BIOCHEMICAL ENGINEERING Flashcards by Iana Cruz

Linear inhibition is sometimes called as

A complete inhibition
B incomplete inhibtion
C partial inhibition
D mixed inhibition

COMPLETE INHIBITION

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A competitive inhibitor of an enzyme is usually

A a highly reactive compound
B a metal ion such as Hg2+ or Pb2+
C structurally similar to the substrate.
D water insoluble

STRUCTURALLY SIMILAR TO THE SUBSTRATE

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The types of inhibition pattern based on Michaelis Menten equation are

A competitive
B non-competitive
C uncompetitive
D all of the above

COMPETITIVE, NON-COMPETITIVE, UNCOMPETITIVE

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The rate-determining step of Michaelis Menten kinetics is

A the complex formation step
B the complex dissociation step to produce product
C the product formation step
D Both (a)and(c)

THE COMPLEX DISSOCIATION STEP TO PRODUCE PRODUCT

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In competitive inhibition a factor is obtained from the measurement of

A Vmax
B KM
C Y-intercept in Lineweaver-Burk Plot
D None of these

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Which of these proteases is not a cysteine active site protease?

A Calpain
B Cathepsin D
C Papain
D None of the above

CATHPESIN D

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Given an enzyme with a Km = 10m M and Vmax = 100 m mol/min. If [S] = 100 m M, which of the following will be true?

A A 10 fold increase in Vmax would increase velocity 10 fold y

B A 10 fold decrease in Km would increase velocity

C Both (a) and (b)

D A 10 fold increase in Vmax would decrease velocity 20 fold

A 10 fold increase in Vmax would increase velocity 10 fold y

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The conformational change in an enzyme after the substrate is bound that allows the chemical reaction to proceed, can be explained by

A induced fit
B transition
C fit and fine
D Pasteur

INDUCED FIT

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The active site of an enzyme remains

A at the center of globular proteins
B rigid and does not change shape
C complementary to the rest of the molecule
D none of the above

NONE OF THE ABOVE

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The effect of non-competitive inhibition on a Lineweaver-Burk Plot is that

A it can move the entire curve to the right
B it can change the y-intercept
C it can change the x-intercept
D all of these

it can change the y-intercept

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Which category of enzymes belongs to class two in the international classification?

A Hydrolases
B Ligases
C Transferases
D Isomerase

TRANFERASES

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The Woolf-Augusteinsson-Hofstee plot of ν versus ν/[S] and the Eadie-Scatchard plot of ν/[S] versus ν do not involve reciprocals of ν therefore are considered to be more reliable when the error in v is

A non-significant
B significant
C nothing to do with the reliability
D non significant in selected cases

SIGNIFICANT

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The relationship between Keq, Km and Vmax is known as

A Haldane equation
B Michaelis Menten equation
C Numerical solution approach
D Gibbs-Helmholtz equation

HALDANE EQUATION

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The reciprocal equation for non competitive inhibition can be arranged to the equation for the

A Dixon plot
B Woolf-Augusteinsson-Hofstee plot
C Eadie-Scatchard plot
D Hanes-Woolf plot

DIXON PLOT

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The reciprocal equation for non competitive inhibition can be arranged to the equation for the

A Dixon plot
B Woolf-Augusteinsson-Hofstee plot
C Eadie-Scatchard plot
D Hanes-Woolf plot

DIXON PLOT

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Which of the following statements is true for enzymatically catalyzed reaction?

A The activation energy of the reaction is lowered so that a larger proportion of the substrate qualifies to overcome it

B Additional substrate molecules are energized to overcome the activation energy of the reaction

C The activation energy of the reaction is increased, thus decreasing the likelihood that any substrate molecules will overcome it

D The activation energy of the reaction is lowered so that a fewer substrate molecules can overcome it

THE ACTIVATION ENERGY OF THE REACTION IS LOWERED SO THAT A LARGER PORTION OF THE SUBSTRATE QUALIFIES TO OVERCOME IT

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Which of the following common drugs is not a specific enzyme inhibitor?

