Which phase shows a net loss of viable cells due to unfavorable conditions?

Which phase shows a net loss of viable cells due to unfavorable conditions?

• A. Lag phase
• B. Log phase
• C. Death phase
• D. Stationary phase

Answer: (C)

When environmental conditions deteriorate, the population eventually enters a stage where the number of viable cells declines because the death rate surpasses the birth rate. This is the death phase, which follows stationary growth and marks a net loss of viable cells as nutrients are exhausted and waste products accumulate. In contrast, the lag phase involves little or no division as cells acclimate, the log (exponential) phase features rapid growth with plenty of nutrients, and the stationary phase has balanced birth and death rates with little net change in viable cell numbers. So the phase characterized by a net decline in viable cells due to unfavorable conditions is the death phase.

When environmental conditions deteriorate, the population eventually enters a stage where the number of viable cells declines because the death rate surpasses the birth rate. This is the death phase, which follows stationary growth and marks a net loss of viable cells as nutrients are exhausted and waste products accumulate. In contrast, the lag phase involves little or no division as cells acclimate, the log (exponential) phase features rapid growth with plenty of nutrients, and the stationary phase has balanced birth and death rates with little net change in viable cell numbers. So the phase characterized by a net decline in viable cells due to unfavorable conditions is the death phase.