275
MCQ Questions
40
Assertion-Reason
82
NEET 2025 Pattern
21
Previous Year Q
NCERT Mapping
Respiration in plants is from NCERT Class 11 Biology, Chapter 12, under the unit Plant Physiology. This chapter carries approximately 3% weightage in NEET, based on analysis of the last 10 years of question papers. MedicNEET covers this chapter with 397 questions — every question built from line-by-line NCERT analysis.
Topics in Respiration in plants
Respiratory Quotient
Glycolysis
– "Do Plants Breathe?"
The respiratory balance sheet
Fermentation
Amphibolic Pathway
Aerobic respiration
Sample Questions — Respiration in plants
Try 5 free questions below. Get all 397 in the MedicNEET app.
MCQ
Why is aerobic respiration called amphibolic rather than purely catabolic?
✅ Correct Answer: B
The same pathway is used for both energy release (catabolism) and biosynthesis (anabolism).
MCQ
Match each pathway with its role/ATP yield:
COLUMN I
A. Glycolysis
B. Fermentation
C. TCA cycle
D. ETS
COLUMN II
1. Cytoplasm; universal, yields 2 ATP
2. Regenerates NAD⁺ without O₂
3. Produces NADH, FADH₂, CO₂
4. Inner membrane; electrons passed to O₂ and coupled to ATP synthase
✅ Correct Answer: A
Glycolysis in cytoplasm yields 2 ATP (12.2); fermentation maintains NAD⁺ (12.2); TCA produces reduced coenzymes and CO₂ (12.3); ETS transfers electrons to O₂ with ATP coupling (12.4).
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MCQ
A mitochondrion is supplied with malate (organic acid). Predict events:
1. Malate enters TCA cycle as intermediate.
2. RQ exceeds 1.
3. ETS generates ATP.
✅ Correct Answer: D
Organic acids enter TCA (12.3), give RQ > 1 (12.7), and via ETS generate ATP (12.4).
Assertion-Reason
Assertion (A): The electron transport system is a metabolic pathway in cellular respiration.
Reason (R): The electron transport system is present in the mitochondrial matrix.
✅ Correct Answer: A
NCERT confirms ETS is a metabolic pathway in respiration (Assertion true). However, NCERT states “The metabolic pathway through which the electron passes from one carrier to another, is called the electron transport system (ETS) and it is present in the inner mitochondrial membrane.” The Reason falsely places ETS in matrix instead of inner membrane (false).
NEET 2025 Pattern
Which of the following statements regarding Respiratory Quotient (RQ) and its variations are correct?
S1: The RQ value is calculated as the ratio of the volume of CO₂ evolved to the volume of O₂ consumed during respiration.
S2: In certain succulent plants, like CAM plants, RQ values can fluctuate significantly throughout a 24-hour cycle due to the alternate synthesis and breakdown of organic acids.
S3: During anaerobic respiration, the RQ is considered infinite because no carbon dioxide is released in the absence of oxygen.
S4: The RQ for carbohydrates like glucose is consistently 1.0 because they possess a balanced proportion of carbon, hydrogen, and oxygen atoms.
S5: When proteins are used as respiratory substrates, their RQ value typically falls below 0.7 due to their complex structure and low oxygen content.
✅ Correct Answer: A
Let's evaluate each statement:
S1: This statement is correct. The NCERT defines RQ as the ratio of the volume of CO₂ evolved to the volume of O₂ consumed during respiration.
S2: This statement is correct. In CAM plants, organic acids are synthesized at night and broken down during the day, leading to fluctuations in the respiratory substrate and thus the RQ value.
S3: This statement is incorrect. While RQ is infinite during anaerobic respiration (because O₂ consumption is zero), CO₂ can still be released, for example, in alcoholic fermentation where pyruvic acid is converted to CO₂ and ethanol.
S4: This statement is correct. NCERT states that for carbohydrates, such as glucose, when completely oxidized, the RQ is 1.0 due to equal amounts of CO₂ evolved and O₂ consumed.
S5: This statement is incorrect. The RQ for proteins is approximately 0.9, which is not typically below 0.7 (the RQ for fats like tripalmitin is 0.7).
Based on the evaluation, statements S1, S2, and S4 are correct.
Therefore, option A is the correct answer.
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Frequently Asked Questions
How many Respiration in plants questions does MedicNEET have?
MedicNEET has 397 questions for Respiration in plants, including 275 MCQs, 40 Assertion-Reason questions, and 82 NEET 2025-style long-form questions.
What is the NEET weightage of Respiration in plants?
Respiration in plants carries approximately 3% weightage in NEET, based on analysis of the last 10 years of papers. It falls under the Plant Physiology unit of Class 11 Biology.
Are Respiration in plants questions NCERT-based?
Yes, all MedicNEET Respiration in plants questions are built from line-by-line analysis of NCERT Class 11 textbook. Every question maps to specific NCERT pages and concepts.