Final answer:
Rod-shaped bacteria that occur in pairs or chains are referred to as bacilli and they can arrange themselves in pairs called diplobacilli, chains called streptobacilli, or in parallel clusters. The arrangement of the bacterial cells helps in their identification and these characteristics are not phylum-dependent.
Step-by-step explanation:
Rod-shaped bacteria that occur in pairs or chains are known as bacilli. In the microbiology field, the term bacillus refers to the rod shape of the cell. Among bacilli, there are specific types of arrangements, including pairs (diplobacilli), chains (streptobacilli), and {parallel clusters (palisades)}. Through binary fission, non-motile bacilli tend to remain connected post-reproduction, thereby forming these distinctive arrangements. The arrangement and shape of bacterial cells play vital roles in identifying bacterial species.
There is a wide variety of bacilli in terms of phyla, indicating that bacterial shapes are not dependent on bacterial phylum. For instance, Bacillus anthracis causes anthrax and is a member of the class Bacilli, which also includes coccus-shaped species like Staphylococcus aureus, known for causing various infections that can be resistant to antibiotics.