Free NEET Biology multiple-choice questions on Cellular Respiration. Attempt each question and reveal the answer with a full explanation.
How many molecules of CO 2 are released during one complete turn of the Krebs cycle? 2 1 3 4 What is the role of NAD + in cellular respiration? It is a nucleotide source for ATP synthesis. It functions as an electron carrier. It functions as an enzyme. It is the final electron acceptor for anaerobic respiration. The final electron acceptor in the mitochondrial Electron Transport System is: Oxygen Cytochrome c NADPH Water The enzymatic complex 'Pyruvate Dehydrogenase', which converts Pyruvate to Acetyl CoA, is located in the: Mitochondrial matrix Inner mitochondrial membrane Peroxisome Cytoplasm During the Link Reaction (Oxidative decarboxylation), for every two molecules of Pyruvate entering the mitochondria, the net yield of NADH and CO 2 is: 2 NADH and 2 CO 2 1 NADH and 1 CO 2 4 NADH and 2 CO 2 2 NADH and 4 CO 2 In the Citric Acid Cycle, how many total molecules of NADH + H + are produced from the complete oxidation of one molecule of Acetyl CoA? Three Two Four Six The respiratory quotient (RQ) of pure carbohydrates under aerobic conditions is: 1.0 0.7 0.9 More than 1.0 In the mitochondrial Electron Transport System (ETS), Complex III is also known as: Cytochrome bc 1 complex NADH dehydrogenase complex Succinate dehydrogenase complex Cytochrome c oxidase complex During the process of glycolysis, what is the net yield of NADH + H + per molecule of glucose? 2 4 1 0 The F 1 headpiece of the ATP synthase complex, where the actual catalytic site for ATP synthesis is located, is also known as: Oxysomes Polysomes Mesosomes Centrosomes In fermentation by yeast, the cells effectively poison themselves to death when the concentration of alcohol reaches approximately: 13% 7% 25% 5% For every molecule of FADH 2 oxidized through the Electron Transport System (ETS), how many molecules of ATP are generated? 2 ATP 3 ATP 1 ATP 4 ATP Which of these statements is incorrect? Glycolysis operates as long as it is supplied with NAD that can pick up hydrogen atoms Glycolysis occurs in cytosol Enzymes of TCA cycle are present in mitochondrial matrix Oxidative phosphorylation takes place in outer mitochondrial membrane The conversion of Glucose to Glucose-6-Phosphate in the first step of glycolysis is an endergonic reaction that consumes how many ATP molecules? 1 ATP 2 ATP 0 ATP 4 ATP The respiratory quotient (RQ) of tripalmitin, a common fat, is approximately: 0.7 1.0 0.9 1.3 The net gain of ATP molecules from the complete oxidation of one molecule of glucose through aerobic respiration is: 36 to 38 ATP 2 ATP 4 ATP 12 ATP Which enzyme is responsible for the conversion of Pyruvic acid to Acetyl CoA? Pyruvate dehydrogenase Hexokinase Phosphofructokinase Citrate synthase In the Electron Transport System, Complex IV is also known as: Cytochrome c oxidase NADH dehydrogenase Succinate dehydrogenase ATP synthase Which hormone, released by the hypothalamus, inhibits the release of Growth Hormone from the pituitary? Somatostatin Somatotropin Gonadotropin Oxytocin The secretion of which of the following is inhibited by the hormone Somatostatin produced by the hypothalamus? Growth Hormone Thyroid Stimulating Hormone Prolactin Oxytocin 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 ? Two Thirty Fifty-seven One 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 isocitrate dehydrogenase malate dehydrogenase succinate dehydrogenase lactate dehydrogenase. The three boxes in this diagram represent the three major biosynthetic pathways in aerobic respiration. Arrows represent net reactants or products. Arrows numbered 4, 8, and 12 can all be NADH ATP H2O FAD+ or FADH2 Conversion of glucose to glucose-6-phosphate, the first irreversible reaction of glycolysis, is catalyzed by Phosphofructokinase Aldolase Hexokinase Enolase Which of the metabolites is common to respiration mediated breakdown of fats, carbohydrates and proteins? Glucose-6-phosphate Fructose 1,6-bisphosphate Pyruvic acid Acetyl CoA Which of the following values will depict correct respiratory quotient when tripalmitin (a fatty acid) is used as a respiratory substrate? 