Introduction to Balanced Growth

Question 1

represents an approximation where the average cellular synthesis
activities are not affected by the growing cell population as the coordination is relatively
perfect.

Answer 1

Balanced growth kinetics

Question 2

In an environment favorable for growth, cells regulate their metabolism and adjust the rates of various internal reactions so that a condition of_____________ occurs

Answer 2

balanced growth

Question 3

Under balanced growth kinetics, the composition of the biomass remains

Answer 3

constant

Question 4

the cell is able to modulate the effects of external perturbations and keep the biomass composition steady despite changes in environmental conditions.

Answer 4

balanced growth

Question 5

For the biomass composition to remain constant during growth, the specific rate of production of each component in the culture must be equal to the __________

Answer 5

cell specific growth rate, μ.

Question 6

Balanced growth cannot be achieved if environmental changes affect the

Answer 6

rate of growth

Question 7

balanced growth occurs at the same time as

Answer 7

exponential growth

Question 8

In _____________, the progressive doubling of cell number results in a continually
increasing rate of growth in the population.

Answer 8

unicellular organisms

Question 9

A bacterial culture undergoing balanced growth mimics a

Answer 9

first-order autocatalytic chemical
reaction

Question 10

the rate of the cell population increase at any particular time is proportional to the ____________ of bacteria present at that time

Answer 10

number density (CN)

Question 11

The specific growth rate of the cells depends on the _________________ during growth and decline phases of batch culture

Answer 11

concentration of nutrients in the medium

Question 12

a single substrate exerts a dominant influence on the rate of growth

Answer 12

growth-rate limiting substrate or, growth-limiting substrate

Question 13

often the carbon or nitrogen source, although in some cases it is oxygen or another oxidant such as nitrate

Answer 13

growth-limiting substrate

Question 14

the specific growth rate is related to the concentration of the growth limiting substrate by

Answer 14

Monod equation

Question 15

Monod equation is proposed by _____ in ________

Answer 15

French biochemist Jacques Monod in 1942

Question 16

this ________ type of equation was used to relate the growth rate of a microorganism culture to the prevailing feed concentration.

Answer 16

saturation isotherm

Question 17

one of the most widely employed expressions for the effect of substrate concentration on specific growth rate

Answer 17

Monod equation

Question 18

an empirical expression based on the form of
equation normally associated with enzyme kinetics or gas adsorption.

Answer 18

Monod equation

Question 19

Monod equation has same form as the rate equation for an enzyme catalyzed reaction _________ and ________

Answer 19

Michaelis-Menten equation, Langmuir adsorption isotherm:

Question 20

intrinsic parameters of the cell-substrate system

Answer 20

𝜇𝑚𝑎𝑥 and 𝐾s

Question 21

According to the Monod equation, further increase in the nutrient concentration after 𝜇 reaches 𝜇𝑚𝑎𝑥 __________

Answer 21

does not affect the specific growth rate

Question 22

Typical values of 𝐾𝑆 are very small of the order of ________for carbohydrate substrates and
___________ for other compounds like amino acids

Answer 22

mg per liter, 𝜇𝑔 per liter

Question 23

The concentration of the growth-limiting substrate [S] in culture media is normally ________ than 𝐾s

Answer 23

much greater

Question 24

_____ is assumed to be insignificant

Answer 24

𝐾𝑆

Question 25

___________ and ____________ as long as S remains greater than about ____, which is usually for most of the culture period

Answer 25

𝜇 ≈ 𝜇𝑚𝑎𝑥 and growth follows exponential kinetics, 10 𝐾S

Question 26

most frequently used expression relating growth rate to substrate concentration

Answer 26

Monod equation

Question 27

Monod equation is valid only for _________ and should not be applied when growth conditions are changing rapidly.

Answer 27

balanced growth

Question 28

At __________ levels, the Monod equation has limited applicability

Answer 28

low substrate

Question 29

When growth is inhibited by ___________, extra terms can be added to the Monod equation to account for these effects.

Answer 29

high substrate or product concentrations

Question 30

Alternative equations to Monod equation

Answer 30

Blackman equation, Tessier Equation, Moser equation, Contois equation

Question 31

This refers to the metabolic needs of a cell to stay viable by consuming nutrients or converting intercellular materials

Answer 31

Endogenous Metabolism

Question 32

During the _________, the cell catabolizes cellular reserves for new building blocks and for energy-producing monomers

Answer 32

stationary phase

Question 33

an extension of the Monod model which gives way for a maintenance energy

Answer 33

Cell Maintenance

Question 34

recognizes that generated energy by substrate consumption is not solely used in cell growth, but also in different functions

Answer 34

Cell Maintenance

Question 35

represents the amount of substrate diverted from growth

Answer 35

𝑚 = specific maintenance rate

Question 36

Other related forms of specific growth rate dependence

Answer 36

Tessier, Moser, and Contois

Question 37

A model that describes the specific growth rate as a function of continuous substrate concentration.

