Question

The first stage of the S-shaped growth curve of the population is

• A. Log phase
• B. Lag phase
• C. Phase of acceleration
• D. Phase of deceleration

Answer 1

The correct option is B

Lag phase

The correct option is B.

Explanation for correct option:

1. The growth curve is the graphical representation that depicts the growth of cells in an experimental culture over time.
2. They are used to study the rise and fall of populations of an organism.
3. The lag phase is the earliest phase in the growth curve in which the bacteria begins to adapt to the growth conditions.
4. Then, it is followed by the fastest phase called the log phase.
5. Here, maximum growth of the organism is reached.

Explanations for incorrect options:

Option A:

1. The log phase is also referred to as the exponential phase in which the cells double in number via binary fission.
2. The number of cells increases in a logarithmic fashion.

Option C:

The phase of acceleration refers to the logarithmic phase in which the cells multiply fast.

Option D:

The deceleration phase occurs after the growth phase in which the cell growth is decelerated due to the depletion of nutrients or the accumulation of toxic wastes in the growth medium.

Final answer: The first stage of the S-shaped growth curve of the population is the lag phase.