Practice Questions

TLS Online TPP Program

#Question id: 3881

Which one of the following statements about mRNA stability is true?

#Section 3: Genetics, Cellular and Molecular Biology

Degradation always proceeds in the 5' to 3' direction.
Degradation of mRNA by polynucleotide phosphorylase yields 5'-nucleoside monophosphates.
In general, bacterial mRNAs have longer half-lives than do eukaryotic mRNAs.
Secondary structure in mRNA (hairpins, for example) slows the rate of degradation.

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TLS Online TPP Program

#Question id: 15494

#Section 4: Fundamentals of Biological Engineering

Assuming that cells convert two-thirds (w/w) of the substrate to biomass, the stoichiometric coefficient (1 only) for glucose utilisation for the following reaction is

TLS Online TPP Program

#Question id: 15495

#Section 4: Fundamentals of Biological Engineering

Calculate the degree of reduction for following substrates:

TLS Online TPP Program

#Question id: 15496

#Section 4: Fundamentals of Biological Engineering

S. cerevisiae produces ethanol at a yield of 0.5 g/g glucose. The strain ferments 20g/l glucose in 24 hours. Calculate productivity of ethanol in this fermentation

TLS Online TPP Program

#Question id: 15497

#Section 4: Fundamentals of Biological Engineering

A. aceti converts alcohol to acetic acid according to the stoichiometric relation

C₂H₅OH + O₂ 🡪CH₃COOH + H₂O

In a vigorously agitated and aerated reactor containing 20 g/l ethanol, the organism produces 16 g/l acetic acid and 2 g/l was the residual ethanol concentration. What are the theoretical and observed yields of acetic acid expressed in g/g ethanol?

TLS Online TPP Program

#Question id: 15498

#Section 4: Fundamentals of Biological Engineering

The maximum yield for microbial conversion of Glucose (C₆H₁₂O₆) to ethanol (C₂H₅OH) on a mol/mol basis is approximately:

TLS Online TPP Program

#Question id: 15499

#Section 4: Fundamentals of Biological Engineering

Growth yield coefficient of microbes is defined as