Question 1: Palette 1/46

NEET 2026 MCQ

$ 2\left(\mathrm{C}_{51} \mathrm{H}_{98} \mathrm{C}_6\right)+145 \mathrm{O}_2 \rightarrow 102 \mathrm{CO}_2+98 \mathrm{H}_2 \mathrm{O}+\text { energy } $

The Respiratory Quotient (RQ) of a biomolecule used for respiration, as per the above equation would be :

A

Between 0.5 and 0.95

B

Less than 0.5

C

1.0

D

Between 1.25 and 2

Question 2: Palette 2/46

NEET 2026 MCQ

$ \text { Match List-I with List-II: } $

$ \text { List-I (Process) } $		$ \text { List-II (Location) } $
A.	Glycolysis	I.	Inner mitochondrial membrane
B.	ETS	II.	Mitochondrial matrix
C.	Accumulation of protons	III.	Cytoplasm
D.	Krebs' cycle	IV.	Intermembrane space

Choose the correct answer from the options given below:

A

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

B

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

C

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

D

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

Question 3: Palette 3/46

NEET 2026 MCQ

How many molecules of pyruvic acid are produced at the end of glycolysis from 206 molecules of glucose?

A

412

B

206

C

309

D

103

Question 4: Palette 4/46

NEET 2025 MCQ

The complex II of mitochondrial electron transport chain is also known as

A

Cytochrome c oxidase

B

NADH dehydrogenase

C

Cytochrome $\mathrm{bc}_1$

D

Succinate dehydrogenase

Question 5: Palette 5/46

NEET 2024 MCQ

Match List-I with List-II:

	List - I		List - II
(A)	ETS Complex I	(I)	NADH Dehydrogenase
(B)	ETS Complex II	(II)	Cytochrome bC$_1$
(C)	ETS Complex III	(III)	Cytochrome C oxidase
(D)	ETS Complex IV	(IV)	Succinate Dehydrogenase

Choose the correct answer from the options given below :

A

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

B

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

C

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

D

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

Question 6: Palette 6/46

NEET 2024 MCQ

Which of the following are correct about cellular respiration?

A. Cellular respiration is the breaking of C-C bonds of complex organic molecules by oxidation.

B. The entire cellular respiration takes place in Mitochondria.

C. Fermentation takes place under anaerobic condition in germinating seeds.

D. The fate of pyruvate formed during glycolysis depends on the type of organism also.

E. Water is formed during respiration as a result of O$_2$ accepting electrons and getting reduced.

Choose the correct answer from the options given below :

A

A, C, D, E only

B

A, B, E only

C

A, B, C, E only

D

B, C, D, E only

Question 7: Palette 7/46

NEET 2024 MCQ

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-I, B-II, C-III, D-IV

B

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

C

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

D

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

Question 8: Palette 8/46

NEET 2024 MCQ

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

A

Malic acid $\rightarrow$ Oxaloacetic acid

B

Succinic acid $\rightarrow$ Malic acid

C

Succinyl-CoA $\rightarrow$ Succinic acid

D

Isocitrate $\rightarrow \alpha$-ketoglutaric acid

Question 9: Palette 9/46

NEET 2023 MCQ

How many times decarboxylation occurs during each TCA cycle?

A

Thrice

B

Many

C

Once

D

Twice

Question 10: Palette 10/46

NEET 2023 MCQ

Fatty acids are connected with the respiratory pathway through :

A

Acetyl CoA

B

$\alpha$-Ketoglutaric acid

C

Dihydroxy acetone phosphate

D

Pyruvic acid

Question 11: Palette 11/46

NEET 2023 MCQ

Given below are two statements : One is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : ATP is used at two steps in glycolysis.

Reason R : First ATP is used in converting glucose into glucose-6-phosphate and second ATP is used in conversion of fructose-6-phosphate into fructose-1, 6-diphosphate.

In the light of the above statements, choose the correct answer from the options given below :

A

Both A and R are true but R is NOT the correct explanation of A.

B

A is true but R is false.

C

A is false but R is true.

D

Both A and R are true and R is the correct explanation of A.

Question 12: Palette 12/46

NEET 2023 MCQ

Which of the following combinations is required for chemiosmosis?

