BIOCHE QUIZ Flashcards
What kind of reactions require a suitable
substrate and operating
conditions such as
temperature, pH, etc.
Enzymatic reactions
In enzymatic reactions, what does an enzyme require?
a suitable substrate
suitable operating conditions such as (pH and Temperature)
Living cells require _____ and different operational parameters (5) for growth and product formation
Proper medium
pH
Temperature
CO2
O2
Humidity
The liquid medium contains the
following ingredients
Carbon Source
Nitrogen Source
Minerals and Vitamins
used for cell growth, product formation,
energy source, and maintenance
Carbon Source
mostly contributes to the growth of cells
Nitrogen Source
mostly used as cofactors in the
metabolic pathways of living cells
Mineral and Vitamins
Cell growth is monitored in two ways:
number of viable cells/volume or mass of cells/volume
mass/volume
the mass of living cells is
proportional to the number of cells
Unicellular organisms
the size and density of the
cells are not necessarily proportional to their numbers
Mold growth
The concentration of the cells may be expressed in either the number
of viable cells/volume or the mass of cells/volume.
Unicellular organisms
Processes associated with cell
growth
- Utilization of Materials from the medium by the cells
- Generation of metabolic end products in the medium
The concentration of mold-like cells is expressed only in the
mass/volume.
Mold growth
Kinetics of the Biochemical processes involved for cell growth and metabolism
Medium Environment
Cell Population
Under Medium environment
Multicomponent
Reactions in Solution
Acid-base equilibria
Variable pH and Temperature
Changing rheological properties (density and viscosity)
Multiphase
Under Cell population
Cell to cell heterogeneity
Chain reactions
Internal Control
Adaptability
Stochastic
Genetic change
T/F: It is impractical to consider a kinetic model that has all the features mentioned.
T
Approximations to develop a useful representation of cell growth kinetics
concentration of all components
present in the medium is sufficiently high and the rate of
reaction depends on the concentration of that
component only
process parameters are regulated by controlling
the environmental parameters such as pH, temperature,
and dissolved oxygen concentration
It is necessary to simplify the model with
some _______ and develop a useful
representation of cell growth kinetics.
approximation
Example of a component that must be sufficiently high since the rate of reaction depends on its concentration
rate-limiting substrate
Who classified the
microbial systems according to
the number of components
used in the cellular
representation
Arnold Fredrickson and Henry
Tsuchiya
usually deals with the
kinetics of the change in
individual components
present in the cells
Structured model
Examples of Structured model
RNA, DNA, proteins
considered a single component system assuming
the kinetic changes of all
components is same.
Unstructured
the kinetics of individual
cells is taken into
consideration separately
Segregated model
the growth
characteristics of individual
cells are assumed to be the
same.
Unsegregated
When cell growth kinetics is assumed to be unsegregated, unstructured models, it is?
Ideal
the reaction mixture usually
consists of a substrate, and enzyme, and a cofactor
Enzymatic reaction
The reaction normally takes place at a particular temperature
and pH.
Enzymatic reaction
The substrate is specific with respect to the enzyme
Enzymatic reaction
one substrate (carbon source)
present in the medium can produce different products with
the help of different microorganisms
Microbial reaction
In special cases, the same microorganism can produce
different products from the same substrate
Microbial reaction
produces citric acid when the pH is allowed to change
during the fermentation process
Aspergillus niger
Aspergillus niger produces ____ when the pH is controlled at 6.0
gluconic
acid
Usually globular proteins with an active site that catalyzes a specific reaction
Enzymatic reactions
Each enzyme require a specific substrate
Enzymatic reactions
Phases of Bacteria Growth cycle
Lag phase
Log phase
Stationary Phase
Death phase
Also called acclimitization phase
Lag phase
Individual bacteria becomes mature
and cannot divide
Lag phase
RNA, enzymes, and other molecules
undergo syntheses.
Lag Phase
This phase can last from one hour to
several days
Lag Phase
Cells are active
Log Phase
plays an
important role in the fermentation
process.
Age of inoculums
The age of inoculums plays an
important role in the fermentation
process.
Log phase
The number of new bacteria produced
per unit time is proportional to the
present population
Log Phase
A substance used for inoculation or the introduction of pathogens or antigen into a living organism to stimulate the production of antibodies
Inoculum
Where are the most suitable phases for fermentation?
Mid-lag phase
Late-log phase
A straight line will be obtained by
Log of cell mass (X) against
Time
Slope of ln X Vs Time gives
specific growth rate (ug)
Measure of the number of divisions per cell unit time in the case of unicellular cells
Specific growth rate
The rate of microbial growth is characterized by?
