Respiration in Plants — NEET Botany video lectures, notes & PYQs

12 previous-year questions from this chapter every option and the correct answer, free · where the marks are

1. Glycolysis and fermentation

Exam focus: Glycolysis happens in the cytoplasm, not the mitochondrion, and runs identically whether the cell goes on to respire aerobically or ferment. Fermentation itself adds no extra ATP beyond glycolysis's own net 2 — its only job is regenerating NAD+ so glycolysis can keep going.

Respiration in Plants — Full Chapter

Competition Wallah

Full-chapter video with explicit chapter markers for glycolysis and fermentation, plus PYQs; bundled with the rest of the respiration chapter.

2. Krebs cycle and electron transport chain

Exam focus: FADH2 hands its electrons to the transport chain at Complex II, skipping Complex I entirely — which is exactly why it yields fewer ATP than NADH (2 versus 3, in the standard accounting) even though both are reduced coenzymes generated by the same turn of the cycle.

Respiration in Plants — Full Chapter

Competition Wallah

Same video; has dedicated chapter markers for the Krebs cycle, electron transport system, and chemiosmotic hypothesis.

BotanyNEET 2025show ▾

Complex II of the mitochondrial electron transport chain is also known as:

A.Cytochrome bc $_{1}$
B.Succinate dehydrogenase✓
C.Cytochrome c oxidase
D.NADH dehydrogenase

Solution

Complex II of the electron transport chain is succinate dehydrogenase, which passes electrons from $FAD H_{2}$ to ubiquinone. Complex I is NADH dehydrogenase, III the cytochrome bc $_{1}$ complex and IV cytochrome c oxidase.

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BotanyNEET 2024show ▾

Identify the step in the tricarboxylic acid cycle which does not involve oxidation of the substrate:

A.Succinic acid → Malic acid
B.Succinyl-CoA → Succinic acid✓
C.Isocitrate $\to α -$ ketoglutaric acid
D.Malic acid → Oxaloacetic acid

Solution

Succinyl-CoA → succinic acid is a substrate-level phosphorylation that releases CoA and makes GTP; no hydrogen is removed. The other three steps are dehydrogenations (oxidations).

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BotanyNEET 2024show ▾

Match List I with List II.

List I	List II
A. Citric acid cycle	I. Cytoplasm
B. Glycolysis	II. Mitochondrial matrix
C. Electron transport system	III. Intermembrane space of mitochondria
D. Proton gradient	IV. Inner mitochondrial membrane

Choose the correct answer from the options given below:

A.A-II, B-I, C-IV, D-III✓
B.A-III, B-IV, C-I, D-II
C.A-IV, B-III, C-II, D-I
D.A-I, B-II, C-III, D-IV

Solution

The citric acid cycle runs in the mitochondrial matrix (II); glycolysis in the cytoplasm (I); the electron transport system sits in the inner membrane (IV); protons are pumped into the intermembrane space to build the gradient (III).

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BotanyNEET 2023show ▾

Match List I with List II.

List I	List II
A. Oxidative decarboxylation	I. Citrate synthase
B. Glycolysis	II. Pyruvate dehydrogenase
C. Oxidative phosphorylation	III. Electron transport system
D. Tricarboxylic acid cycle	IV. EMP pathway

Choose the correct answer from the options given below:

A.A-III, B-IV, C-II, D-I
B.A-II, B-IV, C-I, D-III
C.A-III, B-I, C-II, D-IV
D.A-II, B-IV, C-III, D-I✓

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BotanyNEET 2023show ▾

Which of the following combinations is required for chemiosmosis?

A.Membrane, proton pump, proton gradient, ATP synthase✓
B.Membrane, proton pump, proton gradient, NADP synthase
C.Proton pump, electron gradient, ATP synthase
D.Proton pump, electron gradient, NADP synthase

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BotanyNEET 2021show ▾

Which of the following statements is incorrect?

A.During aerobic respiration, the role of oxygen is limited to the terminal stage
B.In the ETC (electron transport chain), one molecule of $NADH + H^{+}$ gives rise to 2 ATP molecules, and one $FAD H_{2}$ gives rise to 3 ATP molecules✓
C.ATP is synthesised through complex V
D.Oxidation–reduction reactions produce a proton gradient in respiration

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BotanyNEET 2020show ▾

The number of substrate-level phosphorylations in one turn of the citric acid cycle is:

A.Zero
B.One✓
C.Two
D.Three

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3. Respiratory quotient and amphibolic pathway

Exam focus: RQ reveals what's being burned: carbohydrate respiration gives RQ = 1, fat gives RQ below 1 (oxidising its extra hydrogen needs more O2 than the CO2 released), and organic acids give RQ above 1. Respiration is also amphibolic, not purely catabolic — its intermediates are routinely drawn off to build fats and amino acids too.

Respiration in Plants — Full Chapter

Competition Wallah

Same video; has explicit chapter markers for the amphibolic pathway and respiratory quotient near the end.