Two General Science staples — nanotechnology's growing real-world applications, and the basic biology of how diseases and immunity work.
Nanotechnology involves manipulating matter at the nanoscale (roughly 1-100 nanometres), where materials often display different physical/chemical properties than in bulk form. Applications span medicine (targeted drug delivery, diagnostics), electronics (smaller, faster chips), energy (better batteries and solar cells), and water purification. India's Nano Mission supports research in this field, alongside ongoing debate over ethical, social and regulatory questions — toxicity, environmental impact, and equitable access.
An antigen is any substance (often on a pathogen's surface) that triggers an immune response; the body responds by producing antibodies — proteins that specifically recognise and neutralise that antigen. Vaccines work by exposing the immune system to a weakened, inactivated, or partial version of a pathogen (or, in newer mRNA vaccines, genetic instructions to build a piece of it), training the immune system to respond quickly if it encounters the real pathogen later.
Essential vitamins (A, B-complex, C, D, E, K) each prevent specific deficiency diseases — e.g., Vitamin A deficiency causes night blindness, Vitamin D deficiency causes rickets. Communicable diseases spread from person to person (via pathogens like bacteria, viruses, parasites) and are distinguished from non-communicable diseases (like diabetes, most cancers) which don't spread between individuals — a key public health policy distinction.
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