UPSC Prelims 2021 Q73: Science & Technology – Health & Diseases
- (a) genes introduced in the genetically modified plants
- (b) development of India's own satellite navigation system
- (c) radio collars for wildlife tracking
- (d) spread of viral diseases
Answer: (d) spread of viral diseases
Explanation
ACE2: Angiotensin-Converting Enzyme 2
ACE2 (Angiotensin-Converting Enzyme 2) is a cell surface receptor protein in humans, primarily expressed in lung, heart, kidney and intestinal cells. It became globally famous in 2020 because SARS-CoV-2 (the COVID-19 virus) uses ACE2 as its entry receptor to infect human cells.
| Application | ACE2 Relevance | Detail |
|---|---|---|
| Spread of viral diseases | YES - PRIMARY CONTEXT | SARS-CoV-2 spike protein binds ACE2 receptor to enter cells. Same for original SARS-CoV (2003). ACE2 expression pattern explains why lungs are affected. |
| GM plants | NO | ACE2 is a human protein, not used in GM crops. |
| Satellite navigation | NO | Unrelated - India's system is NavIC (IRNSS). |
| Radio collars for wildlife | NO | Unrelated. |
Answer: (d) spread of viral diseases.
Why each option is right or wrong
- (a) Incorrect. ACE2 is a human cell receptor, not a gene inserted in GM plants.
- (b) Incorrect. India's satellite navigation system is NavIC (IRNSS), not related to ACE2.
- (c) Incorrect. Wildlife radio collars use VHF/UHF or GPS/GSM technology - unrelated to ACE2.
- (d) CORRECT. ACE2 (Angiotensin-Converting Enzyme 2) is the cell surface receptor that SARS-CoV-2 uses to enter human cells. Also used by the original SARS-CoV (2003). ACE2 explains COVID-19's tropism for lungs, heart, kidney and gut.
Key point
ACE2 = Angiotensin-Converting Enzyme 2 = human cell receptor SARS-CoV-2 uses to enter cells. Also the entry receptor for SARS-CoV (2003). Explains COVID's lung/heart/kidney tropism. Related to spread of viral diseases (COVID-19).
Remember
The term 'ACE2' (Angiotensin-Converting Enzyme 2) is talked about in the context of the SPREAD OF VIRAL DISEASES - specifically as the cell surface receptor used by SARS-CoV-2 (COVID-19 virus) and SARS-CoV to enter human cells. Correct answer: (d).
Common mistakes
- Confusing ACE2 (receptor) with ACE inhibitors (BP-lowering drugs like Enalapril, Ramipril).
- Not knowing SARS-CoV-2 uses ACE2 + TMPRSS2 (transmembrane protease) for cell entry.
- Missing that ACE2 is part of the renin-angiotensin-aldosterone system (RAAS) - regulates blood pressure.
Exam tip
ACE2 = SARS-CoV-2 entry receptor. Spike protein RBD binds ACE2; TMPRSS2 primes the spike. Neutralising antibodies (from vaccines/prior infection) block this binding. Zoonotic spillover: bat/pangolin coronaviruses evolved ACE2 affinity in humans.
Sources
- ICMR-NIV - SARS-CoV-2 Cell Entry Mechanisms
- The Lancet / Nature Reviews - ACE2 and COVID-19 (2020)