Respiration in Plants is a fundamental chapter in Class 11 Biology that explains how plants break down food to release energy. Unlike animals, plants respire at a cellular level through processes such as glycolysis, the Krebs cycle, and oxidative phosphorylation. This topic is essential for NEET as it builds the foundation of cellular respiration and bioenergetics. Practicing NEET MCQs Respiration in Plants helps students master key concepts like aerobic and anaerobic respiration, energy yield, respiratory quotient (RQ), and the role of mitochondria.

These MCQs are designed to test both factual knowledge and application-based understanding, making them a crucial part of NEET preparation.

NEET MCQs Respiration in Plants

In the electron transport system present in the inner mitochondrial membrane, complexes I and IV are
respectively
a) NADH Dehydrogenase and FADH2
b) NADH2 and NADH Dehydrogenase
c) NADH Dehydrogenase and cytochrome-c oxidase complex
d) NADH dehydrogenase and ATP synthase
In respiration incomplete oxidation of glucose is done under
a) Aerobic respiration b) Anaerobic respiration
c) Both (a) and (b) d) None of these
The cellular respiration first takes place in the
a) Cytoplasm b) Golgi bodies c) ER d) Lysosomes
Which of the following scientist has given the scheme of glycolysis?
a) Gustav Embden et. al b) Kreb et. al c) Fritz Lipmann et. al d) None of these
Which metabolic pathway is a common pathway to both anaerobic and aerobic metabolism?
a) Glycolysis b) EMP pathway c) Both (a) and (b) d) None of the above
In mitochondria, enzyme cytochrome oxidase is present in
a) Outer membrane b) Perimitochondrial space
c) Inner membrane d) Matrix
TCA cycle enzymes are present in
a) Cytoplasm b) Inter membrane space of mitochondria
c) Mitochondrial matrix d) Inner membrane of mitochondria
Among the following, identify the substrate required for the only oxidative reaction that occurs in the
process of glycolysis.
a) 3-phosphoglyceric acid
b) Glyceraldehyde 3-phosphate
c) Fructose-6-phosphate
d) Glucose-6-phosphate
Aerobic respiration is
a) The process in which complete oxidation of organic substances in the absence of oxygen
b) The process in which complete oxidation of organic substances in the presence of oxygen
c) The process in which incomplete oxidation of organic substances in the absence of oxygen
d) The process in which incomplete oxidation of organic substances in the presence of oxygen
What will happen, when glucose is administered orally?
a) Excretion b) Digestion c) Circulation d) Respiration
How many ATP molecules could maximally be generated from one molecule of glucose, if the complete
oxidation of one mole of glucose to carbon dioxide and water yields 686 kcal and the useful chemical
energy available in the high energy phosphate bond of one mole of ATP is 12 kcal?
a) Two b) Thirty c) Fifty seven d) One
In photosynthesis, NADPH2 is formed but in respiration it forms during
a) HMP b) ETS c) Krebs’ cycle d) None of these

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13.Plants does not need specialised respiratory organ because

a) Each plant part takes care of its own gas exchange
needs
b) Plants do not need great demands for gas
exchange
c) Both (a) and (b) d) None of the above

