A$-$ false

$1\mathrm{.}2\mathrm{.}1.$ Which of the following statements are correct for the production of human insulin in E$.$ colit? Insulin is a complex protein undergoing glycosylation.

E$.$ coll is chosen as host organism for the similarity of its post$-$translational modifications to human cells.

High growth rate of $E.$ coli makes its use for industrial scale production more advantageous.

With the ability to grow in suspension culture, E$.$ coli is easy to cultivate in bioreactor operations.

Mammalian cells would be a better choice for human insulin production, as the risk for contamination is less for mammalian cells.

$1\mathrm{.}2\mathrm{.}2.$ Which of the following are true for fed$-$batch operations?

All nutrients are added in increments at different times throughout the course of fermentation.

Only the substrate, usually either carbon$-$ or nitrogen$-$source, is added in increments at different times throughout the course of fermentation.

In fed$-$batch bioreactor systems, volume is kept constant throughout the operation.

In fed$-$batch bioreactor systems, linear increase of cell concentration could be achieved.

Fed$-$batch operations are not suitable to use when the nutrient$/$substrate is inhibitory to the cells or affect the mass transfer rate.

$3.$ Which of the following$($s$)$ is$/$are true for critical dilution rate $(D_{\text{c}\text{r}\text{i}\text{t}})?$

At critical dilution rate the steady$-$state substrate concentration becomes zero.

At critical dilution rate the steady$-$state biomass concentration becomes zero.

To avoid washout of cells from the chemostat, the operating dilution rate must always be less than critical dilution rate.

To maximize product formation in a chemostat, the operating dilution rate must always be kept higher than the critical dilution rate.

If no substrate consumption occurs in a chemostat, we may suspect that cell washout has xcurred in the system.