Broth cultures are liquid media used in microbiology to grow and maintain microorganisms, such as bacteria and yeast. These cultures provide essential nutrients, allowing the organisms to thrive and reproduce. They are often used in laboratories for research, diagnostics, and testing purposes. In a broth culture, microorganisms are suspended in a nutrient-rich solution, which can include ingredients like peptone, yeast extract, and salts. This method is beneficial for studying the growth patterns and characteristics of specific organisms, as well as for producing large quantities of cells for further analysis or experimentation.