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TLS Online TPP Program

#Question id: 11406

Which of the following is true for a critically endangered species?

#XL - R Botany
  1. Reduction in population size is greater than 90%; estimated extinction risk at least 80% in 10 years; area of occupancy less than 10 km^2 generations
  2. Reduction in population size is greater than 90%; estimated extinction risk at least 50% in 10 years; area of occupancy less than 100 km^2 generations
  3. Reduction in population size is greater than 90%; estimated extinction risk at least 50% in 10 years; extent of occurrence less than 10 km^2 generations
  4. Reduction in population size is greater than 90%; estimated extinction risk at least 50% in 10 years; area of occupancy less than 10 km^2 g 
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TLS Online TPP Program

#Question id: 35939

#XL - U Food Technology

A bacterial culture has an initial population of 1×104cells/mL. The population doubles every 30 minutes. What will be the population (in cells/mL) after 2 hours?
TLS Online TPP Program

#Question id: 35940

#XL - U Food Technology

In a batch culture, the specific growth rate (𝜇) of a microbe is 0.693 h-1. What is the doubling time (in hours) of this organism?
TLS Online TPP Program

#Question id: 35941

#XL - U Food Technology

A microbial population declines from 1×108CFU/mL to 1×104CFU/mL in 30 minutes during thermal processing. Assuming first-order death kinetics, calculate the decimal reduction time (D-value) in minutes.
(Use: 𝑁=𝑁0×10−𝑡 / 𝐷)
TLS Online TPP Program

#Question id: 35942

#XL - U Food Technology

A microorganism has a D-value of 5 minutes at 121°C. How much time (in minutes) is required to achieve a 6-log reduction at this temperature?
( Time = D × log reduction)
TLS Online TPP Program

#Question id: 35943

#XL - U Food Technology

If the log of microbial count decreases from 6 to 2 in 20 minutes, what is the D-value (in minutes)?
( D = time / log reduction)
TLS Online TPP Program

#Question id: 35944

#XL - U Food Technology

A microbial culture has a lag phase of 2 hours, an exponential phase lasting 4 hours, and a specific growth rate of 0.35 h-1. What is the final cell concentration if the initial cell count at the beginning of exponential phase is 1×105cells/mL? (𝑁=𝑁0 ⋅ 𝑒𝜇𝑡)