Answer 37

Tessier Model

Question 38

A model based on substrate concentration only

Answer 38

Moser Model

Question 39

A model based on both substrate and biomass concentration.

Answer 39

Contois Model -

Question 40

saturation constant

Answer 40

Ks

Question 41

For Monod, the constants for the differential equation, a,b,k

Answer 41

0 2 1/𝐾𝑠

Question 42

For Tessier, the constants for the differential equation, a,b,k

Answer 42

0 1 1/K

Question 43

For Moser, the constants for the differential equation, a,b,k

Answer 43

1 −1/𝑛 1 +1/𝑛 1/(𝐾𝑠^(1/n))

Question 44

For Contois,the constants for the differential equation, a,b,k

Answer 44

0 2 1/𝐾𝑆x

Question 45

binds to the active site and prevents the substrate from binding there

Answer 45

competitive inhibitor

Question 46

binds to a different site on the enzyme; it doesn't block substrate binding, but it causes other changes in the enzyme so that it can no longer catalyze the reaction efficiently

Answer 46

noncompetitive inhibitor

Question 47

There are two main types of mathematical models of growth kinetics

Answer 47

structured and unstructured

Question 48

simplest types of product formation kinetics arise when there is a simple stoichiometric connection between product formation and substrate utilization or cell growth

Answer 48

Unstructured models (UKM)

Question 49

represent, from a simple global point of view, the metabolic behavior of biomass cell production

Answer 49

Unstructured models (UKM)

Question 50

In unstructured models, products are categorized into various types based on their relationship with microbial growth

Answer 50

Growth-associated products followed by Non-growth- associated products and Mixed-mode product formation.

Question 51

The product is formed along with the growth of the microbial cells and product concentration is almost directly proportional to microbial growth rate

Answer 51

growth-associated products

Question 52

Formed by growing cells and hence primary metabolites

Answer 52

Growth-linked products

Question 53

In growth associated, That is product concentration __________with cell concentration

Answer 53

increases

Question 54

In _____________, product formation is nowhere related to the growth rate of microbial cells but it’s a function of cell concentration and we can say that product formation and microbial growth rate are almost ___________to each other

Answer 54

non-growth associated products, inversely proportional

Question 55

In many fermentations, especially those involving ___________, significant product formation does not occur until relatively late in __________, perhaps approaching or into the stationary phase.

Answer 55

secondary metabolites, batch cultivation

Question 56

Fermentation of _________ follows the non-growth associated product

Answer 56

penicillin

Question 57

In mixed mode, The product formation from the microorganism depends on both ____________

Answer 57

growth and non-growth associated

Question 58

It takes place during growth and stationary phases

Answer 58

Mixed-mode

Question 59

Mixed-mode is evident, especially in the

Answer 59

Leudeking Piret Model.

Question 60

empirical relationship widely used to evaluate specific production rates of some metabolites or other products in cultured cell

Answer 60

Leudeking Piret Model.

Question 61

Leudeking Piret model is developed in _______ for ________ production in batch and continuous culture

Answer 61

1959, lactic acid

Question 62

has proved extremely useful and versatile in fitting product formation data from many different fermentations

Answer 62

Leudeking Piret kinetics

Question 63

This is the expected kinetic form when the product is the result of energy-yielding metabolism, as in several anaerobic fermentations

Answer 63

Leudeking Piret kinetics

Question 64

The values of 𝛼 and 𝛽 in _____________ determine the product formation kinetics of the cell.

Answer 64

Leudeking Piret kinetics

Question 65

If 𝛼 = 0, the product is

Answer 65

non-growth associated

Question 66

If 𝛽 = 0, the product is

Answer 66

growth-associated

Question 67

If 𝛼 ≠ 0 and 𝛽 ≠ 0, the product is

Answer 67

mixed growth associated

Question 68

introduced a classification of many of these possibilities which serves to illustrate some possible cases

Answer 68

F. H. Deindoerfer

Question 69

Deindoerfer’s classification of fermentation patterns

Answer 69

simple, simultaneous, consecutive, stepwise

Question 70

Nutrients converted to products in a fixed stoichiometry without accumulation of intermediates

Answer 70

Simple reactions

Question 71

Nutrients converted to products in a variable stoichiometry without accumulation of intermediates.