A Iodine
B Methotrexate
C Sulfbnilamide
D Penicillin

IODINE

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The enzyme inhibition can occur by\

A reversible inhibitors
B irreversible inhibitors
C Both (a) and (b)
D None of these

REVERSIBLE AND IRREVERSIBLE INHIBITORS

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In a Lineweaver-Burk Plot, competitive inhibitor shows which of the following effect?

A It moves the entire curve to right
B It moves the entire curve to left
C It changes the x-intercept
D It has no effect on the slope

IT CHANGES THE X-INTERCEPT

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Which of the following statements is not true?

A Enzymes are proteins that bind to specific substrates and increase the velocity of reactions involving those substrates

B Enzymes function by overcoming the activation energy barrier of a reaction

C Enzymes make thermodynamically favorable reactions to proceed; they cannot make unfavorable reactions to occur

D Enzymes only function when they are in intact cells

ENZYMES ONLY FUNCTION WHEN THEY ARE IN INTACT CELSS

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Non-competitive inhibitor of an enzyme catalyzed reaction

A decreases Vmax
B binds to Michaelis complex (ES)
C both (a) and (b)
D can actually increase reaction velocity in rare cases

decreases Vmax

binds to Michaelis complex (ES)

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An enzyme and a reactant molecule maintain relationship as

A a temporary association
B an association stabilized by a covalent bond
C one in which the enzyme is changed permanently
D non complementary binding

A TEMPORARY ASSOCIATION

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An enzyme is assayed at an initial substrate concentration of 2 x 10-5M. In 6 minute, half of the substrate is used. The Km for the substrate is 2 x 10-3M. The value of k in minute is

A 0.115
B 0.42
C 0.093
D 6.693

0.115

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The plot commonly used for determining the value of Vmax is

A Lineweaver Burk plot
B Langmuir plot
C Eadie Hofstee plot
D all of these

LINEWEAVER BURK PLOT

LANGMUIR PLOT

EADIE HOFSTEE PLOT

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Quasi steady state is also known as A Michaelis Menten approach B Briggs-Haldane approach C Pseudo steady state D all of the above

PSEUDO STEADY STATE

Which of these enzymes contains a Zinc (Zn) ion? A Carboxypeptidase A B Phosphorylase B kinase C Tyrosine hydroxylase D Phosphodiesterase

Carboxypeptidase A

A noncompetitive inhibitor of an enzyme-catalyzed reaction A increases KM and increases Vmax B increases KM and reduces Vmax C reduces KM and increases Vmax D reduces KM and reduces Vmax

increases KM and reduces Vmax

An allosteric inhibitor of an enzyme usually A participates in feedback regulation B denatures the enzyme C is a hydrophobic compound D causes the enzyme to work faster

PARTICIPATES IN FEEDBACK REGULATION

Which of the following activity is possible by transferases? A Transfer of methyl groups B Transfer of glycosyl group C Both (a) and (b) D None of these

Transfer of methyl groups Transfer of glycosyl group

A classical uncompetitive inhibitor is a compound that binds A reversibly to the enzyme substrate complex yielding an inactive ESI complex B irreversibly to the enzyme substrate complex yielding an inactive ESI complex C reversibly to the enzyme substrate complex yielding an active ESI complex D irreversibly to the enzyme substrate complex yielding an active ESI complex

reversibly to the enzyme substrate complex yielding an inactive ESI complex

Which graphical method is used to determine an enzyme degree of cooperativity? A Hill plot B Koshland curve C Michaelis-Menten hyperbola D Can not be determined

HILL PLOT

The ratio of the amount of a protein present in a sample, which is used as a measure of purification, is known as A specific activity B relative activity C purity ratio D all of these

SPECIFIC ACTIVITY

If a reaction occurs in the absence of inhibitor with rate ν0 and in the presence of inhibitor with rate νi, the degree of inhibition is defined as A (ν0 - νi)/ν0 B (ν0 + νi)/ν0 C (ν0νi)/ν0 D (ν0-νi)/νi