Specific growth rate
Is the difference between the gross specific growth rate and rate of cell death
u net
Is also called starvation phase
Stationary phase
Characterized by depletion of essential nutrient or formation of inhibitory products like organic acids
Stationary phase
Rate of cell growth= rate of cell death
Stationary phase
Mutations can occur
Stationary phase
Secondary metabolites are formed
Stationary phase
Secondary metabolites are formed
Stationary phase
Death of bacteria mostly due to
Lack of nutrients
Environmental temperature above or below the tolerance limits for the species
Other injurious conditions
Three processes for microbial fermentation
Batch
Fed batch
Continuous
It is difficult to obtain useful kinetic information on microbial populations from reactors in nonuniform condition T/F
T
Where does the study of kinetics is necessarily done?
Well-mixed reactors
Where should the detailed analysis of cell growth kinetics be performed?
Batch and continuous stirred-tank reactors
Several biochemical processes are carried out to study cell growth in ?
Batch process
Generally prepared by using seed culture in a liquid medium
Inoculum
The concentrations of nutrients, cells, and products vary with time as cell growth takes place
Batch reactor
Microbial biomass and product formation can be represented by
Substrate+Microbial cells = Extracellular Products + More Microbial cells
The rate of formation depends on
Characteristics of the cell population (composition, morphology and age distribution)
All environmental parameters that influence the rate of reactions in the cells and the medium
Growth achieves it’s maximum rate
Log phase
Growth ceases due to starvation
Stationary phase
Cell losses viability and lyse
Death phase
SGR of Lag phase
0
SGR of Log
Maximum
SGR of Stationary phase
0
SGR of death phase
Less than 0
What can be developed in the case of batch process
Bacterial cell growth cycle
Batch process is an _____ operation
Unsteady state
Operation where the concentration of cell mass and substrate change with time
Unsteady state
What growth stated that The log phase remains approximately constant approaches maximum specific growth rate?
Batch growth
Time required for doubling the microbial mass
Doubling timd
Time required between cell divisions
Generation time
Like specific growth rate, these 2 can be expressed as is
Specific substrate consumption rate and specific product formation rate
Describes cell growth model like Michaelis -Menten Equation, which describes enzymatic reaction
Jacques Monod
This equation is considered an ideal equation like unstructured, unsegregated model
Jacques Monod
Limitations of Monod Model
When limiting substrate concentration approaches infinity, the specific growth rate approaches maximum
Specific growth rate is finite when limiting substrate concentration is finite
Does not explain what will happen when limiting substrate concentration approaches zero
Does not take care of cell death
Not applicable in the case of substrate and product inhibitions
Other substrate -limited growth models as alternative to Monod equation
Blackman Equation
Tessier Equation
Moser Equation
Contois Equation
Very much resembles Monod equation where saturation constant depends on the cell mass concentration
Contois Equation
Types of inhibitions
Substrate inhibition
Product inhibition
Inhibition by Toxic compounds
T/F: the inhibition pattern of microbial growth is analogous to the inhibition of enzymatic reaction
T
In cell growth inhibition the kinetic constants are obtained from Experimental data by?
curve fitting
At high substrate concentrations, the microbial growth rate is inhibited by the higher substrate concentration
Substrate inhibition
May be alleviated by a slow, intermittent addition of substrate to the growth medium
Substrate inhibition
The substrate inhibition for cell growth may either be ___ and ____
Competitive or non-competitive
High product concentration can be inhibitory for microbial grot
Product inhibition
T/F: product inhibition could also be competitive or non-competitive
T
Analogous to enzyme inhibition
Toxic compound inhibition
Has competitive, non-competitive and uncompetitive inhibition
Toxic compound inhibition
Characterizes cell growth in terms of carrying capacity that can be obtained
Logistic equation
It does not consist of Substrate concentration
Logistic equation
Independent of substrate
Logistic equation
Only related to biomass concentration
Logistic equation
Cell growth is directly proportional to biomass concentration and the carrying capacity
Logistic equation
Is related to biomass concentration and limiting substrate concentration
Monod equation
Does not consider more than one growth - limiting substrate concentration
Monod equation
Forms microbial pellets at high cell densities in suspension culture
Filamentous organisms like mold
Cells growing inside pellets are subjected to
Diffusional limitations
In the absence of ____, the radius of pellet in the submerged culture ________ with time
Mass transfer, increases linearly
Considered to correlate the rate of product formation other than cell mass with cell growth rate
Luedeking-Piret model
It combines growth associated and non growth associated product formation
Luedeking-Piret model
If alpha is equal to zero
Product is non-growth associated
If beta is equal to zero
Product growth is associated
If alpha and beta are not equal to zero
Mixed growth associated
Examples of growth associated products
Ethanol and enzymes
Examples of non-growth associated
Antibiotics such as penicillin, streptomycin
Example of mixed-associated
Lactic acid fermentation
In this, A part of the substrate contributes to cell maintenance
Cell growth
Deals with maintenance of cells
Pirt model
Deals with maintenance of cells
Pirt model