1.1 1 0.7 0.9 Respiratory Quotient (RQ) value of tripalmitin is (1) 0.09 (2) 0.9 (3) 0.7 (4) 0.07 Match List I with List II : array ll 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 array Choose the correct answer from the options given below : A – III, B – IV, C – II, D – I A – II, B – IV, C – I, D – III A – III, B – I, C – II, D – IV A – II, B – IV, C – III, D – I Identify the step in tricarboxylic acid cycle, which does not involve oxidation of substrate. (1) Malic acid → Oxaloacetic acid (2) Succinic acid → Malic acid (3) Succinyl-CoA → Succinic acid (4) Isocitrate → -ketoglutaric acid 2(C51H98O6) + 145 O2 -> 102 CO2 + 98 H2O + energy The Respiratory Quotient (RQ) of a biomolecule used for respiration, as per the above equation would be : Less than 0.5 Between 1.25 and 2 1.0 Between 0.5 and 0.95 How many molecules of pyruvic acid are produced at the end of glycolysis from 206 molecules of glucose? 206 309 103 412 The number of substrate level phosphorylations in one turn of citric acid cycle is One Two Three Zero Which of the following statements is incorrect? 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 ATP is synthesized through complex V Oxidation-reduction reactions produce proton gradient in respiration During aerobic respiration, role of oxygen is limited to the terminal stage What amount of energy is released from glucose during lactic acid fermentation? More than 18% About 10% Less than 7% Approximately 15% What is the net gain of ATP when each molecule of glucose is converted to two molecules of pyruvic acid? Six Two Eight Four 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 : Both A and R are true and R is the correct explanation of A. Both A and R are true but R is NOT the correct explanation of A. A is true but R is false. A is false but R is true. Match List I with List II array ll 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 array Choose the correct answer from the options given below: (1) A-I, B-II, C-III, D-IV (2) A-II, B-I, C-IV, D-III (3) A-III, B-IV, C-I, D-II (4) A-IV, B-III, C-II, D-I The complex II of mitochondrial electron transport chain is also known as NADH dehydrogenase Cytochrome bc1 Succinate dehydrogenase Cytochrome c oxidase In the Krebs cycle, the conversion of Succinate to Fumarate is an example of which type of reaction? Dehydrogenation Decarboxylation Hydration Condensation Match List-I with List-II: array llll ; & List-I (Process) & ; & 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 array A-IV, B-II, C-I, D-III A-I, B-IV, C-III, D-II A-II, B-III, C-IV, D-I A-III, B-I, C-IV, D-II During anaerobic respiration in yeast, the products formed from glucose are: Ethanol, CO 2 , and ATP Lactic acid and ATP Water, CO 2 , and ATP Methanol and CO 2 Which step in the Citric Acid Cycle (Krebs cycle) results in the formation of GTP (or ATP ) via substrate-level phosphorylation? Conversion of Succinyl CoA to Succinic acid Conversion of Citrate to Isocitrate Conversion of Malate to Oxaloacetate Conversion of Isocitrate to -ketoglutarate The oxidative decarboxylation of Pyruvate requires the presence of which of the following co-factors? Mg 2+ and NAD + Fe 2+ and FAD Cu 2+ and ADP Zn 2+ and ATP The first 4-carbon compound formed in the Krebs Cycle by the condensation of Acetyl CoA and Oxaloacetic acid (OAA) is actually Citric acid (6C). However, which is the starting acceptor molecule? Oxaloacetic acid (OAA) Citric acid Succinic acid Malic acid During the process of respiration, -ketoglutaric acid is a key intermediate that can be used for the synthesis of which amino acid? Glutamic acid Alanine Aspartic acid Glycine The primary function of Cytokinins is to promote: Cell division Cell elongation Seed dormancy Leaf fall The 