Biotechnology & genetics

Answer: (a) 1 only

Hydrogels are water-swollen networks of cross-linked polymers, soft and compatible with body tissue. Their best-established use is medical: a drug trapped in the gel is released over time at a controlled rate, and the gels are also used in wound dressings, contact lenses and tissue engineering. UPSC's key treats statements 2 and 3 as incorrect.

• ✓ 1. Hydrogels can hold small drugs, proteins or even cells and release them over time and at a chosen site, and several such delivery systems are in clinical use.
• ✗ 2. UPSC's official key treats this statement as incorrect; we could not confirm the detail from an official source, so we do not explain it here.
• ✗ 3. UPSC's official key treats this statement as incorrect; we could not confirm the detail from an official source, so we do not explain it here.

Remember · Hydrogel = cross-linked, water-absorbing polymer network; soft, biocompatible. Uses: controlled drug release, wound dressings, soft contact lenses, tissue engineering.

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 1 Oct 2026 (how we verify). Permalink · Report an error

Answer: (d) Wastewater treatment technologies

A membrane bioreactor (MBR) is a sewage and industrial-effluent treatment system. It joins the usual biological step, in which microbes break down organic waste, with fine membrane filtration that holds back solids and bacteria, so it produces clean, reusable water from a much smaller plant than conventional settling tanks.

• ✓ (d) The US EPA describes MBRs as a secondary-treatment technology for municipal wastewater that combines a suspended-growth biological reactor with microfiltration, removing nitrogen, phosphorus, bacteria and organic load.
• ✗ (c) Vaccine and biologics production uses bioreactors (fermenters) too, but the term 'membrane bioreactor' refers to the filtration-based wastewater process.
• ✗ (b) Nano drug-delivery systems use carriers such as liposomes and nanoparticles; they are not membrane bioreactors.

Remember · Membrane bioreactor = activated-sludge (microbial) treatment + membrane micro/ultrafiltration; compact, high-quality effluent fit for reuse. Used for sewage and industrial wastewater.

📘 Read it in NCERT: Class 12 Biology, Ch 8 (practise this chapter)

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error

Answer: (d) Statement-I is incorrect, but Statement-II is correct

India does import apples from the United States, so Statement-I is wrong. Statement-II is right: the Food Safety and Standards Act, 2006 bars the import of genetically modified articles of food except as the Act and its regulations permit.

• ✗ Statement-I The Ministry of Commerce and Industry records apple imports from the USA of US$ 5.27 million in FY 2022-23, down from US$ 145 million in FY 2018-19 after India imposed an additional 20% duty on US apples in 2019. Imports fell but never stopped, and in June 2023 India announced it would remove that extra duty.
• ✓ Statement-II Section 22 of the Food Safety and Standards Act, 2006 says that, save as otherwise provided under the Act and its regulations, no person shall manufacture, distribute, sell or import genetically modified articles of food. Such food can therefore enter only where the law permits it.

Remember · India does import US apples (US$ 5.27 million in FY 2022-23). Section 22 of the FSS Act 2006 bars import of GM food articles unless the Act and regulations permit.

Question and answer: UPSC's official GS Paper I (2024, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). Permalink · Report an error