboratory, in a ordinary flask, is basically a batch culture.

Q.48 Chemostat is controlled by

a) Limiting chemical component of medium

b) Controlling flow of medium

c) Removal of spent media

d) Removal of microbes

Answer:

a) In chemostat growth is controlled by the availability of the growth limiting chemical component of the medium.

Q.49 Concentration of the microbial culture can be calculated by

a) Measuring the wavelength

b) Measuring the absorbance

c) Measuring the dry weight

d) Measuring the cell number

Answer:

b)The cell concentration of the unknown microbial sample can be calculated by measuring the absorbance at the same wavelength.

Q.50 Coulter counter is used for

a) ATP measurement

b) Measurement of weight

c) Count cell

d) Turbidity measurement

Answer:

c) Coulter counter is an electronic instrument and is used for direct counting of microbial cells in suspension.

Biotechnology - MCQ on Additional Questions

Important MCQ-based questions Biotechnology CUET chapter-Microbial cell culture and its applications Set-B

Q.51 Corn steep liquor is a by-product of

a) nitrogen.

b) starch.

c) sugars.

d) carbon.

Answer:

(b)

Explanation: Corn steep liquor is a by-product of starch; primarily used as nitrogen source, contains lactic acid, sugar and polysaccharides.

Q.52 In microbial culture, inorganic nitrogen is supplied as

a) urea.

b) protein.

c) ammonia gas.

d) amino acid.

Answer:

(c)

Explanation: Inorganic nitrogen may be supplied as ammonia gas, ammonium salts or nitrates.

Q.53 Agar is a

a) trace element

b) vitamin.

c) polysaccharide.

d) protein.

Answer:

(c)

Explanation: Agar is a gelatinous substance derived from seaweed; Gelidium amansii.

Q.54 To minimize pH

a) carbon is used.

b) phosphate is used.

c) vitamins are used.

d) copper is used.

Answer:

(b)

Explanation: Phosphate is used as a buffer to minimize pH.

Q.55 Esters can be used as

a) carbon source.

b) antifoams.

c) trace elements.

d) nitrogen source.

Answer:

(b)

Explanation: Foaming is a big problem in microbial culture. Alcohols and esters are used as antifoaming agents.

Q.56 In a microbial culture the energy comes from the

a) movement of media.

b) addition of nutrients.

c) oxidation of medium.

d) aeration of medium.

Answer:

(c)

Explanation: Energy for growth comes either from the oxidation of medium components or light.

Q.57 Water used in laboratory is

a) sea water.

b) mineral water.

c) fresh water.

d) single distilled water.

Answer:

(d)

Explanation: Water is the major component of all fermentation media. For laboratory use, single distilled or double distilled water is adequate.

Q.58 Autolysis of cells may be caused by

a) metabolism of media.

b) degradation of media.

c) heating of jacket.

d) foaming in media.

Answer:

(d)

Explanation: In microbial processes foaming is a problem.

Foaming can cause removal of cells from medium that will lead to autolysis.

Q.59 An ideal foaming agent must be

a) expensive.

b) in high concentration.

c) metabolized by microorganisms.

d) nontoxic.

Answer:

(d)

Explanation: It should disperse readily and have fast action on existing foam. It should be active also at low concentration and nontoxic to microorganism.

Q.60 Sugarcane is the major sources of

a. glucose.

b. lactose.

c. fructose.

d. sucrose.

Answer:

(d)

Explanation. Sucrose is the most important sugar in plants. It is generally extracted from sugar cane or sugar beet and then purified and crystallized.

Q.61

Barely grains may be partially germinated and heat-treated to give

a. proteins.

b. vitamins.

c. malt.

d. lipids.

Answer:

(c)

Explanation. Barely grains may be partially germinated and heat-treated to give malt, which contains sugar and starch.

Q.62 Commonly used antifoams are

a. acetic acids.

b. citric acids.

c. fatty acids.

d. formic acids.