'malting process' in the brewing industry is significantly accelerated by the application of: Gibberellins Auxins Cytokinins Ethylene In tissue culture, a high ratio of Cytokinin to Auxin usually promotes the development of: Shoots Roots Callus only Secondary metabolites Which hormone delay leaf senescence, often referred to as the 'Richmond-Lang effect'? Cytokinin Auxin Abscisic Acid Ethylene Which enzyme catalyzes the final step of glycolysis, resulting in the formation of pyruvic acid? Pyruvate kinase Enolase Phosphoglyceromutase Aldolase The transition from juvenile to adult phase in plants can be accelerated by the application of: Gibberellins Auxins Abscisic Acid Cytokinins The reaction that converts Succinyl CoA to Succinic acid in the TCA cycle involves the synthesis of: GTP ATP NADPH FADH2 Which enzyme of the mitochondrial Electron Transport System (ETS) is also a part of the Citric Acid Cycle (Krebs cycle)? Succinate Dehydrogenase (Complex II) NADH Dehydrogenase (Complex I) Cytochrome c Oxidase (Complex IV) ATP Synthase (Complex V) The application of which plant growth regulator can hasten the maturity period of juvenile conifers, leading to early seed production? Gibberellins ( GA 3 ) Auxins (IAA) Cytokinins (Zeatin) Abscisic acid (ABA) Which of the following substrates produces the maximum amount of energy (ATP) per gram upon complete aerobic oxidation? Fats Proteins Carbohydrates Organic acids Which plant hormone is used to promote the growth of lateral buds by counteracting the inhibitory effect of auxin (apical dominance)? Cytokinin Gibberellin Ethylene Abscisic acid During the Citric Acid Cycle, most of the enzymes are located in the mitochondrial matrix. However, one enzyme is found in the inner mitochondrial membrane. Name it. Succinate dehydrogenase Citrate synthase Isocitrate dehydrogenase Malate dehydrogenase Besides inhibiting growth and closing stomata, Abscisic acid (ABA) plays an important role in: Seed development and maturation Seed germination Fruit ripening Stem elongation During glycolysis, the conversion of glucose to glucose-6-phosphate is catalyzed by which enzyme? Hexokinase Phosphofructokinase Aldolase Pyruvate kinase The temperature coefficient ( Q 10 ) for most biological processes, including the dark reaction of photosynthesis, is approximately: 2 1 4 10 During which stage in the complete oxidation of glucose are the greatest number of ATP molecules formed from ADP - Glycolysis Krebs cycle Electron transport chain Conversion of pyruvic acid to acetyl CoA The bioassay used to identify and measure the activity of Cytokinins is based on the: Tobacco pith culture Avena coleoptile elongation Bolting in cabbage Triple response of pea When glycerol is used as a respiratory substrate, it enters the aerobic respiratory pathway after being converted into: PGAL (Phosphoglyceraldehyde) Acetyl CoA Pyruvic acid Oxaloacetic acid What is the net energy gain (in terms of ATP) for one molecule of glucose undergoing fermentation? 2 ATP 36 ATP 38 ATP 7 ATP Seed dormancy can be caused by the presence of chemical inhibitors such as: Abscisic acid, phenolic acids, and para-ascorbic acid Gibberellic acid and Potassium nitrate Auxins and Cytokinins Ethylene and Gibberellins Which of the following hormones is responsible for root hair formation and increasing the root absorption surface? Ethylene Gibberellin ABA Cytokinin In the process of plant growth, what is the primary difference between Gibberellins and Auxins regarding cell growth? Gibberellins primarily cause internode elongation, while Auxins promote apical dominance. Auxins cause cell division, while Gibberellins only cause cell maturation. Gibberellins inhibit growth, while Auxins promote it. Auxins are gaseous, while Gibberellins are liquid. The respiratory quotient (RQ) of organic acids, such as malic acid, when oxidized in aerobic respiration, is typically: Greater than 1.0 Less than 1.0 Equal to 1.0 Zero During the 'Reduction' phase of the Calvin cycle, how many molecules of ATP and NADPH are consumed for every molecule of CO 2 fixed? 