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TLS Online TPP Program

#Question id: 378

Which of the following statements about buffers is true?

#Section 4: Fundamentals of Biological Engineering

  1. A buffer composed of a weak acid of pKa = 5 is stronger at pH 4 than at pH 6.

  2. At pH values higher than the pKa, the salt concentration is higher than that of the acid.

  3. The strongest buffers are those composed of strong acids and strong bases.

  4. When pH = pKa, the weak acid and salt concentrations in a buffer are equal.

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TLS Online TPP Program

#Question id: 2923

#Section 3: Genetics, Cellular and Molecular Biology

Injection of an immature Xenopus oocyte with MPF induces:
TLS Online TPP Program

#Question id: 628

#Section 2: General Biology

At fixed substrate concentration, which of the following equation is correct for Dixon plot
TLS Online TPP Program

#Question id: 14850

#Section 1: Engineering Mathematics

A bag contains 2 white and 3 black balls. A ball is drawn 5 times, each being replaced before another is drawn. Find the probability that exactly 4 of the balls drawn are white.
TLS Online TPP Program

#Question id: 1696

#Section 2: General Biology

TCR recognition of peptide-MHC class II depends on:
TLS Online TPP Program

#Question id: 14247

#Section 5: Bioprocess Engineering and Process Biotechnology

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 1036.2 s-1