Practice Questions

TLS Online TPP Program

#Question id: 341

Which force can stabilize a DNA double-helix?

#Section 2: General Biology

Hydrophobic bases are found in the interior of the helix where each base-pair is stabilized by the same number of hydrogen bonds.
Hydrophilic sugar-phosphate groups are found on the exterior of the helix where they can interact with water.
Non-covalent N-glycosidic bonds can form between nitrogenous bases in opposite strands in the helix.
Covalent base-stacking interactions can occur between adjacent bases within the same strand in the helix.

More Questions

TLS Online TPP Program

#Question id: 14259

#Section 5: Bioprocess Engineering and Process Biotechnology

C. roseus cells immobilized in Ca-alginate beads of diameter 0.5 mm are used for production of indole alkaloids (IA) in a fluidized-bed bioreactor. The rate limiting nutrient is glucose and no intraparticle diffusion limitations exist. Use the following data: Flow rate of the feed: Q = 1 l/h, Glucose in the feed: So = 30 g/l, Plant Cell Concentration: X = 6 g/l reac. The rate constant for IA formation: k = 5 d-1 (g/l)^-1 Ks = 0.4 g/l, Column diameter: Do = 0.15 m. Growth is negligible and Monod kinetics is valid. For 95% glucose conversion determine volume.

TLS Online TPP Program

#Question id: 14260

#Section 5: Bioprocess Engineering and Process Biotechnology

C. roseus cells immobilized in Ca-alginate beads of diameter 0.5 mm are used for production of indole alkaloids (IA) in a fluidized-bed bioreactor. The rate limiting nutrient is glucose and no intraparticle diffusion limitations exist. Use the following data: Flow rate of the feed: Q = 1 l/h, Glucose in the feed: So = 30 g/l, Plant Cell Concentration: X = 6 g/l reac. The rate constant for IA formation: k = 5 d-1 (g/l)^-1 Ks = 0.4 g/l, Column diameter: Do = 0.15 m. Growth is negligible and Monod kinetics is valid. For 95% glucose conversion determine height of the column

TLS Online TPP Program

#Question id: 14261

#Section 5: Bioprocess Engineering and Process Biotechnology

C. roseus cells immobilized in Ca-alginate beads of diameter 0.5 mm are used for production of indole alkaloids (IA) in a fluidized-bed bioreactor. The rate limiting nutrient is glucose and no intraparticle diffusion limitations exist. Use the following data: Flow rate of the feed: Q = 1 l/h, Glucose in the feed: So = 30 g/l, Plant Cell Concentration: X = 6 g/l reac. The rate constant for IA formation: k = 5 d-1 (g/l)^-1 Ks = 0.4 g/l, Column diameter: Do = 0.15 m. Growth is negligible and Monod kinetics is valid. If Yp/s is 0.02 g IA/g glu, determine IA concentration in the effluent.

_______________

TLS Online TPP Program

#Question id: 14262

#Section 5: Bioprocess Engineering and Process Biotechnology

The BOD5 value of a waste-water feed stream to an activated-sludge unit is S0 = 300 mg/l, and the effluent is desired to be S = 30 mg/l. The feed flow rate is F = 2× 10^7 l/day. For the recycle ratio of α = 0.5 and a steady-state biomass concentration of X = 5 g/l, Use the following kinetic parameters:

calculate Required reactor volume (V).

_______________10^6

TLS Online TPP Program

#Question id: 14263

#Section 5: Bioprocess Engineering and Process Biotechnology

The BOD5 value of a waste-water feed stream to an activated-sludge unit is S0 = 300 mg/l, and the effluent is desired to be S = 30 mg/l. The feed flow rate is F = 2× 10^7 l/day. For the recycle ratio of α = 0.5 and a steady-state biomass concentration of X = 5 g/l, Use the following kinetic parameters:

calculate Biomass concentration in recycle (Xr).

TLS Online TPP Program

#Question id: 14264

#Section 5: Bioprocess Engineering and Process Biotechnology

The BOD5 value of a waste-water feed stream to an activated-sludge unit is S0 = 300 mg/l, and the effluent is desired to be S = 30 mg/l. The feed flow rate is F = 2× 10^7 l/day. For the recycle ratio of α = 0.5 and a steady-state biomass concentration of X = 5 g/l, Use the following kinetic parameters:

calculate Hydraulic residence time