Final answer:
The student's question refers to the spread plate method, a microbiological technique used to estimate cell count in a sample by spreading a diluted inoculum across a solid medium and allowing individual colonies to form.
Step-by-step explanation:
Spread Plate Method for Bacterial Dilution:
The subject in question is referring to the spread plate method, a microbiological technique used in Biology for estimating the number of viable cells in a sample. This method involves spreading an inoculum across the surface of a solid medium, allowing for cell separation and colony formation. A serial dilution is typically used to reduce the concentration of cells, ensuring that colonies are sufficiently spaced to be counted individually.
The spread plate method is preferred when colonies will be counted and requires even spreading of the liquid sample across an agar plate. By counting the resulting colonies, which each originate from a single cell, microbiologists can estimate the number of cells in the original sample. This approach is essential for creating pure cultures and is fundamental to microbiological studies such as the investigation of environmental samples or the analysis of microbial growth.