A steam steriliser is used to sterilise liquid medium for fermentation. The initial concentration of contaminating organisms is 10⁸ per litre. For design purposes, the final acceptable level of contamination is usually taken to be 10^-3cells; this corresponds to a risk that one batch in a thousand will remain contaminated even after the sterilisation process is complete. For how long should 1 m³ medium be treated if the temperature is 121⁰C ________________.

 To be safe, assume that the contaminants present are spores of Bacillus stearothermophilus, one of the most heat-resistant microorganisms known. For these spores the activation energy for thermal death is 283 kJ gmo1^-1 and the Arrhenius constant is 10^36.2 s^-1

#Question id: 10536

#Section 6: Plant, Animal and Microbial Biotechnology

Hormonal interactions contribute to plant–insect herbivore interactions such as— ethylene, salicylic acid, and jasmonic acid. In particular, ethylene appears to play an important role in this context, what will be the effect of ethylene when is applied alone and when is applied with other amino acids?

a) ethylene applied together with JA it seems to reduces defense responses

b) Ethylene appears to applied alone to plants, ethylene has little effect on defense-related gene activation

c) when ethylene applied together with JA it seems to enhance JA responses or defense responses are significantly increased

d) Ethylene appears to applied alone to plants, ethylene has more effect on defense-related gene activation

Which of the following combination is correct about ethylene effects?

#Question id: 1549

#Section 2: General Biology

the decision to translate  IgM versus IgD  heavy chains is made at the level of?

#Question id: 8912

#Section 6: Plant, Animal and Microbial Biotechnology

#Question id: 18711

#Section 7: Recombinant DNA technology and Other Tools in Biotechnology

#Question id: 14168

#Section 4: Fundamentals of Biological Engineering

Corn-steep liquor contains 2.5 % invert sugars and 50% water; the rest can be considered solids. Beet molasses containing 50% sucrose, 1% invert sugars, 18% water and the remainder solids, is mixed with corn-steep liquor in a mixing tank. Water is added to produce a diluted sugar mixture containing 2% (w/w) invert sugars. 125 kg corn-steep liquor and 45 kg molasses are fed into the tank.

What is the concentration of solids in the final mixture?