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NEET Respiration in Plants: 5 practice MCQs with answers

By the PrepMatic team · Updated 9 Oct 2026 · 3 min read

Respiration in Plants covers how cells release energy from food: glycolysis, fermentation, the Krebs cycle and the electron transport system. It is a Class 11 Biology chapter in which many questions ask about counts, locations and products. The five MCQs below test the net ATP of glycolysis, the respiratory quotient, the first step of the Krebs cycle, the final electron acceptor and a step in fermentation.

What this chapter covers in the NEET syllabus

Respiration is a topic in the NMC unit Plant Physiology and in NCERT it is the Class 11 chapter Respiration in Plants. The topics are:

• Cellular respiration: glycolysis in the cytoplasm.
• Fermentation, and aerobic respiration with the link reaction.
• The tricarboxylic acid (TCA or Krebs) cycle.
• The electron transport system and oxidative phosphorylation.
• The respiratory balance sheet, the amphibolic pathway and the respiratory quotient.

Five practice MCQs on Respiration in Plants

Question 1

The net gain of ATP molecules in glycolysis, per glucose molecule, is:

• A. 4
• B. 2
• C. 8
• D. 38

Question 2

The respiratory quotient (RQ) when fats are the respiratory substrate is about:

• A. 0.7
• B. 1.0
• C. 0.9
• D. zero

Question 3

In the Krebs cycle, acetyl CoA condenses with oxaloacetic acid to form:

• A. succinic acid
• B. malic acid
• C. citric acid
• D. pyruvic acid

Question 4

The final acceptor of electrons in the electron transport system of aerobic respiration is:

• A. NAD⁺
• B. cytochrome c
• C. FAD
• D. molecular oxygen

Question 5

In alcoholic fermentation, CO₂ is released when:

• A. glucose is phosphorylated to glucose-6-phosphate
• B. pyruvic acid is converted to acetaldehyde
• C. acetaldehyde is reduced to ethanol
• D. glyceraldehyde-3-phosphate is oxidised

Answers and explanations

1. B. Glycolysis uses 2 ATP in its early steps and makes 4 ATP by substrate-level phosphorylation later, a net gain of 2 ATP. It also gives 2 NADH and 2 pyruvic acid molecules.
2. A. RQ is the ratio of CO₂ released to O₂ consumed. For carbohydrates it is 1, for proteins about 0.9, and for fats about 0.7, because fats contain less oxygen and need more O₂ to be oxidised.
3. C. Acetyl CoA (2 carbons) condenses with oxaloacetic acid (4 carbons) to give citric acid (6 carbons), and the enzyme is citrate synthase. This is why the cycle is also called the citric acid cycle.
4. D. Electrons pass through complexes I to IV, and at complex IV (cytochrome c oxidase) they reduce oxygen to water. Oxygen is the terminal acceptor, which is why respiration stops if oxygen is absent.
5. B. Pyruvic acid is decarboxylated by pyruvic acid decarboxylase to give acetaldehyde and CO₂. Acetaldehyde is then reduced to ethanol by alcohol dehydrogenase, which regenerates NAD⁺ without releasing more CO₂.

How to prepare Respiration in Plants

• Track each stage in a table: where it occurs, the substrate, the products (ATP, NADH, FADH₂, CO₂) and the enzymes NCERT names. The Krebs cycle takes place in the mitochondrial matrix, and ETS on the inner membrane.
• Learn the key steps of the TCA cycle as a loop: citrate, isocitrate, α-ketoglutarate, succinyl CoA, succinate, fumarate, malate, oxaloacetate. Mark the steps that release CO₂ and the ones that make NADH, FADH₂ and GTP or ATP.
• Know the counts, and where NCERT differs from other books. Total ATP yield per glucose differs between books because of the assumptions made. Follow the numbers in your NCERT edition and treat them as theoretical maxima.
• Compare aerobic and anaerobic respiration: energy yield, products, organisms. Remember that yeast ferments to ethanol and CO₂, and muscle cells make lactic acid.
• Draw a diagram of the amphibolic pathway, showing how fats, proteins and carbohydrates feed into the cycle.

Study this chapter next to Photosynthesis, since they are the two big energy chapters of plant physiology. The NEET Biology preparation guide has the chapter order, and the NEET syllabus lists every unit.

Take a full Respiration in Plants test on PrepMatic

Respiration is full of counts and locations that are easy to blur, so test yourself against a timer. A PrepMatic topic test is about 15 questions in 30 minutes and uses NEET's negative marking. The free Basic plan includes topic tests, and more chapters are on the practice hub.

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