Lactic acid is formed in
a) Fermentation b) Glycolysis c) HMP pathways d) None of these
In which part of mitochondria does ATP synthesis occur?
a) F1 b) F0
c) Cristae d) Inner membrane of mitochondria
In oxidative decarboxylation, enzyme used to
a) Pyruvate decarboxylase b) Pyruvate dehydrogenase
c) Pyruvate hydrogeneticase d) Pyruvate dehydrogeneticase
Select the wrong statement.
a) When tripalmitin is used as a substrate in respiration, the RQ is 0.7
b) The intermediate compound which links glycolysis with Krebs’ cycle is malic acid
c) One glucose molecule yields a net gain of 36 ATP molecules during aerobic fermentation
d) One glucose molecule yields a net gain of 2 ATP molecules during fermentation
Enzymes found attached to inner membrane of mitochondria instead of matrix is/are
a) Succinic Dehydrogenase b) Cytochrome oxidase
c) Both (a) and (b) d) Malic Dehydrogenase
Four respiratory enzymes are given below. Arrange them in increasing order of the carbon number of the
substrates on which they act.
I. Enolase
II. Aconitase
III. Fumarase
IV. Alcohol Dehydrogenase
a) II, IV, III, I b) IV, I, II, III c) I, IV, III, II d) IV, I, III, II
Link enzyme in cellular respiration is
a) Citrate synthetase b) Pyruvate Dehydrogenase
c) Isocitrate Dehydrogenase d) Succinyl thiokinase
Beer and butter milk are products of fermentation by
a) Rhizopus stolonifer b) Caedobacter taeniospiralis
c) Bacillus subtilis d) Saccharomyces cerevisiae
Apparatus to measure rate of respiration and respiratory quotient is
a) Auxanometer b) Potometer c) Respirometer d) Manometer
Acetyl Co-A binds to oxaloacetic acid to form
a) Formaldehyde b) Citrate c) Acetate d) Isocitrate
In fermentation NADH is oxidised to NAD+ in ….. rate
a) Fast b) Slow c) Usual d) None of these
Last electron acceptor in respiration is
a) Oxygen b) Hydrogen c) Carbon dioxide d) NADH
In animal cells, like muscle, during exercise when O2 is inadequate for cellular respiration, pyruvic acid is
reduced into lactic acid by
a) O2 b) Carboxylation
c) Lactate dehydrogenase d) None of the above
Glucose break down takes place ….. in fermentation
a) Partially b) Completely
c) According to substrate d) None of these
Plants need one of the following for ATP formation
a) N and P b) N and Cu c) N and Ca d) K
First vitamin to be produced through fermentation process using a wild bacterium was

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a) Vitamin-D b) Vitamin-C c) Vitamin- B12 d) Vitamin-B2

Fate of pyruvic acid during aerobic respiration is
a) Lactic acid fermentation b) Alcoholic acid fermentation
c) Oxidative decarboxylation d) Oxidative phosphorylation
In respiration, respiratory substances can be used
a) Carbohydrate b) Protein c) Organic acid d) All of these
In oxidative decarboxylation, only a carbon molecule of pyruvic acid is get oxidised, other two carbon
molecule goes to form
a) Acetyl Co-A b) CO2 c) Citric acid d) Both (a) and (b)
Enzymes of electron transport system are present in
a) Inner mitochondrial membrane b) Matrix
c) Intermembranous space d) Endoplasmic reticulum
Fungi are dependent on dead and decaying matter for feeding, it is called
a) Saprophytes b) Halophytes c) Xerophytes d) Nanophytes
Which of the following reaction does not take place in the cell organelle, that is referred to as ‘Power house
of the cell’?
a) Glycine Decarboxylation b) Glyceraldehyde 3-phosphate dehydrogenation
c) Fumaric acid hydration d) Cytochrome oxidation
Which of the following is true regarding glycolysis?
I. Takes place in cytosol
II. Produces no ATP
III. Has no connection with electron transport chain
IV. Reduces two molecules of NAD+ for every glucose molecule processed
Choose the correct option
a) Only I b) I, II and III c) I and II d) None of these
The reaction which is catalysed by a protein that is not found in the matrix of mitochondria is
a) Conversion of pyruvic acid to acetyl coenzyme-A b) Oxidative Decarboxylation of 𝛼-ketoglutaric acid
c) Oxidation of Succinic acid d) Cleavage of Succinyl coenzyme-A
All enzymes of TCA cycle are located in the mitochondrial matrix except one, which is located in inner
mitochondrial membranes in eukaryotes and in cytosol in prokaryotes. This enzyme is
a) Lactate Dehydrogenase b) Isocitrate Dehydrogenase
c) Malate Dehydrogenase d) Succinate Dehydrogenase
Identify enzyme A in the given reaction of Kreb’s cycle
OAA+Acetyl Co−A+H2O A → Citric acid + Co – A
a) Oxaloacetate synthetase b) Citrate synthetase
c) Aconitase d) Dehydrogenase
The enzymes for TCA cycle are present in
a) Plastids b) Golgi complex
c) Mitochondria d) Endoplasmic reticulum
Which one of the following is the terminal electron acceptor?
a) Molecular CO2 b) Molecular O2 c) Molecular H2 d) NADPH2
In electron transport system, which of the following acts as a final hydrogen acceptor
a) Oxygen b) Hydrogen c) Calcium d) Ubiquinone
If a starving plant is provided with glucose, the rate of respiration would
a) First rise then fall b) Become constant c) Decrease d) Increase
Which one is product of aerobic respiration?
a) Malic acid b) Ethyl alcohol c) Lactic acid d) Pyruvic acid
Given below the diagrammatic presentation of ATP synthesis in mitochondria. Identify A-C and Choose the
correct option accordingly