A

Membrane, proton pump, proton gradient, NADP synthase

B

Proton pump, electron gradient, ATP synthase

C

Proton pump, electron gradient, NADP synthase

D

Membrane, proton pump, proton gradient, ATP synthase

Question 13: Palette 13/46

NEET 2023 MCQ

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 – II, B – IV, C – I, D – III

B

A – III, B – I, C – II, D – IV

C

A – II, B – IV, C – III, D – I

D

A – III, B – IV, C – II, D – I

Question 14: Palette 14/46

NEET 2023 MCQ

Melonate inhibits the growth of pathogenic bacteria by inhibiting the activity of

A

Amylase

B

Lipase

C

Dinitrogenase

D

Succinic dehydrogenase

Question 15: Palette 15/46

NEET 2022 MCQ

The number of time(s) decarboxylation of isocitrate occurs during single TCA cycle is

A

Four

B

One

C

Two

D

Three

Question 16: Palette 16/46

NEET 2022 MCQ

What is the net gain of ATP when each molecule of glucose is converted to two molecules of pyruvic acid?

A

Four

B

Six

C

Two

D

Eight

Question 17: Palette 17/46

NEET 2022 MCQ

What amount of energy is released from glucose during lactic acid fermentation?

A

Approximately 15%

B

More than 18%

C

About 10%

D

Less than 7%

Question 18: Palette 18/46

NEET 2022 MCQ

The 5-C compound formed during TCA cycle is

A

Fumaric acid

B

$\alpha$-ketoglutaric acid

C

Oxalo succinic acid

D

Succinic acid

Question 19: Palette 19/46

NEET 2021 MCQ

Which of the following statements is incorrect?

A

Oxidation-reduction reactions produce proton gradient in respiration

B

During aerobic respiration, role of oxygen is limited to the terminal stage.

C

In ETC (Electron Transport Chain), one molecule of NADH + H⁺ gives rise to 2 ATP molecules, and one FADH₂ gives rise to 3 ATP molecules

D

ATP is synthesized through complex V

Question 20: Palette 20/46

NEET 2020 MCQ

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

A

Zero

B

One

C

Three

D

Two

Question 21: Palette 21/46

NEET 2019 MCQ

Conversion of glucose to glucose-6 phosphate, the first irreversible reaction of glycolysis, is catalyzed by

A

Enolase

B

Phosphofructokinase

C

Aldolase

D

Hexokinase

Question 22: Palette 22/46

NEET 2019 MCQ

Respiratory Quotient (RQ) value of tripalmitin is :

A

0.07

B

0.09

C

0.9

D

0.7

Question 23: Palette 23/46

NEET 2018 MCQ

Which of these statements is incorrect?

A

Glycolysis operates as long as it is supplied with NAD that can pick up hydrogen atoms.

B

Enzymes of TCA cycle are present in mitochondrial matrix.

C

Oxidative phosphorylation takes place in outer mitochondrial membrane.

D

Glycolysis occurs in cytosol.

Question 24: Palette 24/46

NEET 2018 MCQ

What is the role of NAD⁺ in cellular respiration?

A

It is the final electron acceptor for anaerobic respiration.

B

It functions as an enzyme.

C

It functions as an electron carrier.

D

It is a nucleotide source for ATP synthesis.

Question 25: Palette 25/46

NEET 2017 MCQ

Which statement is wrong for Krebs' cycle?

A

There is one point in the cycle where FAD⁺ is reduced to FADH₂.

B

During conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised.

C

The cyclic starts with condensation of acetyl group (acetyl CoA) with pyruvic acid to yield citric acid.

D

There are three points in the cycle where NAD⁺ is reduced to NADH + H⁺.

Question 26: Palette 26/46

NEET 2016 MCQ

Oxidative phosphorylation is

A

formation of ATP by transfer of phosphate group from a substrate to ADP

B

oxidation of phosphate group in ATP

C

addition of phosphate group to ATP

D

formation of ATP by energy released from electrons removed during substrate oxidation.

Question 27: Palette 27/46

NEET 2016 MCQ

Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins?

A

Glucose-6-phosphate

B

Fructose 1, 6-bisphosphate

C

Pyruvic acid

D

Acetyl CoA

Question 28: Palette 28/46

NEET 2015 MCQ

Cytochromes are found in

A

cristae of mitochondria

B

lysosomes

C

matrix of mitochondria

D

outer wall of mitochondria.

Question 29: Palette 29/46

NEET 2014 MCQ

In which one of the following processes CO₂ is not released?

A

Aerobic respiration in plants

B

Areobic respiration in animals

C

Alcoholic fermentation

D

Lactic fermentation

Question 30: Palette 30/46

NEET 2013 MCQ

The three boxes in this diagram represent the three major biosynthetic pathway in aerobic respiration. Arrows represent net reactants or products.


