⚗️ Biochemical Engineering Solved MCQs with Answers

Practice 513 approved ⚗️ Biochemical Engineering questions with verified answers from the 🧬 Medical Science subject for Pakistan exams.

513 solved MCQs

The Komologorov eddy sizeAnswer: Decreases with stirrer speed Pluronic F68 protects mammalian cells from damage stems as it is a/anAnswer: Surface active agent which stabilizes foams Reynolds number for turbulent flow over a plate should be more thanAnswer: 10⁶ Swirling and vortex formation can be prevented byAnswer: Both (a) and (b) Power number is expressed asAnswer: P0 / N³Dᵢ⁵ρ The power consumption in a stirring vessel can be assessed by using aAnswer: All of these Surface renewal theory predicts that the mass transfer coefficient isAnswer: Directly proportional to the square root of the molecular diffusivity The oxygen transfer rate in a bioreactor will increase ifAnswer: Detergent like molecules are added Which of the following impellers are used for wide range of viscosities?Answer: Turbines Which of the following type(s) of stirrer can be used for microbiological processes?Answer: All of these The range of width for the baffle in the fermenter is __________ times of vessel diameterAnswer: 1/10 to 1/12 The average concentration of oxygen in the boundary layers surrounding the bubbles (C₀*) in a reactor is normally determined byAnswer: Measuring the steady state concentration of oxygen in the bulk liquid prior to inoculation of the reactor Why vortexing is undesirable in the agitation of biological systems?Answer: All of these The rate limiting step in the movement of oxygen from the gas phase in a bubble to the cell is the movement of oxygen molecules throughAnswer: Bubble boundary layer Penetration theory assumes that turbulent eddies travel from the bulk of the phase to the interface where they remain constant for a constant exposure time (tₑ). The model correlatingKₗ, mass transfer coefficient and Dₐᵦ, diffusivity can be expressed asAnswer: Kₗ = 2(Dₐᵦ/πtₑ)⁰․⁵ The oxygen uptake requirements of a microbial population is characterized by the following parameters: μm = 0.2 h⁻¹, K₀ = 0.2 mg O₂.l⁻¹, Y₀ = 0.5 mg dry weight/mg O₂ and C₀,꜀ᵣᵢₜ=0.8 mg.l⁻¹ The required concentration of cells is 1000 mg.l⁻¹ and the saturation oxygen concentration of the medium is 5.8 mg.l⁻¹. The required Kₗ a must be greater thanAnswer: 64 h⁻¹ Which have the maximum resistance while transferring carbon dioxide from the bulk liquid to an air bubble?Answer: Moving through the bubble boundary layer If liquid density and viscosity remains constant, then the Reynolds number in a stirred tank reactor will vary with theAnswer: Square of the impeller diameter What is the ratio of depth of liquid in vessel to the diameter of tank (H:Dₜ)?Answer: 1 : 1 Radial flow impellersAnswer: Both (a) and (b) Transient flow range of mixing speed is obtained forAnswer: 10<Reᵢ<10⁴ A typical ceiling fan would be best described as a(n)Answer: Axial flow impeller What is the ratio of diameter of impeller to the diameter of tank (Dₐ:Dₜ)?Answer: 1 : 3 The reason of using a flat disk in a Turbine isAnswer: To ensure that the bulk of the energy consumption occurs at the blades Which of the following is not considered among the three best-known theories of interphase mass transfer?Answer: Calderbank and Moo-Young theory Which of the following is most likely to cause an increase in the rate of oxygen transfer into a particular aerated fermentation system?Answer: Increase in stirrer speed At 25°C, the saturation concentration of oxygen in water is 1.26 mmol/l and the partial pressure of oxygen is 1 atm. The Henry's law constant will beAnswer: 0.793atml/mmol Gas hold up, characterizing the hydrodynamics in a fermenter, mainly depends on theAnswer: Both (a) and (b) Turbine impeller consists of flat impeller blades withAnswer: A vertical pitch welded to a horizontal disk An aerated bioreactor will increase oxygen transfer rates with the addition of detergents because itAnswer: Discourages bubble coalescence