(ν0 - νi)/ν0

The rate equation in competitive inhibition based on Michaelis Menten equation is given by A rmaxS/(Km (1+I/Ki)+S)) B rmaxE/(Km (1+I/Ki)+S)) C rmaxI/(Km (1+I/Ki)+S)) D rmaxS/(Km (1+I/Ki))

rmaxS/(Km (1+I/Ki)+S))

Classical noncompetitive inhibition is obtained only under A slow equilibrium conditions B moderate equilibrium conditions C rapid equilibrium conditions D non-equilibrium conditions

RAPID EQUILLIBRIUM CONDITIONS

In the steady state the material balance equation for any component of a system is A rate of addition + rate of removal - rate of formation = 0 B rate of addition - rate of removal + rate of formation = 0 C rate of addition + rate of removal + rate of formation = 0 D none of the above

rate of addition - rate of removal + rate of formation = 0

For an enzyme that displays Michaelis-Menten kinetics, the reaction velocity (as a fraction of Vmax) observed at [S] = 2 KM will be A 0.09 B 0.33 C 0.66 D 0.91

0.66

Predominantly uncompetitive inhibition may be called when A competitive inhibition is greater than uncompetitive inhibition B competitive inhibition is smaller than uncompetitive inhibition C competitive inhibition is equal to uncompetitive inhibition D none of the above

COMPETITIVE INHIBITION IS GREATER THAN UNCOMPETITIVE INHIBITION

An enzyme has a Km of 4.7 x 10-5M. If the Vmax of the preparation is 22m moles liter-1 min-1, what velocity would be observed in the presence of 2.0 x 10-4M substrate and 5.0 x 10-5M of a competitive inhibitor? A 13.54μ moles liter-1min-1 B 6.68μ moles liter-1min-1 C 7.57μ moles liter-1min-1 D 17.8μ moles liter-1min-1

13.54μ moles liter-1min-1

The rate equation in non-competitive inhibition based on Michaelis Menten equation is given by A rmaxS/(Km + S)(1+I/Ki) B rmaxE/(Km (1+I/Ki)+S)) C VmaxS/(Km + S)(1+I/Ki) D rmaxS/Km

rmaxS/(Km + S)(1+I/Ki)

Which of the following statement(s) regarding enzymes, is/are false? A Enzymes are always proteins that function as catalysts B Enzymes provide activation energy for reactions C Enzyme activity can be regulated D Enzymes may be used many times for a specific reaction

ENZYMES PROVIDE ACTIVATION ENERGY FOR REACTIONS

The slope of Lineweaver Burk plot for Michaelis Menten equation is A Vmax/Km B Km/Vmax C 1/Km D Km.Vmax

Km/Vmax

The initial velocity, V0, of an enzyme catalyzed reaction reaches Vmax as A [S] = KM B [S] = 10 * KM C 1/[S] = 1/KM D 1/[S] → 0

1/[S] → 0

The usual method(s) to solve rate equation of simple enzyme kinetics is/are A Michaelis Menten approach B Briggs-Haldane approach C Numerical solution approach D all of these

Michaelis Menten approach Briggs-Haldane approach Numerical solution approach

Michaelis Menten equation can also be written as A (-Cs)/r = (Cs/rmax)+(Km/rmax) B 1/r = (1/rmax)+(Km/(rmax.Cs)) C r = rmax-(Km.r/Cs) D All of these

ALL OF THESE

Which of the following step is assumed to be the slowest step in the Michaelis Menten equation? A The substrate consuming step B The product releasing step C Formation of enzyme substrate complex D None of these

THE PRODUCT RELEASING STEP

When substrate [S] = KM (Michaelis-Menten constant), the velocity of an enzyme catalyzed reaction is about A 0.1 * Vmax B 0.2 * Vmax C 0.5 * Vmax D 0.9 * Vmax

0.5 * Vmax

A classical noncompetitive inhibitor has A no effect on substrate binding B no effect on substrate binding and vice versa C significant effect on substrate binding D significant effect on substrate binding and vice versa

