Final answer:
When bacteria form grapelike clusters, the prefix used is “staphylo-”, as seen in the genus Staphylococcus, such as Staphylococcus aureus.
Step-by-step explanation:
When bacteria are found in grapelike clusters, the prefix that is used is staphylo-. This term is derived from the Greek word 'staphyle,' meaning a bunch of grapes, and it is typically associated with the genus Staphylococcus. For example, Staphylococcus aureus is a type of bacteria that can form these characteristic clusters.
An important concept in microbiology is the ability to describe the morphology (shape) and arrangement of bacterial cells which helps in identification and understanding the biology of the microorganisms. In addition to staphylococci, other arrangements include chains of cocci called streptococci, pairs known as diplococci, and bacilli that can be arranged in pairs (diplobacilli), chains (streptobacilli), or in palisade formations.