NEET UG · Biology · Breathing and Exchange of Gases

Oxygen Dissociation Curve: NEET previous year questions

6 questions in ten years of NEET, in 4 of 10 papers. Pattern: Due again. Here is how it is asked and which ideas come back.

Asked in 10 years: 6; about 0.6 per paper
Years asked: 4/10; last asked 2024
Chance of a question next paper: 50%; historical rate, how we compute it
Weighted estimate: 0.5; model; history: 0.6 a paper on average, typically 0–1

Key findings

01
Asked in 4 of 10 papers, 6 questions in all: #134 of 204 topics by ten-year total. It comes back every 1.3 years on average. Last asked in 2024.
02
67% of its questions since 2018 tested an idea never asked before; 1 repeated an idea from the year before.
03
The most repeated idea is Alveolar Conditions for Oxyhemoglobin, asked 3 times (2020, 2021, 2024), usually as “identify wrong statement on oxygen transport”.
04
NEET has asked 3 of the 88 ideas in this topic; 82 have never been asked, directly or indirectly.
05
Mostly asked as one-line MCQ (83%); 83% easy, 0% hard, and down from 0.7 to 0.3 questions a paper since 2024.

Questions per year

Up to 2023: 0.7; per paper
Since 2024: 0.3; -0.4
Usual gap: 1.3 yrs; between papers asking it
Swing: ±0.8; questions, year to year

How it is asked

Difficulty, format and skill

Across all 6 questions on Oxygen Dissociation Curve since 2017.

Difficulty

QUESTIONS

Easy5 · 83%
Medium1 · 17%
Hard0 · 0%

Format

One-line MCQ · 5 Q83%
Assertion–reason · 1 Q17%

Skill tested

Concept · 4 Q67%
Recall · 2 Q33%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier paper

Coverage of the topic

NEET has asked 3 of the 88 ideas in this topic. 82 have never been asked yet.

Asked directly3 · 3%
Touched inside another question3 · 3%
Never asked82 · 93%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

ideaAskedShareYears’17’18’19’20’21’22’23’24’25’26

Repeated3 · 50%50%3/10
- 2024 · Q171
  Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?
  easyOne-line MCQ
- 2021 · Q169
  Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.
  easyOne-line MCQAsked the year before
- 2020 · Q19
  Identify the wrong statement with reference to transport of oxygen.
  mediumOne-line MCQNew idea
1 · 17%17%1/10
1 · 17%17%1/10
1 · 17%17%1/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

Every idea inside this topic

4 different ideas were tested; 1 came more than once. Effect of pO2 on Binding is the foundation for 48 other ideas in the syllabus.

Alveolar Conditions for Oxyhemoglobin3×
identify wrong statement on oxygen transport
One-line MCQ · 6% next · foundation for 1
Normal Oxygen Delivery Rate1×
recall of oxygen delivered per 100 ml blood
One-line MCQ · 4% next · foundation for 2
Effect of pO2 on Binding1×
assertion-reason on high altitude hypoxia
Assertion–reason · 4% next · foundation for 48
Partial Pressures of O2 and CO21×
recall partial pressures at site of exchange
One-line MCQ · 4% next

Idea	Times	Format	Chance next	Foundation for
Alveolar Conditions for Oxyhemoglobinidentify wrong statement on oxygen transport	3	One-line MCQConcept	6%	1 ideas
Normal Oxygen Delivery Raterecall of oxygen delivered per 100 ml blood	1	One-line MCQRecall	4%	2 ideas
Effect of pO2 on Bindingassertion-reason on high altitude hypoxia	1	Assertion–reasonConcept	4%	48 ideas
Partial Pressures of O2 and CO2recall partial pressures at site of exchange	1	One-line MCQRecall	4%	–

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Oxygen Dissociation Curve questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20241 question

Q171
Which of the following factors are favourable for the formation of oxyhaemoglobin in alveoli?
Idea: Alveolar Conditions for Oxyhemoglobin
EasyOne-line MCQ

NEET 20221 question

Q166
Under normal physiological conditions in human being, every 100 ml of oxygenated blood can deliver ______ ml of $\mathrm{O_2}$ to the…
Idea: Normal Oxygen Delivery Rate
New ideaEasyOne-line MCQ

NEET 20213 questions

Q163
The partial pressures (in mm Hg) of oxygen ( $\mathrm{O_2}$ ) and carbon dioxide ( $\mathrm{CO_2}$ ) at alveoli (the site of diffusion) are :
Idea: Partial Pressures of O2 and CO2
New ideaEasyOne-line MCQ
Q169
Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.
Idea: Alveolar Conditions for Oxyhemoglobin
Asked last yearEasyOne-line MCQ
Q195
Assertion (A) : A person goes to high altitude and experiences 'altitude sickness' with symptoms like breathing difficulty and heart…
Idea: Effect of pO2 on Binding
New ideaEasyAssertion–reason

NEET 20201 question

Q19
Identify the wrong statement with reference to transport of oxygen.
Idea: Alveolar Conditions for Oxyhemoglobin
New ideaMediumOne-line MCQ

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.