TLS Online TPP Program

#Question id: 11502


Which of these statements is false and therefore does not support the hypothesis that certain eukaryotic organelles originated as bacterial endosymbionts? Such organelles

#XL - S Microbiology
  1. are roughly the same size as bacteria.
  2. can be cultured on agar, because they make all their own proteins.
  3. contain circular DNA molecules.
  4. have ribosomes that are similar to those of bacteria.
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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=𝑁⋅ 𝑒𝜇𝑡)