Biochemical Miscellaneous
- Choose the correct completion of the following statement.
A fermenter sterilisation in situ is less efficient than continuous heat sterilisation because
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It uses longer heating time during which heat is lost.
Correct Option: B
It uses longer heating time during which heat is lost.
- In secondary metabolism two distinct phases- trophophase and idiophase refer respectively to
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In secondary metabolism two phases are apparent: trophophase and idiophase. Trophophase is the growth phase of the culture; idiophase is the time when the secondary metabolites are formed. The success of the idio-phase is dependent on the trophophase.
Correct Option: A
In secondary metabolism two phases are apparent: trophophase and idiophase. Trophophase is the growth phase of the culture; idiophase is the time when the secondary metabolites are formed. The success of the idio-phase is dependent on the trophophase.
- A bacterial culture with an approximate biomass composition of CH1.8O0.5N0.2 is grown aerobically on a defined medium containing glucose as the sole carbon source and ammonia being the nitrogen source. In this fermentation, biomass is formed with a yield coefficient of 0.35 gram dry cell weight per gram of glucose and acetate is produced
with a yield coefficient of 0.1 gram acetate per gram of glucose. The respiratory coefficient for the above culture will be
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Yx/s = 0.35 g/g , YP/S = 0.1 g acetate g dry cell g glucose g glucose
The respiratory coefficient Respiratory quotient = Moles of CO2 formed Moles of CO2 consumed = 5 = 1.01 4.95
C6 H12 O6 + b NH3 + O2 → CH1.8O0.5 N0.2 + eH2O + f CO2
C : 6a = 1 + f ...(1)
H : 12a + 3b = 1.8 + 2e ...(2)
O : 6a + 2d = 0.5 + e + 2F ...(3)
b = 0.2
N : b = 0.2
∴ 12a = 1.2 + 2e
6a = 1 + F
Let if a = 1, i.e. F = 5
e = 5.4
d = 4.95
b = 0.2
a = 1
Correct Option: B
Yx/s = 0.35 g/g , YP/S = 0.1 g acetate g dry cell g glucose g glucose
The respiratory coefficient Respiratory quotient = Moles of CO2 formed Moles of CO2 consumed = 5 = 1.01 4.95
C6 H12 O6 + b NH3 + O2 → CH1.8O0.5 N0.2 + eH2O + f CO2
C : 6a = 1 + f ...(1)
H : 12a + 3b = 1.8 + 2e ...(2)
O : 6a + 2d = 0.5 + e + 2F ...(3)
b = 0.2
N : b = 0.2
∴ 12a = 1.2 + 2e
6a = 1 + F
Let if a = 1, i.e. F = 5
e = 5.4
d = 4.95
b = 0.2
a = 1
- A culture of bacteria is infected with bacteriophage at a multiplicity of 0.3. The probability of a single cell infected with 3 phages is
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Probability of bacteria getting infected by a single bacteriophage= 0.3 i.e. P(A)= 0.3
Given, 3 phages, So, probability of bacteria getting infected by 3 phages= P(A) * P(B) * P(C)
= 0.3 * 0.3 * 0.3 = 0.027Correct Option: D
Probability of bacteria getting infected by a single bacteriophage= 0.3 i.e. P(A)= 0.3
Given, 3 phages, So, probability of bacteria getting infected by 3 phages= P(A) * P(B) * P(C)
= 0.3 * 0.3 * 0.3 = 0.027
- In a chemostat operating under steady state, a bacterial culture can be grown at dilution rate higher than maximum growth rate by
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Chemostat is operated by supplying an essential growth limiting nutrient at a constant rate with the result that the culture density and growth rate adjust themselves to the supply.
At steady state,
dx / dt = 0 Therefore, μ = D
This equation shows that by simply varying the medium supply rate the growth rate can be varied.This equation holds true if μ eD or μ–D = positive.
Here, Dc = μmax, i.e. the critical dilution rate is defined as the lowest dilution rate at which washout occurs.
Thus, for a bacterial culture to grow at dilution rate higher than maximum growth rate, the partial cell recycling is needed under steady state condition. Correct Option: A
Chemostat is operated by supplying an essential growth limiting nutrient at a constant rate with the result that the culture density and growth rate adjust themselves to the supply.
At steady state,
dx / dt = 0 Therefore, μ = D
This equation shows that by simply varying the medium supply rate the growth rate can be varied.This equation holds true if μ eD or μ–D = positive.
Here, Dc = μmax, i.e. the critical dilution rate is defined as the lowest dilution rate at which washout occurs.
Thus, for a bacterial culture to grow at dilution rate higher than maximum growth rate, the partial cell recycling is needed under steady state condition.
