NEET BIOLOGY

Detailed explanation-1: -Bacteria have characteristic shapes (cocci, rods, spirals, etc.) and often occur in characteristic aggregates (pairs, chains, tetrads, clusters, etc.). These traits are usually typical for a genus and are diagnostically useful.

Detailed explanation-2: -Bacteria are classified into five groups according to their basic shapes: spherical (cocci), rod (bacilli), spiral (spirilla), comma (vibrios) or corkscrew (spirochaetes).

Detailed explanation-3: -Bacteria are prokaryotes, lacking well-defined nuclei and membrane-bound organelles, and with chromosomes composed of a single closed DNA circle. They come in many shapes and sizes, from minute spheres, cylinders and spiral threads, to flagellated rods, and filamentous chains.

Detailed explanation-4: -Bacterial cells do not have an organized nucleus.