Practice Questions

TLS Online TPP Program

#Question id: 12182

The cell cycle is controlled by protein kinases that comprise a catalytic subunit and a regulatory subunit. Which of the following statement is correct regarding to these subunits?

#Section 3: Genetics, Cellular and Molecular Biology

The catalytic subunits, the cyclin-dependent kinases (CDKs), have no kinase activity unless they are dissociated with a regulatory cyclin subunit.
Each CDK can associate with a small number of different cyclins, which determine the substrate specificity of the complex—that is, which proteins it phosphorylates.
Cyclin-CDK complexes activate or inhibit hundreds of proteins involved in cell cycle progression by phosphorylating or dephosphorylating them at specific regulatory sites.
Proper progression through the cell cycle is governed by activation of the appropriate homodimeric protein kinase complex at the appropriate time.

More Questions

TLS Online TPP Program

#Question id: 27175

#Section 5: Bioprocess Engineering and Process Biotechnology

A bacterial culture having a specific oxygen uptake rate of 5 mmol O2 (g- DCW)^-1h-1 is being grown aerobically in a fed-batch reactor. The maximum value of the volumetric oxygen transfer coefficient is 0.18 s for the stirred tank bioreactor and the critical dissolved oxygen concentration is 20% of the saturation concentration (8 mg L^-1). The maximum density to which the cells can be grown in the fed-batch process, without the growth being limited by oxygen transfer, is approximately

TLS Online TPP Program

#Question id: 27176

#Section 5: Bioprocess Engineering and Process Biotechnology

A strain of Azotobacter vinelandii is cultured in a 15-m³ stirred fermenter for alginate production. Under current operating conditions, ka is 0.17 s¹. The solubility of oxygen in the broth is approximately 8 × 10^-3 kg m ^-3.

(a) The specific rate of oxygen uptake is 12.5 mmol g^-1h^-1. What is the maximum cell concentration supported by oxygen transfer in the fermenter.............in g/l

TLS Online TPP Program

#Question id: 27177

#Section 5: Bioprocess Engineering and Process Biotechnology

A strain of Azotobacter vinelandii is cultured in a 15-m³ stirred fermenter for alginate produc- tion. Under current operating conditions, k_La is 0.17 s^-1. The solubility of oxygen in the broth is approximately 8 × 10^-3 kg m^-3.

(b) The bacteria suffer growth inhibition after copper sulphate is accidentally added to the fermentation broth just after the start of the culture. This causes a reduction in the oxygen uptake rate to 3 mmol g^-1 h^-1. What maximum cell concentration can now be supported by oxygen transfer in the fermenter?.....g/l

TLS Online TPP Program