NEET · Biology · Class 11Respiration in Plants — NEET Biology MCQs
30 questions written by hand against the NCERT chapter. Every wrong option is explained, not just the right one.
30questions
10/14/6easy / medium / hard
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Sample questions from this chapter
A waterlogged root receives little oxygen even though its leaves remain exposed to air. Why is the root especially vulnerable?
- Water converts mitochondrial oxygen into carbon dioxide
- Leaves send oxygen only during darkness
- Roots lack enzymes for glycolysis
- Root cells need oxygen for mitochondrial ATP production, while diffusion through waterlogged soil is slow ✓
Answer: D. Plants have no specialised respiratory organs, so each part relies substantially on local gas diffusion. Flooded soil replaces air spaces with water and sharply slows oxygen supply to respiring roots.
Why not A: Waterlogging restricts gas diffusion rather than chemically converting oxygen into carbon dioxide.
Why not B: Leaf oxygen evolution depends on light, but roots normally obtain much of their oxygen locally from soil air spaces.
Why not C: Root cells perform glycolysis; the limitation arises downstream when aerobic electron disposal fails.
A cytosolic enzyme block prevents glucose from being phosphorylated. Which immediate consequence follows?
- Acetyl-CoA enters the TCA cycle faster
- NADH is oxidised by complex I
- Glucose cannot be trapped and committed to glycolysis as glucose-6-phosphate ✓
- Pyruvate is reduced to lactate
Answer: C. Hexokinase phosphorylation traps glucose in the cell and begins glycolytic investment. A block at the first step deprives both aerobic respiration and fermentation of pyruvate substrate.
Why not A: Acetyl-CoA production requires glycolytic carbon to reach pyruvate first.
Why not B: Complex I acts on mitochondrial NADH and is downstream of cytosolic glucose phosphorylation.
Why not D: Lactate formation consumes pyruvate, which cannot be supplied normally through the blocked pathway.
A glycolytic cell has abundant glucose but its NAD⁺ pool is fully reduced to NADH. Which step stops first?
- Phosphorylation of glucose by ATP
- Cleavage of fructose bisphosphate
- Conversion of PEP to pyruvate
- Oxidation of glyceraldehyde-3-phosphate ✓
Answer: D. Glyceraldehyde-3-phosphate dehydrogenase requires oxidised NAD⁺. This is why fermentation must regenerate NAD⁺ even though it adds no ATP beyond glycolysis.
Why not A: Hexokinase requires ATP and glucose rather than NAD⁺.
Why not B: Aldolase cleaves the sugar without a redox cofactor.
Why not C: Pyruvate kinase performs direct phosphate transfer and does not use NAD⁺.
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Every NCERT question in this chapter is solved, free: NCERT solutions — Respiration in Plants →
Other NEET Biology chapters
The Living WorldBiological ClassificationPlant KingdomAnimal KingdomMorphology of Flowering PlantsAnatomy of Flowering Plants
All 32 chapters →
Questions
How many NEET questions are there on Respiration in Plants?
This chapter test has 30 questions — 10 easy, 14 medium and 6 hard — all written against the NCERT Class 11 chapter.
Is this NEET Biology chapter test free?
Yes. Every chapter test is free with no login. The only paid thing on the site is the full-length 90-question Biology mock and its all-India rank.
Do the questions explain the wrong options?
Yes — every distractor carries its own explanation naming the specific misconception that makes a student pick it. That is the part most question banks skip, and it is the part that changes your next attempt.