NO EFFECT ON SUBSTRATE BUILDING AND VICE VERSA

The active site of an enzyme differs from an antibody-antigen binding site in that the enzyme active site A contains modified amino acids B catalyzes a chemical reaction C is complementary to a specific ligand D contains amino acids without side chains

CATALYZES A CHEMICAL REACTION

Enzymes are basically A proteins B vitamins C fat D carbohydrate

PROTEINS

Which of the following refers to pseudo steady state ? A d(CE)/dt = 0 B d(Cp)/dt = 0 C d(CES)/dt = 0 D d(Cs)/dt = d(CES)/dt

d(CES)/dt = 0

Most enzymes work by A increasing energy of activation B decreasing energy of activation C not affecting energy of activation D none of the above

DECREASING ENERGY OF ACTIVATION

Which category of enzymes belongs to class 5 in the international classification? A Hydrolases B Isomerases C Oxido-reductases D Cyclase

ISOMERASES

Lock and key theory is based on the compatibility of A enzyme and substrate B enzyme and product C enzyme and enzyme substrate complex D enzyme substrate complex and product

ENZYME AND SUBSTRATE

When an enzyme is functioning at Vmax, the rate of the reaction is limited by A the number of collisions between enzyme and substrate B the number of substrate molecules in the reaction C the concentration of the substrate D the rate at which the enzyme can convert substrate to product

THE RATE AT WHICH THE ENZYME CAN CONVERT SUBSTRATE TO PRODUCT

The equation for the rate of product formation for simple enzyme reaction is given by (Where rmax, maximum reaction rate, Cs substrate concentration, Cp product concentration ES, CES enzyme-substrate concentration) A rp = rmax Cs/(Km+Cs) B rp= rmax CES/(Km+ CES) C rp = rmax Cs/(Km+CES) D rp = rmax Cs/(Km+Cp)

rp = rmax Cs/(Km+Cs)

When [S] = 0.1 *KM, the velocity of an enzyme catalyzed reaction is about: A 0.1 * Vmax B 0.3 * Vmax C 0.5 * Vmax D 0.7 * Vmax

0.1 * Vmax

β-amylase is A endoenzyme B exoenzyme C saccharifying enzyme D both (b) and (c)

EXOENZYME SACCHARIFYIN ENZYME

Juice clarification extraction is facilitated by using A cellulases B amylase C inulinase D lactase

CELLULASES

Lysozyme is naturally present in A egg white B bacteria C tears & milk D all of these

EGG WHITE, BACTERIA, TEARS AND MILK

Enzymes act as antimicrobials A by depriving an organism of a necessary metabolite B by generating a substances toxic to the organism C by attracting a cell wall component D all of the above

ALL A B C

Trichoderma β-glucanase is reported A to stabilize mashing B to convert taste fractions of dextrins to fermentable sugars in beer C to convert starch to dextrin D all of the above

TO STABILIZE MASHING

The bitter taste of the high protein materials is reduced by using A invertase B dectinase C protease D none of these

PROTEASE

Sulphydryl oxidase is used for A discoloration B clarification of images C UHT milk off flavour removal D all of these

UHT MILK OFF FLAVOR REMOVAL

α-amylase is an endo enzyme which requires A Ca B Cu C Mn D None of these

Liquefaction of starch to dextrin is carried out by A α-amylase B cellulase C pectinase D all of these

α-amylase

Which is true about rennet? A It is a mixture of protease chymosin and pepsin B It is a mixture of rennin and pepsin C Both (a) and (b) D none of the above

It is a mixture of protease chymosin and pepsin It is a mixture of rennin and pepsin

Milk digestibility is improved by using A RNase B lactase C β-amylase D none of these

LACTASE

Which of the following mainly serve to convert starch into high fructose corn syrup (HFCS)? A α-amylase B Gluco-isomerase C Gluco-amylase D all of these

α-amylase Gluco-isomerase Gluco-amylase

Lysozyme A catalyses hydrolysis of β-1-4 linkages between N-acetyl muranic acid and N-acetyl glucosamine in peptideoglycan B catalyses hydrolysis of α-1-4 linkages between N-acetyl muranic acid and N-acetyl glucosamine in peptideoglycan C catalyses hydrolysis of α-1-4 linkages between N-diacetyl muranic acid and N-diacetyl glucosamine in peptideoglycan D all of the above

catalyses hydrolysis of β-1-4 linkages between N-acetyl muranic acid and N-acetyl glucosamine in peptideoglycan