Answer:

(c)

Explanation. In most microbial processes foaming is a problem. It may be due to a component in the medium or some factor produced by the microorganism. Commonly used antifoams are fatty acids such as olive oil or sunflower oils.

Q.63. The most common source of energy is

a. nitrogen source.

b. carbon source.

c. phosphorous source.

d. ammonia source.

Answer:

(b)

Explanation. The most common source of energy is carbon source such as carbohydrates, lipids and proteins.

Q.64 Sterilization of the nutrient medium can be done by

a. autoclave.

b. shaker.

c. baffles.

d. sparger.

Answer:

(a)

Explanation. When microbes are cultured in the laboratory, sterilization of the nutrient medium can be done in an autoclave at 15 psi for 15- 20 minutes or heating the medium at 120°C for 15- 20 minutes.

Q.65 Viruses grow by

a. budding.

b. binary fission.

c. sexual reproduction.

d. intracellularly in host cells.

Answer:

(d)

Explanation. Viruses normally do not follow a regular growth pattern as they grow intracellularly in host cells.

Q.66 Cell counting is generally carried out in

a. concentrated culture.

b. dilute culture.

c. semisolid media.

d. high density cultures.

Answer:

(b)

Explanation. Cell counting is generally carried out in dilute culture as high cell density presents problems in counting.

Q.67 Direct counting of microbial cells in suspension is possible with the help of

a. coulter counter.

b. spectrophotometer.

c. counting slide.

d. cell cytometry.

Answer:

(a)

Explanation. Coulter counter is an electronic instrument and is used for direct counting of microbial cells in suspension.

Q.68The oldest method of strain improvement is

a. mutant selection.

b. culture selection.

c. genetic engineering.

d. recombinant DNA technology.

Answer:

(a)

Explanation. Mutant selection is one of the oldest methods of strain improvement.

The strain is exposed to chemicals (e.g. nitrosoguanidine or NTG) or physical (UV rays) mutagens and the mutants having improved chacteristic are selected.

Q.69 Streptomyces viridifaciens produce

a. ampicillin.

b. humulin.

c. chlortetracycline.

d. penicillin.

Answer:

(c)

Explanation. Streptomyces viridifaciens produce chlortetracycline. Ultraviolet treatment is used to mutate it from which it may be seen that the mutated strain produces more than twice amount of chlortetracycline than the natural variants.

Q.70 Cultures grown on agar slopes may be stored in a refrigerator at

a. 5° C.

b. -5° C.

c. -27° C.

d. -196° C.

Answer:

(a)

Explanation. Cultures grown on agar slopes may be stored in a refrigerator (5°) or a freezer (-20°) and subcultured around every six months interval.

Q.71 The long-term preservation of tissues and cells at ultra-low temperature is called

a. cold storage.

b. cryopreservation

c. dried culture.

d. stirred culture.

Answer:

(b)

Explanation. This process utilizes the long-term preservation of tissues and cells at ultra-low temperature i.e. in liquid nitrogen (-1960C) by using cryoprotectants e.g. glycerol, proline, dimethylsulfoxide and mannitol.

Q.72 The cryopreservative temperature is maintained at

a. 00C.

b. -40C.

c. -470C.

d. -1960C.

Answer:

(d)

Explanation. Cryopreservation process utilizes the long-term preservation of tissues and cells at ultra-low temperature i.e. in liquid nitrogen (-1960C) by using cryoprotectants e.g. glycerol, proline, dimethylsulfoxide and mannitol.

Q.73 Dimethyl sulfoxide (DMSO) is a

a. cryopreservative.

b. trace element.

c. natural media.

d. artificial media.

Answer:

(a)

Explanation. The cryopreservative DMSO is a small molecule, which is soluble in lipids and generally added to minimize injury to cells during freezing and thawing.

Q.74 Sporulating mycelial organisms are preserved by

a. cold storage.

b. cryopreservation.

c. dried culture.

d. stirred culture.

Answer:

(c)

Explanation. Dried soil cultures have been used widely for culture preservation, particularly for sporulating mycelial organisms.

