Final answer:
To identify a conditional mutant between a quick and a slow stop, one should subject the strain to different temperatures and observe growth patterns, as conditional mutants typically display growth differences under non-permissive conditions. Other methods like observing growth rates or complementation may not specifically highlight the conditional aspect of the mutation.
Step-by-step explanation:
To identify whether a quick or slow stop has two cultures - one wild-type (wt) and the other a conditional mutant - one can employ a strategy that involves monitoring and comparing the growth characteristics of each culture under different conditions. From the provided options, the most effective method would be to subject the mutant strain to different temperatures and observe its growth characteristics (Option C). This is because conditional mutants often exhibit altered growth patterns when exposed to non-permissive conditions such as increased or decreased temperatures.
For example, a temperature-sensitive mutant might grow normally at a permissive temperature (such as 23 °C) but demonstrate impaired growth or no growth at a non-permissive temperature (such as 37 °C). Contrastingly, observing growth rates over time or complementing mutants with wild-type extracts can provide information about general growth and metabolic differences but may not specifically identify the conditional nature of a mutation. Experimentation using these approaches, including replica plating and assessing growth on nutritionally complete versus deficient media, can reveal differences in metabolic requirements, such as those exhibited by auxotrophic mutants.
It is also beneficial to plate cells on nutritionally complete media to ensure they are being properly transferred when using replica plating. This allows the identification of mutants, such as histidine auxotrophs, which can grow on complete media but not on media lacking specific nutrients like histidine.