UPSC Zoology optional solved pyqs

🏆 Nobel Prize in Physiology or Medicine 2026 Awarded to: Karl Deisseroth, Peter Hegemann & Georg Nagel For: Discoveries leading to optogenetics, enabling scientists to switch individual nerve cells on or off using light. 🔬 Core concept • Hegemann & Nagel studied the green alga Chlamydomonas and identified channelrhodopsin, a light-gated ion channel. • Deisseroth helped develop its use in neurons → light can precisely activate or inhibit specific neurons. • Thus: Gene → light-sensitive protein → light → ion flow → change in membrane potential → neuronal activity. 🎯 Zoology Optional relevance Use as a value addition in: 1. Cell Biology – ion channels, membrane potential, membrane transport. 2. Animal Physiology – nerve impulse and neuronal signalling. 3. Ethology – neural basis of behaviour, memory and emotions. 4. Genetics/Biotechnology – genetic introduction of opsins into specific cells. 5. Evolution/Comparative Biology – a protein discovered in an alga becoming a tool for studying the mammalian brain. One-line value addition “The 2026 Nobel-winning optogenetics demonstrates how genetically encoded light-sensitive ion channels can provide precise control over neuronal activity, linking molecular mechanisms of membrane physiology with behaviour.” Keywords to remember: Chlamydomonas → Channelrhodopsin → Light-gated ion channel → Neuron → Optogenetics