Bacteria are prokaryotic microorganisms that can have unique structures like capsules, pili, and flagella. They come in different shapes like coccus, bacillus, and spirillum. Some bacteria form endospores to survive extreme environmental conditions. Bacteria play important environmental and industrial roles like sewage disposal and genetic engineering. While some cause disease, others in the human body aid digestion and produce vitamins. Viruses consist of genetic material and proteins but are not living without a host cell. They invade hosts and hijack cellular mechanisms to replicate. Both bacteria and viruses can transmit diseases via various routes. Antibiotics treat bacterial but not viral infections.

3. Where are they found? Every where!

23. Remember to organize your notes and study for your test!