Final answer:
Cell shape, colony shape, and the amount of peptidoglycan in the cell wall are all characteristics used to identify bacteria, but the type of endoplasmic reticulum is not relevant since bacteria lack membrane-bound organelles.
Step-by-step explanation:
Characteristics that allow the identification of bacteria include cell shape, colony shape, and the amount of peptidoglycan in the cell wall. Bacteria can be differentiated based on their morphology, which refers to their form and structure, and through their reaction to certain types of stains, such as the Gram stain. Bacteria can be classified by their cell shape, which includes bacilli (rods), cocci (spheres), and spirilli (spirals). The colony shape is another characteristic, reflecting the macroscopic appearance of bacterial growth on an agar plate, which can be distinctive for different bacterial species and aids in their identification.
The amount of peptidoglycan in the cell wall is another critical feature, which not only characterizes bacteria but also is essential for the Gram stain differentiation into Gram-positive or Gram-negative bacteria, based on the thickness of the peptidoglycan layer. It is important to note that bacteria do not have membrane-bound organelles, such as the type of endoplasmic reticulum found in eukaryotic cells, making this option not relevant for bacterial identification.