Q.75 Freezing of a culture followed by drying under vacuum is

a. cold storage.

b. lyophilization.

c. dried culture.

d. vacuum culture.

Answer:

(b)

Explanation. Lyophilization or freeze drying involves the freezing of a culture followed by its drying under vacuum, which results in sublimation of the cell water.

Q.76 Sterilization of the nutrient medium can be done by heating the medium at

a. 68°C.

b. 98°C.

c. 120°C.

d. 180°C.

Answer:

(c)

Explanation. When microbes are cultured in the laboratory, sterilization of the nutrient medium can be done in an autoclave by heating the medium at 120°C and 15 psi for 15- 20 minutes.

Q.77 In a fermenter sterile air or steam is passed with the help of

a. impeller.

b. shaker.

c. baffles.

d. sparger.

Answer:

(d)

Explanation. Sparging involves passing sterile air or steam through the medium by having a sparger device at the bottom of the fermenter.

Q.78 The role of sparger in a fermenter is to

a. maintain osmolality.

b. control of pH.

c. control of temperature.

d. maintain the entry of air.

Answer:

(d)

Explanation. In a fermenter, sparger is used to introduce air or gas into the liquid medium.

Q.79 The normal buffer system in tissue culture media is the

a. CO2 bicarbonate system.

b. CO2 carbonate system.

c. O2 bicarbonate system.

d. O2 carbonate system.

Answer:

(a)

Explanation. The pH and temperature of the medium influences the growth of the microorganism. The normal buffer system in tissue culture media is the CO2 bicarbonate system.

Q.80. A pH probe is attached inside the fermenter, which always remains in contact with

a. sparger.

b. growth medium.

c. impeller.

d. baffles.

Answer:

(b)

Explanation. The disturbance of pH to the addition of acid makes pH control very difficult by conventional means. For this purpose, a pH probe always remains in contact with growth medium.

Q.81 On small scale, autoclaving can be performed in

a) microwave oven.

b) OTG.

c) pressure cooker.

d) tandoor.

Answer:

(c)

Explanation: For small- scale laboratory culture, tubes and flasks can be sterilized in a pressure cooker.

Q.82 Contamination can be avoided by

a) washing the materials with water.

b) boiling the media.

c) using mixed culture.

d) sterilizing the vessel.

Answer:

(d)

Explanation: The contamination may be avoided by

a) Using a pure inoculum.

b) Sterlizing the medium.

c) Sterilizing the fermenter vessel.

d) Sterilizing all materials added.

e) Maintaining aseptic conditions during the fermentation.

Q.83 Steam pressure for sterilization is

a) 5 psi.

b) 15 psi.

c) 35 psi.

d) 50 psi.

Answer:

(b)

Explanation: Sterlization of fermenter vessel is normally done by heating the jacket or coils of the fermenter with steam and sparging steam into the vessel through all the entry points.

Steam pressure is held at 15 psi for 20 minutes.

Q.84 Weak buffer system can be improved by

a) taking the pH.

b) using zwitter ion.

c) controlling the temperature.

d) autoclaving the system.

Answer:

(b)

Explanation: The normal buffer system in tissue culture media is the CO2 bicarbonate system. This is a weak buffering system and can be improved by use of zwitter ion.

Q.85 pH is maintained

a) after autoclaving.

b) before dissolving complete media.

c) before autoclaving.

d) before sterlization.

Answer:

(c)

Explanation: Bacteria grow at neutral pH whereas fungi and yeast grow at acidic pH. Therefore before autoclaving the medium the pH is balanced according to the need.

Q.86 Rate of reaction is controlled by

a) pH.

b) media.

c) temperature.

d) water.

Answer:

(c)

Explanation: Microorganisms are classified according to the temperature at which they grow optimally. Temperature controls the rate of reaction that influences the growth rate of the organism.

Q.87 Animal cell culture is sterilized by filtration as it contains

a) heat labile substances.

b) substances that catch fire.

c) water that evaporates on heating.

d) insoluble substances.

