⚗️ 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 production of an amylase from starch by Aspergillus niger is often performed in a fed batch fermenter. This is due to the reason thatAnswer: Fed-batch reactor can be used to minimize starch concentrations and thus reduce the viscosity of the medium The fastest route of NADH reoxidation isAnswer: Fermentation In fed batch bioreactor modelling, the rate of change in the bioreactor volume is assumed to be equal toAnswer: Flow rate Monoclonal antibodies are typically produced in fed batch reactors becauseAnswer: Hybridoma cells yield higher lactate at high glucose concentrations In plug flow tubular reactor the axial velocity profile on cross-section will beAnswer: Constant Production of organic acids in batch culture is generally growth associated phase followed by non-growth associated production. The probable reason for this is thatAnswer: Organic acids uncouple catabolism from anabolism The concentration of biomass in a continuous stirred tank reactor is 20 g dry weight per litre. What would be the concentration of biomass in the effluent?Answer: Approximately 20 g dry weight per litre The ideal tubular-flow fermenter without radial variations is called aAnswer: Plug flow fermenter Pseudo-steady state in a continuous reactor refers to a reactor in whichAnswer: Concentration oscillate around a mean value The toxicity of organic acids to cellsAnswer: Enhances as the pH falls Which of the following is best described as secondary metabolite?Answer: Penicillin A microorganism which is subjected to the Crabtree effect is most likely toAnswer: Ferment in the presence of high concentrations of sugar and dissolved oxygen When the product formation is approximately equal to the rate of cell growth, the pattern of product formation is termed asAnswer: Growth associated Which of the following would be correct concerning the concentration of biomass (X). growth limiting substrate (S) and product (P) in a chemostat when the cells have been washed out?Answer: X and P will be zero while S is equal to the substrate concentration in feed Pseudomonas aeruginosa has a maximum specific growth rate of 0.8 h⁻¹ in a medium with glucose as a growth limiting substrate. To prevent wash out, the dilution rate must be set toAnswer: less than 0.8 h⁻¹ Saccharomyces cerevisiae when grown in high glucose concentration medium, the cells activity depends on which of the following?Answer: No effect of dissolved oxygen Continuous culture has an advantage over to a batch cultures asAnswer: All of these In the batch-fed mode, substrate will be addedAnswer: Only at the end of the fermentation process When Escherichia coli grow in a well aerated medium, which of the following will occur?Answer: Fructose di-phosphate accumulation inside the cells leading to fermentation An internal draft tube is preferrred to an external draft tube becauseAnswer: It is easier to clean and sterilize a reactor A functional relationship between the specific growth rate and essential compounds concentration was proposed by Monod inAnswer: 1942 The optical density sometimes drops during the lag phase becauseAnswer: Cells tend to grow without dividing leading to a decrease in the surface area to volume ratio The application of just in time (JIT) manufacturing techniques in biotechnology is important becauseAnswer: All of these Residence time distribution (RTD) of a reactor is independent ofAnswer: Micro mixing The bubble column fermenter is usually limited toAnswer: Aerobic fermentations A culture in a closed vessel to which no additional medium is added and from which no waste products are removed is called a __________ culture.Answer: Batch If the specific growth rate, μ. is constant with time during the exponential growth period, the equation correlating bacterial number density Cₙ), cell number concentration with respect to time can be expressed asAnswer: Cₙ= Cₙ₀ exp[μ (t - t₀)] The diameter of the baffles in a standard stirred tank bioreactor ranges fromAnswer: 1/10ᵗʰ - 1/12ᵗʰ of the tank diameter During the log phase cell numbers increase exponentiallyAnswer: Because cells are autocatalysts Lag phase occurs mainly due toAnswer: Acclimatization with new environment and substrate