Q.Differentiate between probiotics and pathogenic bacteria

Step 1. Both probiotic and pathogenic bacteria are prokaryotic organisms belonging to Domain Bacteria, sharing the same basic cellular plan — no defined nucleus, circular DNA without histones, a peptidoglycan cell wall, and 70S ribosomes.

Step 2. Probiotic bacteria are live bacteria that confer a health benefit on their host. A classic everyday example is curd, one of the best natural sources of probiotics, containing beneficial species such as Lactobacillus sp., which aid digestion and support a healthy gut environment.

Step 3. Pathogenic bacteria, by contrast, are harmful bacteria that cause disease — either by directly invading and damaging host tissue or by releasing toxins that disrupt the host's normal physiology. …

Contrast the two groups by their effect on the host (beneficial vs. disease-causing) rather than by any structural …

• Assuming probiotic and pathogenic bacteria must be structurally different types of organism, rather than realising both are ordinary bacteria and the difference is purely in host effect. …