Hersperidinase is used for A juice clarification B juice debittering C off flavour reduction D RNA reduction in fish

JUICE CLARIFICATION

Which of the following metallic ion is there in ascorbic acid oxidase? A Mg B Fe C Cu D Mn

Which of the enzyme combination is commercially used for the removal of oxygen? A Glucose oxidase-cellulase B Glucose oxidase-catalase C Glucose oxidase-lactase D All of these

GLUCOSE OXIDASE-CATALASE

The enzyme used to reduce bitterness of grapes commonly contains A α-L-rhamonosidase B β-d-glucosidase C β- galactosidase D both (a) and (b)

α-L-rhamonosidase β-d-glucosidase

Citrus juice debittering can be carried out using A limoninase B inulinase C anthocyanase D None of these

LIMONINASE

Which of the following enzyme is responsible for causing vitamin B deficiency disease beriberi? A Ascorbic acid oxidase B Thiaminase C Lipoxygenase D None of these

THIAMINASE

Soya off flavour removal may be achieved using A di acetyl reductase B β- amylase C aldehyde oxidase D protease

ALDEHYDE OXIDASE

The reduction in off flavour of beer is practiced through A hersperidinase B rnase C invertase D diacetyl reductase

DIACETYL REDUCTASE

Discoloration can be achieved by using A sulphloydryl oxidase B proteases C anthocyanase D all of these

ANTHOCYANASE

The prosthetic group present in phenolase enzyme is A Mg B Cu C Ca D Fe

Enzymes degrade, alter or synthesize a food component through A oxidation/reduction/isomerization B hydrolysis/synthesis C group transfer D all of the above

oxidation/reduction/isomerization hydrolysis/synthesis group transfer

The enzyme β-galactosidase is also known as A lactase B EC3.2.1.23 C both (a) and (b) D isomerase

lactase EC3.2.1.23

Chymosin hydrolyses the bond between A Alanine and glycine B Phenyl alanine and methonine C Glutamic acid and alanine D Alanine and phenyl alanine

PHENYL ALANINE AND METHONINE

The function of the disengagement zone in an airlift fermenter is to A prevent CO2 rich bubbles from entering the downcomer B reduce the velocity of the bubbles C reduce liquid loss as aerosols D all of the above

ALL OF THE ABOVE

Stationary phase is described as A no further increase in the cell population after a maximum value B deceleration of growth and division rate after the growth rate reaches a maximum C acceleration of growth and division rate after the growth rate reaches a maximum D deceleration of growth and division rate after the growth rate reaches a minimum

NO FURTHER INCREASE IN THE CELL POPULATION AFTER MAXIMUM VALUE

In the accelerated phase, cell starts to A increase and the division rate increases to reach a maximum B decrease and the division rate increases to reach a maximum C increase and the division rate decreases to reach a maximum D increase and the division rate increases to reach a minimum

increase and the division rate increases to reach a maximum

The monod model predicts that the specific growth rate A will increase with the concentration of the growth limiting substrate until it reaches a maximum value B will decrease with the concentration of the growth limiting substrate C will increase with the concentration of the growth limiting substrate D does not depend on growth limiting substrate

WILL INCREASE WITH THE CONCENTRATION OF THE GROWTH LIMITING SUBSTRATE UNTIL IT REACHES A MAXIMUM VALUE

A mixed fermentation is one, which produces A both alcohol and carbon dioxide B both acid and carbon dioxide C both acid and alcohol D several different kinds of acid

BOTH ACID AND ALCOHOL

The function of a mechanical seal is to A prevent contaminants entering the reactor B prevent cells from leaving the reactor C both (a) and (b) D prevent air to enter