Arrows numbered 4, 8 and 12 can all be

A

H₂O

B

FAD⁺ or FADH₂

C

NADH

D

ATP.

Question 31: Palette 31/46

NEET 2013 MCQ

Which of the metabolites is common to respiration-mediated breakdown of fats, carbohydrates and proteins?

A

Pyruvic acid

B

Acetyl CoA

C

Glucose- 6 - phosphate

D

Fructose 1, 6 - bisphosphate

Question 32: Palette 32/46

NEET 2011 MCQ

In mitochondria, protons accumulate in the

A

outer membrane

B

inner membrane

C

intermembrane space

D

matrix

Question 33: Palette 33/46

NEET 2010 MCQ

The energy-releasing metabolic process in which substrate is oxidised without an external electron acceptor is called

A

glycolysis

B

fermentation

C

aerobic respiration

D

photorespiration.

Question 34: Palette 34/46

NEET 2009 MCQ

Aerobic respiratory pathway is appropriately termed

A

parabolic

B

amphibolic

C

anabolic

D

etabolic.

Question 35: Palette 35/46

NEET 2008 MCQ

The chemiosmotic coupling hypothesis of oxidative phosphorylation proposes that adenosine triphosphate (ATP) is formed because

A

a proton gradient forms across the inner membrane

B

there is a change in the permeability of the inner mitochondrial membrane toward adenosine diphosphate (ADP)

C

high energy bonds are formed in mitochondrial proteins

D

ADP is pumped out of the matrix into the intermembrane space.

Question 36: Palette 36/46

NEET 2008 MCQ

The energy-releasing metabolic process in which substrate is oxidised without an external electron acceptor is called

A

glycolysis

B

fermentation

C

aerobic respiration

D

photorespiration

Question 37: Palette 37/46

NEET 2007 MCQ

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

isocitrate dehydrogenase

B

malate dehydrogenase

C

succinate dehydrogenase

D

lactate dehydrogenase.

Question 38: Palette 38/46

NEET 2007 MCQ

The overall goal of glycolysis, Krebs' cycle and the electron transport system is the formation of

A

ATP in one large oxidation reaction

B

sugars

C

nucleic acids

D

ATP in small stepwise units.

Question 39: Palette 39/46

NEET 2006 MCQ

How many ATP molecules could maximally be generated from one molecule of glucose, if the complete oxidation of one mole of glucose to CO₂ and H₂O yields 686 kcal and the useful chemical energy available in the high energy phosphate bond of one mole of ATP is 12 kcal?

A

1

B

2

C

30

D

57

Question 40: Palette 40/46

NEET 2005 MCQ

During which stage in the complete oxidation of glucose are the greatest number of ATP molecules formed from ADP?

A

Glycolysis

B

Krebs' cycle

C

Conversion of pyruvic acid to acetyl CoA

D

Electron transport chain

Question 41: Palette 41/46

NEET 2004 MCQ

In glycolysis, during oxidation electrons are removed by

A

ATP

B

glyceraldehyde-3-phosphate

C

NAD⁺

D

molecular oxygen.

Question 42: Palette 42/46

NEET 2003 MCQ

In alcohol fermentation

A

triose phosphate is the electron donar while acetaldehyde is the electron acceptor

B

triose phosphate is the electron donar while pyruvic acid is the electron acceptor

C

there is no electron donar

D

oxygen is the electron acceptor.

Question 43: Palette 43/46

NEET 2003 MCQ

In which one of the following do the two names refer to one and same thing?

A

Krebs' cycle and Calvin cycle

B

Tricarboxylic acid cycle and citric acid cycle

C

Citric acid cycle and Calvin cycle

D

Tricarboxylic acid cycle and urea cycle

Question 44: Palette 44/46

NEET 2002 MCQ

Organisms which obtain energy by the oxidation of reduced inorganic compounds are called

A

photoautotrophs

B

chemoautotrophs

C

saprozoic

D

coproheterophs.

Question 45: Palette 45/46

NEET 2002 MCQ

How many ATP molecules are produced by aerobic oxidation of one molecule of glucose?

A

2

B

4

C

38

D

34

Question 46: Palette 46/46

NEET 2001 MCQ

Cytochrome is

A

metallo flavo protein

B

Fe containing porphyrin pigment

C

glycoprotein

D

lipid.