Prokaryotes are classified under two distinct domains–Bacteria and Archaea. The domain Bacteria has the kingdom Eubacteria, which contains prokaryotes that contain peptidoglycan in its cell walls. On the other hand, the domain Archaea contains the kingdom Archaebacteria. Prokaryotes in this kingdom have cells that have no peptidoglycan in its cell walls.

Prokaryotes differ in size, shape, and movement. They also have differences in their cell wall composition, as well in their method of obtaining and releasing energy.

The three ecological roles of prokaryotes are listed below:

1. Decomposers – Bacterial decomposers help purify water, and break down waste and organic matter.

2. Producers – Photosynthetic prokaryotes are consumed by aquatic organisms.

3. Nitrogen fixers – Nitrogen-fixing prokaryotes provide nitrogen that can be utilized by plants and other organisms.

Bacteria can cause disease in two ways:
1. By attacking and destroying living cells
2. By releasing chemicals or toxins that disrupt the homeostasis

Since people have no immunity to the viruses that cause emerging diseases, they can spread rapidly. For this reason, emerging diseases can be very alarming.

The answer is no. Unlike medicines that cure diseases, vaccinations are used as a preventive measure. It introduces a weakened strain of bacteria into our body in order to help the immune system to develop immunity against the bacteria. In this case, it is better to consult a doctor and drink the prescribed antibiotics that will fight off the bacterial infection.