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TLS Online TPP Program

#Question id: 4337

Which of the following conditions is most likely to cause the lactose operon to be transcribed?

#Section 3: Genetics, Cellular and Molecular Biology

  1. There is more glucose in the cell than lactose.

  2. There is glucose but no lactose in the cell.

  3. The cyclic AMP and lactose levels are both high within the cell.

  4. The cAMP level is high and the lactose level is low.

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TLS Online TPP Program

#Question id: 14398

#Section 5: Bioprocess Engineering and Process Biotechnology

The internal effectiveness factor is useful because , which statement is not correct 
TLS Online TPP Program

#Question id: 14399

#Section 5: Bioprocess Engineering and Process Biotechnology

 observable Thiele modulus CD decreases when 
TLS Online TPP Program

#Question id: 14400

#Section 5: Bioprocess Engineering and Process Biotechnology

internal mass transfer effects are eliminated when the internal effective ness factor is 
TLS Online TPP Program

#Question id: 14401

#Section 5: Bioprocess Engineering and Process Biotechnology

Denitrifying bacteria are immobilised in gel beads and used in a stirred reactor for removal of nitrate from groundwater. At a nitrate concentration of 3 g m -3, the conversion rate is 0.011 g s-1 m-3 catalyst. The effective diffusivity of nitrate in the gel is 1.5 × 10 -9 m 2 s-1, the beads are 6 mm in diameter, and the liquid-solid mass-transfer coefficient is 10 -5 m s-1. Km for the immobilised bacteria is approximately 25 g m -3. Calculate the observable Thiele modulus with CAs = 1.9 g m -3

TLS Online TPP Program

#Question id: 14402

#Section 5: Bioprocess Engineering and Process Biotechnology

Baby hamster kidney cells are immobilised in alginate beads. The average particle diameter is 5 mm. Rate of oxygen consumption at a bulk concentration of 8 x 10 ^-3 kg 0 2 m ^-3 is 8.4 x 10 ^-5 kg s^- 1 m^-3 catalyst. The effective diffusivity of oxygen in the beads is 1.88 x 10^ -9 m 2 s^- 1. Assume that the oxygen concentration at the surface of the catalyst is equal to the bulk concentration, and that oxygen uptake follows zero-order kinetics. calculate the observable Thiele modulus. 
TLS Online TPP Program

#Question id: 14403

#Section 5: Bioprocess Engineering and Process Biotechnology

Invertase is immobilised in ion-exchange resin of average diameter 1 mm. The amount of enzyme in the beads is measured by protein assay as 0.05 kg m ^-3. 20 cm ^3 beads are packed into a small column reactor; 75 ml sucrose solution at a concentration of 16 mM is pumped rapidly through the bed. In another reactor an identical quantity of free enzyme is mixed into the same volume of sucrose solution. Assume the kinetic parameters for free and immobilised enzyme are equal: K,,, is 8.8 mM and the turnover number is 2.4 x 10 gmol glucose (g enzyme)-'s^-1. The effective diffusivity of sucrose in the ion-exchange resin is 2 x 10^-6cm2s 4. What is the rate of reaction by free enzyme?