GATE XL topic:microbial-growth PYQs & Answers — Page 3

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topic:microbial-growth

Questions 21–25 of 25. Imported answers require independent review unless marked reviewed.

Topic practice 25 questionsPage 3 of 3

A continuous cell culture being carried out in a stirred tank reactor is described in terms of its cell mass concentration X and substrate concentration S. The concentration of the substrate in the sterile feed stream is S_F = 10 g/L and yield coefficient Y_{x/s} = 0.5. The flow rates of the feed stream and the exit stream are equal (F=5 mL/min) and constant. If the specific growth rate (h⁻¹) μ = \frac{0.3\ S}{(1+S)}, the steady state concentration of S is ____ g/L (up to 1 decimal point).

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The initial concentration of cells (N₀) growing unrestricted in a culture is 1.0×10⁶ cells/mL. If the specific growth rate (μ) of the cells is 0.1 h⁻¹, the time required for the cell concentration to become 1.0×10⁸ cells/mL is ________ hours (up to 2 decimal points).

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Microbes that have their optimal growth rate near 15 °C but can still grow at 0 °C to 20 °C are known as

Your answerChoose one option.

mesophiles

psychrotrophs

psychrotolerant

psychrophiles

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A bactericidal agent X is added after 3 hours of growth of a bacterial culture. Following the addition of X, the bacterial growth was measured using the standard plate count method till 24 hours. Which one of the following figures is the most accurate representation of the action of X?

Your answerChoose one option.