Q."Bacteria are friends and foes of man." Discuss.

[!TLDR]

The question asks for a discussion of bacteria as both beneficial and harmful to humans. …

Bacteria influence human life in ways that are overwhelmingly beneficial as well as, in a smaller number of cases, harmful, which is why they are often described as both friends and foes of man. As friends, bacteria perform several essential roles. In biotechnology and genetic engineering, bacteria such as Escherichia coli - the intestinal bacterium widely used as a host organism - are used to manufacture useful products: a desired gene is inserted into a bacterial plasmid, and the bacterium is grown in bulk to produce the corresponding protein. In the natural environment, decomposer bacteria break down dead organic matter, releasing and recycling nutrients back into the soil and atmosphere so that other organisms can use them again. Nitrogen-fixing bacteria such as Rhizobium, living in the root nodules of leguminous plants, convert atmospheric nitrogen into forms plants can absorb, directly supporting soil fertility and agricultural productivity. Bacteria living naturally within the human gut also assist with digestion and other bodily processes. …

• Discussing only the harmful (disease-causing) side of bacteria and giving it undue weight relative to their beneficial roles. …