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a) A−H+,B−F1,C−F0 b) A−3H+,B−F0,C−F1
c) A−2H+,B−F0,C−F1 d) A−5H+,B−F1,C−F0

In Krebs’ cycle,
a) ADP is converted into ATP
b) Pyruvic acid is converted into CO2 and H2O
c) Glucose is converted into CO2
d) Pyruvic acid is converted into ATP
Decline in the activity of the enzyme Hexokinase by glucose-6-phosphate is caused by
a) Non-competitive
b) Competitive inhibitors
c) Allosteric modulators
d) Denaturation of enzyme
In which of the following reactions of glycolysis, oxidation takes place?
a) Glucose 6-PO4 to fructose 6-PO4
b) Glyceraldehydes 3-phosphate to 1, 3-diphosphoglycerate
c) 1,3-diphosphoglycerate to 3-phosphoglycerate
d) 2-phosphoglycerate to phosphoglycerate
During conversion of pyruvic acid into acetyl Co-A, pyruvic acid is
a) Oxidized b) Reduced c) Isomerized d) Condensed
During anaerobic respiration in yeast
a) 𝐻2𝑂 and 𝐶𝑂2 are end-products
b) 𝐶𝑂2 , ethanol and energy are end-products
c) 𝐶𝑂2 , and H2O are end-products
d) 𝐶𝑂2 , acetic acid and energy are end-products
Choose the correct combination of A and B according to NCERT text book.
All living organisms need …A… for carrying out daily life activities and is obtained by …B… of
macromolecules
a) A-oxygen; B-reduction b) A-energy; B-reduction
c) A-energy; B-oxidation d) A-oxygen; B-oxidation
Most of the biological energy is supplied by mitochondria through
a) Breaking of proteins b) Reduction of NADP+
c) Breaking of sugars d) Oxidising TCA (tricarboxylic acid) substrate
Chemiosmotic mechanism of ATP production in aerobic respiration was given by
a) Krebs b) Calvin c) Hatch and Slack d) Peter Mitchell
Choose the correct combination of labeling the molecules involved in the pathway of anaerobic respiration
in yeast

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a) A – Ethanol, B – CO2 , C – Acetaldehyde
b) A – CO2 , B – Ethanol, C- Acetaldehyde
c) A – CO2, B – Acetaldehyde, C- Ethanol
d) A – Ethanol, B – Acetaldehyde, C – CO2

Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and
proteins?
a) Glucose-6-phosphate b) Fructose, 6-bisphosphate
c) Pyruvic acid d) Acetyl Co-A
In succulent plants like Opuntia, the RQ value will be
a) Less than one b) More than one c) Infinite d) Zero
The pyruvic acid formed during glycolysis is oxidized to CO2 and H2O in a cycle called
a) Calvin cycle b) Nitrogen cycle c) Hill reaction d) Krebs’ cycle
Respiratory enzymes are present in the following organelle
a) Peroxisome b) Chloroplast c) Mitochondrion d) Lysosome
An ATP molecule is structurally most similar to a molecule of
a) RNA nucleotide b) DNA nucleotide c) Amino acid d) Fatty acid
Read the following and choose the option containing correct pair
I. DCMU Herbicide Inhibitor of non-cyclic electron transport
II. PMA Fungicide Reduce transpiration
III. Colchicine Alkaloid Causes male sterility
IV. Soilrite Sodium alginate Encapsulation of somatic embryos
a) I and II b) I and III c) II and III d) II and IV
Oxidation of one molecule of NADH gives rise to
a) 3 ATP molecules b) 12 ATP molecules c) 2 ATP molecules d) 1ATP molecule
Aerobic respiratory pathway is appropriately termed as
a) Catabolic b) Parabolic c) Amphibolic d) Anabolic
In alcohol fermentation,
a) There is no electron donor
b) Oxygen is the electron acceptor
c) Triose phosphate is the electron donor, while acetaldehyde is the electron acceptor
d) Triose phosphate is the electron donor, while pyruvic acid is the electron acceptor
In respiration breaking down of glucose with oxygen is known as
a) Oxidation process b) Reduction process
c) Oxidation-oxaloacitation process d) All of the above
Net gain of ATP molecules per hexose during aerobic respiration is
a) 12 b) 18 c) 36 d) 30
Which of these are respiratory poisons or inhibitors of electron transport chain?
a) Cyanides b) Antimycin-A c) Carbon monoxide d) All of these
Kreb’s cycle is completed with the formation of
a) Citric acid b) Oxaloacetic acid (OAA)
c) Succinic acid d) Malic acid

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Where is ATP synthesised in glycolysis?
a) When 1, 3 di PGA is changed into 3PGA
b) When glucose is converted into glucose-6-phosphate
c) Both (a) and (b)
d) When, 1, 6 diphosphate is broken in triose phosphate
Maximum number of ATP is obtained from
a) Glucose b) Palmitic acid c) Malic acid d) 𝛽-amino acid
Glycolysis takes place in
a) All living cells b) Eukaryotic cells only
c) Prokaryotic cells only d) None of these
Krebs’ cycle begins with the reaction
a) Citric acid +acetyl Co-A b) Oxaloacetic acid + pyruvic acid
c) Oxaloacetic acid + citric acid d) Oxaloacetic acid + acetyl Co-A
Co-Factor required for formation of acetyl Co-A is
a) TPP b) Lipoic acid c) Mg2+, Co-A d) All of these
In anaerobic respiration in plants
a) Oxygen is absorbed b) Oxygen in released
c) Carbon dioxide is released d) Carbon dioxide is absorbed
The respiratory quotient (RQ) of some of the compounds are 4,1 and 0.7. These compounds are identified
respectively as
a) Malic acid, palmitic acid and tripalmitin b) Oxalic acid, carbohydrate and tripalmitin
c) Tripalmitin, malic acid and carbohydrate d) Palmitic acid, carbohydrate and oxalic acid
The enzyme ….. is used to catalysed when condensation of acetyl group with oxaloacetic acid and to yield
citric acid
a) Citrate permeate b) citrate synthase c) Citrate burate d) Citrate maliate
The respiratory quotient (RQ) of a germinating castor seed is
a) Equal to one b) Greater than one c) Less than one d) Equal to zero
Glycolysis
I. causes partial oxidation of glucose (one molecule) to form 2-molecules of pyruvic acid and 2 ATP as net
gain
II. takes place in all living cells
III. uses 2 ATP at two steps
IV. scheme was given by Gustav Embden, Otto Mayerhof and J Parnas
Choose the correct option containing appropriate statements from the above
a) I, II and III b) I, II and IV c) I, II, III and IV d) Only I
During oxidative phosphorylation, the net gain of ATP is
a) 40 b) 38 c) 34 d) 30
Decarboxylation is involved in
a) Electron transport system
b) Glycolysis
c) Krebs’ cycle
d) Lactic acid fermentation
Alternate name of TCA cycle is
a) Kreb’s cycle b) Grab’s cycle c) Mayerhoff cycle d) Embden cycle
A businessman of 80 kg weight requires 4800 kcal energy daily. How many ATP molecules and glucose
molecules does he require to produce this much energy?
a) 20 molecules of glucose and 384 molecules of ATP
b) 40 molecules of glucose and 264 molecules of ATP
c) 18 molecules of glucose and 657 molecules of ATP
d) 20 molecules of glucose and 460 molecules of ATP

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