Answer:

(a)

Explanation: Filtration is used for animal cell culture sterlization as these media are completely soluble and contain heat labile components.

Q.88 Hot air oven is used for the sterilization of

a) media.

b) solutions.

c) pipette tips.

d) glasswares.

Answer:

(d)

Explanation: Hot air oven is widely used in laboratories to sterilize glasswares. The glasswares are dry heated at 180oC for 20 minutes or 190oC for 12 minutes.

Q.89 In hot air oven

a) radiations are used.

b) dry heat is used.

c) steam is used for sterilization.

d) HEPA filters are used.

Answer:

(b)

Explanation: Hot air oven is electrical device used in sterilization of glasswares. It uses dry heat to sterilize articles. Generally it can be operated between 50 to 300oC.

Q.90 The optimum temperature for growth of psychrophiles is

a) 55oC.

b) 46oC.

c) 37oC.

d) 15oC.

Answer:

(d)

Explanation: According to optimum temperatures for the growth of microorganisms, these are divided into following categories–

Psychrophiles: ~15oC

Mesophiles: ~37oC

Thermophiles: ~55oC.

Q.91 Shakers are used for

a) sterilization.

b) filtration.

c) mixing.

d) grinding.

Answer:

(c)

Explanation: When microbes are cultivated in the laboratory, aeration and putting the flasks on the shakers can do mixing.

Q.92 Oxygen demand in a fermenter is met by

a) steam.

b) mixing.

c) aerobic bacteria.

d) tube culture.

Answer:

(b)

Explanation: Aerating and agitating (mixing) the fermentation broth normally meet the oxygen demand of the fermenter.

Q.93 Erlenmeyer flasks is used for

a) large scale culture.

b) preservation of culture.

c) laboratory culture.

d) detecting growth of microorganisms.

Answer:

(c)

Explanation: In laboratory, microbes are cultivated in test tubes or Erlenmeyer flasks. Such cultures are carried out in 100- 1000 ml volume.

Q.94 Baffle flask is used for

a) aseptic culture.

b) improved growth of microorganisms.

c) industrial production.

d) high volumes of culture.

Answer:

(b)

Explanation: Baffle flask has a V shaped notch in the sides of flask. This improves the growth of the microbes by providing greater agitation of solutions to improve oxygen or gas transfer.

Q.95 Pilot plants are used for

a) large scale production.

b) sterilization of nutrients.

c) optimization of fermentation process.

d) remove the contaminants.

Answer:

(c)

Explanation: The first step in production of any microbial product is its research in laboratory. Before going to industrial production it is produced in the pilot plant to standardize the conditions.

Q.96 Stationary phase is also known as

a) log phase.

b) lag phase.

c) deceleration phase.

d) death phase.

Answer:

(c)

Explanation: After log phase the growth decreases it is called deceleration phase. It is due to consumption of nutrients, which is called substrate limitation, which results in stationary phase.

Q.98 In continuous culture

a) log phase is prolonged.

b) one nutrient is in limited quantity.

c) no raw material is added.

d) growth stops due to toxic products.

Answer:

(b)

Explanation: In continuous culture the production is continuous. The growth medium is formed in such a way that one of the nutrients is in limited quantity. Adding of fresh medium just before the nutrient get exhausted prolongs the growth.

Q.99 In turbidostat

a) amount of media is constant.

b) concentration of cells is constant.

c) production is constant.

d) the chemicals are constant.

Answer:

(b)

Explanation: In turbidostat the concentration of cells in the culture is kept constant by controlling the flow of medium. Such that turbidity of the culture is kept in narrow limits.

Q.100 Yeast divides by

a) budding.

b) fission.

c) sexual reproduction.

d) congugation.

Answer:

(a)

Explanation: All these microorganisms grow in different ways

a) Bacteria grow by binary fission

b) Yeast divides by budding

c) Fungi divide by chain elongation and branching

d) Viruses normally do not follow a regular growth pattern as they grow intracellularly in host cells.

Plant Cell Culture and Applications