Question

For bacterial growth in a cell culture, growth law is very similar to the law of radioactive decay. Which of the following graphs is most suitable to represent bacterial colony growth? Where \( N \) - Number of Bacteria at any time, \( N_0 \) - Initial number of Bacteria.

• A.

  

• B.

  

• C.

  

• D.

  

Hint:

For bacterial growth, use exponential growth models, which show a rapid increase initially followed by leveling off as resources become limiting.

Answer 1

The Correct Option is A

To understand which graph is most suitable for representing bacterial colony growth, we need to consider the law that governs bacterial growth:

Simplifying, the number of bacteria \( N \) at any time \( t \) can be expressed as \( N(t) = N_0 \times e^{kt} \), where \( N_0 \) is the initial number of bacteria and \( k \) is the growth rate constant. This equation resembles the exponential growth equation similar to the law of radioactive decay.

An exponential growth model like this is best represented using a graph where:

• The y-axis (vertical axis) displays the number of bacteria, \( N(t) \).
• The x-axis (horizontal axis) represents time, \( t \).
• The curve shows exponential increase as time progresses.

The description of the correct graph among the options provided is:

This graph shows an exponential curve, which is the typical indication of bacterial growth over time under the assumption that resources are unlimited.

Thus, this graph best represents bacterial colony growth following exponential growth dynamics similar to radioactive decay. As time increases, the number of bacteria increases exponentially.