PREVENT CONTAMINANTS ENTERING THE REACTOR PREVENT CELLS FROM LEAVING THE REACTOR

The phenomenon in which substrates are used in a sequential manner is known as A trans-substrate genesis B dialism C diauxie D multiplicity

DIAUXIE

The dilution rate, D is defined as(where F = volumetric flow rate, VR = total volume of culture in the reactor and μ specific growth rate) A F/VR B VR/F C μ/F D F/μ

F/VR

Diauxie is A growth factors B microbiological die off C the simultaneous uptake of nutrients D the stagewise uptake of nutrients

THE STAGEWISE UPTAKE OF NUTRIENTS

An open system in which the growth rate is maintained by adding a nutrient (present in limiting quantities) at the same rate as that medium containing micro-organisms is removed is called A manostat B chemostat C turbidostat D culturostat

CHEMOSTAT

In the death phase A nutrients available for the cells are depleted and begin to die B the number of viable cells will increase C nutrients available for cells are replenished and start to multiply D none of the above

NUTRIENTS AVAILABLE FOR THE CELLS ARE DEPLERED AND BEGIN TO DIE

The maximum specific growth rate of an organism depends on A medium composition B temperature C pH D All of these

MEDIUM COMPOSITION, TEMPERATURE, PH

Which of the following is not correct for the Monod model and the Michaelis Menten Model? A The Michaelis Menten Model was derived from a curve fitting exercise B The Michaelis Menten model was derived from an analysis of the mechanism of microbial growth C The Monod model was derived from an analysis of the mechanism of microbial growth D All of the above

THE MONOD MODEL WAS DERIVED FROM AN ANALYSIS OF THE MECHANISM OF MICROBIAL GROWTH

Bubble column reactor has A large height to diameter ratio B small height to diameter ratio C large diameter to height ratio D small diameter to height ratio

LARGE HEIGTH TO DIAMETER RATIO

Why a T-flask used in small-scale cell culture is incubated in a horizontal position? A To save space B To increase the surface area of the liquid-air interface C Both (a) and (b) D To increase the rate of oxygen transfer into the liquid

To save space To increase the surface area of the liquid-air interface

An open system in which the growth rate is maintained by the removal and addition of media at such a rate as to maintain a constant cell density is called a A manostat B chemostat C turbidostat D culturostat

TURBIDOSTAT

Wash out in steady state fermentation occurs when A dilution rate is less than maximum specific growth rate B dilution rate is higher than the maximum specific growth rate C cell concentration reaches the maximum D specific growth rate is maximum

DILUTION RATE IS HIGHER THAN THE MAXIMUM SPECIFIC GROWTH RATE

Fermentor should be filled with medium upto A 65-70% B 70-75% C 75-80% D 80-85%

75% TO 80%

Bacterial growth curve is obtained by plotting A number of cells versus time B number fo spores versus time C log of number of cells versus time D log of number of cells survived versus time

LOG OF NUMBER OF CELLS VERSUS TIME

When intracellular enzymes of whole cells are to be used in a bio-conversion process, it is often necessary to____________the cells. A permeabilize B lyophilize C heat-kill D denature

PERMEABILIZE

Heat transfer rates (per unit volume) will be lowest in A Stirred tank bioreactor with biomass recycle B Continuous air lift bioreactor C Continuous packed bed reactor D Continuous fluidized bed bioreactor

CONTINUOUS PACKED BED REACTOR

The function(s) of the draft tube in an airlift bioreactor is A to reduce bubble coalescence B to improve circulation C to even out shear conditions throughout the reactor D all of the above

TO REDUCE BUBBLE COALAESCENCE TO IMPROVE CIRCULATION TO EVEN OUT SHEAR CONDITIONS THROUGHOUT THE REACTOR

The Monod Model relates A substrate utilized with the biomass consumption B specific growth rate to the substrate availability C yield with the biomass utilization D the biomass concentration with specific growth rate

SPECIFIC GROWTH RATE TO THE SUBSTRATE AVAILABILITY

The height to diameter ratio (H/D) for the column fermenters is A <3 B >3 C <1.5 D >1.5

BIOCHEMICAL ENGINEERING Flashcards

(108 cards)