Answer 71

Simultaneous reaction

Question 72

Nutrients converted to a product with an accumulation of an intermediate

Answer 72

Consecutive reactions

Question 73

Nutrients completely converted to intermediate before conversion to product, or selectively converted to product in preferential order.

Answer 73

Stepwise reactions

Question 74

Two important guidelines in writing structured product formation kinetics model

Answer 74

1. all reactions should be expressed in terms of intrinsic concentrations

Question 75

amount of a compound per unit cell mass or cell volume

Answer 75

intrinsic concentration

Question 76

amount of a compound per unit reactor volume

Answer 76

extrinsic concentration

Question 77

____________ concentrations cannot be used in kinetic expressions

Answer 77

Extrinsic

Question 78

Synthesis of several microbial antibiotics and other secondary metabolites is inhibited by

Answer 78

high concentrations of phosphate.

Question 79

The more accurately a kinetic description describes the actual chemical events that occur, the __________the kinetic model

Answer 79

more robust

Question 80

the model is more likely to produce good results when applied to conditions other than those used to evaluate the model and determine its parameters

Answer 80

Robust

Question 81

process by which cells make proteins.

Answer 81

Protein synthesis

Question 82

Two stages of protein synthesis

Answer 82

transcription and translation

Question 83

the transfer of genetic instructions in DNA to mRNA in the nucleus

Answer 83

Transcription

Question 84

Three steps under transcription

Answer 84

initiation, elongation, and termination.

Question 85

After the mRNA is processed, it carries the instructions to a _____________ in the cytoplasm.

Answer 85

ribosome

Question 86

Translation occurs at

Answer 86

ribosome

Question 87

Assuming balanced growth, the rate of mRNA synthesis and rate of protein synthesis are both

Answer 87

zero

Question 88

To account for gene transcription modulation by an operator system, the __________ is introduced

Answer 88

promoter utilization efficiency

Question 89

The rate of synthesis is proportional to the _________ and _________ with which this mRNA is utilized at the ribosomes

Answer 89

concentration of mRNA coding for the protein and the efficiency

Question 90

are those whose cells are not separated following cell division and so tend to grow in the form of 'filaments

Answer 90

Filamentous organisms

Question 91

Example of filamentous organisms

Answer 91

molds

Question 92

often form microbial pellets at high cell densities in suspension culture

Answer 92

Filamentous organisms

Question 93

The growth models of molds should include the ___________ and consumption of nutrients within the pellet at large pellet sizes.

Answer 93

simultaneous diffusion

Question 94

can grow on the surface of a moist solid

Answer 94

filamentous cells

Question 95

common example of kinetics of product formation and substrate utilization of molds and those of other filamentous microbes

Answer 95

Penicillin batch fermentation

Question 96

For ___________ in a fixed batch time, there is an optimal initial substrate concentration

Answer 96

maximum product yield

Question 97

When there is an abundance of substrate, _______ occurs

Answer 97

fast fermentation

Question 98

little product is formed and the substrate is primarily used for biomass production

Answer 98

fast fermentation

Question 99

By minimizing branching in actively growing hyphae in the inoculum, product formation is __________.

Answer 99

maximized

Question 100

The__________ the degree of branching, however, the longer the lag phase and thus the required batch time

Answer 100

smaller

Question 101

substantially capable of predicting product formation

Answer 101

kinetic model of cell growth

Question 102

Cell populations are typically _________with respect to individual cell size, age, growth rates, and other properties

Answer 102

heterogeneous

Question 103

The major disadvantage of ______________ models is their mathematical complexity

Answer 103

segregated kinetic

Question 104

Cell division ___________ result in the production of two viable progeny.

Answer 104

does not always

Question 105

if 𝛩 is ___________ then doubling time for a single cell is less than overall doubling time

Answer 105

not zero

Question 106

may be used to calculate other frequency functions and average population properties with direct physical significance

Answer 106

age density function

Question 107

Single cells may increase in mass while the total mass of the cell population increases

Answer 107

exponentially

Question 108

The volume distribution which could be measured experimentally using a

Answer 108

Coulter counter or light-scattering flow cytometry measurements

Question 109

Expresses the specific product formation rate by cells that have spent a total time θ in the reactor by ∑ 𝐴𝑖𝑒 𝑞 −𝑘𝑖θ 𝑖=1 .

Answer 109

product formation model of Ping Shu