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
  1. Degradation always proceeds in the 5' to 3' direction.

  2. Degradation of mRNA by polynucleotide phosphorylase yields 5'-nucleoside monophosphates.

  3. In general, bacterial mRNAs have longer half-lives than do eukaryotic mRNAs.

  4. Secondary structure in mRNA (hairpins, for example) slows the rate of degradation.

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TLS Online TPP Program

#Question id: 19485

#Section 4: Fundamentals of Biological Engineering

The growth of S.cerevisiae on glucose under anaerobic conditions can be described by the following reaction:
C6H12O6 + aNH3 → 0.59 CH1.64N0.16O0.52 (biomass) + 0.43 C3H8O3 + 1.54CO2 + 1.3C2H5OH +0.036H2O
Determine the biomass (MW= 23.74) yield coefficient Yx/s

TLS Online TPP Program

#Question id: 19486

#Section 4: Fundamentals of Biological Engineering

The growth of S.cerevisiae on glucose under anaerobic conditions can be described by the following reaction:
C6H12O6 + aNH3 → 0.59 CH1.64N0.16O0.52 (biomass) + 0.43 C3H8O3 + 1.54CO2 + 1.3C2H5OH + 0.036H2
and determine the product yield coefficient Y etoh/s and determine coefficient a.

TLS Online TPP Program

#Question id: 19487

#Section 4: Fundamentals of Biological Engineering

What is the yield coefficient if the initial substrate concentration is 20 g/l and biomass is 0.2 g/l. The substrate is then consumed and produces 6.0 g/l of biomass?

TLS Online TPP Program

#Question id: 19488

#Section 4: Fundamentals of Biological Engineering

What is the yield coefficient if the initial substrate concentration is 10 g/l and biomass is 0.1 g/l. The substrate is then consumed and produces 5.3 g/l of biomass?

TLS Online TPP Program

#Question id: 19489

#Section 4: Fundamentals of Biological Engineering

The yield coefficient is not used in growth kinetic relationship of which of the following growth kinetics?

TLS Online TPP Program

#Question id: 19530

#Section 4: Fundamentals of Biological Engineering

If air consists of 77% by weight of nitrogen and 23% by weight of oxygen calculate:
(i) the mean molecular weight of air,
(ii) the mole fraction of oxygen,
(iii) the concentration of oxygen in mole/m3 and kg/m3  if the total pressure is 1.5 atmospheres and the temperature is 25 °C.