Recurring NEET Question Patterns (2018–2025)

Top 5 Most Tested Concepts (appear almost every year):

1. CO2 transport percentages — "Which is the most abundant form?" → HCO3– (70%). Distractors: carbaminoHb (23%), dissolved (7%). Appeared in NEET 2019 and 2022.

2. Residual Volume definition — "Air remaining after maximum forced expiration, cannot be expelled." Trap: confuse with FRC (= air after normal expiration). Appeared in NEET 2020 and 2023.

3. Inspiration muscles — "Diaphragm + external intercostals." Trap: internal intercostals (= forced expiration). Quiet expiration = passive. Appeared in NEET 2018 and 2021.

4. Bohr effect factors — Which factors shift curve right? CO2↑, pH↓ (H+↑), temperature↑, 2,3-BPG↑. Decreased temperature = left shift (common distractor). Appeared in NEET 2019, 2023, 2024.

5. Vital Capacity formula — VC = TV + IRV + ERV (not TLC = VC + RV). Appeared multiple years.

Moderate Frequency (every 2–3 years):

• Diffusion membrane layers (3 layers, names in order)
• Chloride shift direction (HCO3– out, Cl– in)
• Lung lobe count (Right = 3, Left = 2)
• O2 transport percentage (97% oxyHb)
• Pneumotaxic centre location and function (pons, limits inspiration)

High-Difficulty Patterns (advanced NEET 2024–2025 style):

• Assertion-Reason on passive expiration
• Application of Bohr effect to clinical scenarios (fever, exercise, altitude)
• Calculation of lung capacities from given volume data
• Identifying spirometry patterns in obstructive vs restrictive disease

Exam Strategy:

• Always check whether a question asks for RV or FRC (they are different)
• When CO2 transport is asked, choose HCO3– unless specifically asking about haemoglobin-bound CO2
• For muscle questions: decide first if it is inspiration or expiration, then internal vs external
• For curve shift questions: right = lower affinity = more O2 released; left = higher affinity = O2 retained