2 ATP and 2 NADPH 3 ATP and 2 NADPH 1 ATP and 1 NADPH 2 ATP and 3 NADPH The net gain of energy from the complete aerobic oxidation of one molecule of glucose is approximately 36-38 ATP. What is the estimated efficiency of this process in capturing energy from the total available energy in glucose? 34 - 40% 10 - 15% 80 - 90% Less than 5% The 'Bakane' (foolish seedling) disease of rice, which led to the discovery of Gibberellins, was caused by the fungal pathogen: Gibberella fujikuroi Ustilago nuda Puccinia graminis Albugo candida A person is undergoing prolonged fasting. His urine will be found to contain abnormal quantities of - Fats Amino acids Ketones Glucose The oxidative decarboxylation of isocitrate to -ketoglutarate in the TCA cycle produces which of the following as a byproduct? NADH + H + and CO 2 FADH 2 and CO 2 NADPH + H + and ATP GTP and O 2 Which of the following describes the 'Amphibolic' nature of the respiratory pathway? It involves both catabolic (breakdown) and anabolic (synthesis) processes It can occur both in the presence and absence of oxygen It uses both carbohydrates and proteins as substrates simultaneously It produces both CO 2 and O 2 in equal amounts For the synthesis of one molecule of glucose in the Calvin cycle of C 3 plants, how many molecules of ATP and NADPH are consumed during the reduction and regeneration phases total? 18 ATP and 12 NADPH 12 ATP and 18 NADPH 30 ATP and 12 NADPH 24 ATP and 18 NADPH In the Citric Acid Cycle, the conversion of Succinate to Fumarate is catalyzed by Succinate dehydrogenase, resulting in the production of: FADH 2 NADH + H + GTP NADPH How many ATP molecules are produced via substrate-level phosphorylation (SLP) during the complete oxidation of one molecule of glucose specifically within the Krebs Cycle? 2 ATP (or GTP) 1 ATP (or GTP) 4 ATP (or GTP) 38 ATP (or GTP) Which complex of the mitochondrial Electron Transport System contains FAD as a prosthetic group and does not pump protons into the intermembrane space? Complex II Complex I Complex III Complex IV In the 'pay-off' phase of glycolysis, the enzyme that catalyzes the first substrate-level phosphorylation to produce ATP is: Phosphoglycerate kinase Pyruvate kinase Hexokinase Aldolase For every molecule of glucose oxidized in aerobic respiration, how many molecules of CO 2 are released specifically within the mitochondrial matrix? 6 4 2 0 In the mitochondrial Electron Transport System, Ubiquinone (CoQ) acts as a mobile electron carrier between: Complex I/II and Complex III Complex III and Complex IV Complex II and Complex IV Complex I and Complex IV During glycolysis, the conversion of Glyceraldehyde-3-phosphate ( G3P ) to 1,3-bisphosphoglyceric acid ( 1,3-BPGA ) involves the reduction of: NAD + to NADH + H + NADP + to NADPH FAD to FADH 2 ATP to ADP The overall goal of glycolysis, krebs cycle and the electron transport system is the formation of ATP in one large oxidation reaction sugars nucleic acids ATP in small stepwise units. During aerobic respiration, the direction of proton flow through the F 0-F 1 ATP synthase complex to drive ATP synthesis is: From the intermembrane space to the matrix From the matrix to the intermembrane space From the stroma to the thylakoid lumen From the thylakoid lumen to the stroma What is the Respiratory Quotient (RQ) when Oxalic acid ( C 2H 2O 4 ) is used as the respiratory substrate under aerobic conditions? 4.0 1.0 0.7 Infinity The conversion of Glucose-6-phosphate to Fructose-6-phosphate in the second step of glycolysis is catalyzed by which enzyme? Phosphoglucoisomerase Hexokinase Phosphofructokinase Enolase In the mitochondrial Electron Transport System, Ubiquinone (Coenzyme Q) is located within the: Inner mitochondrial membrane Outer mitochondrial membrane Mitochondrial matrix Intermembrane space Which specific step in the Citric Acid Cycle is catalyzed by the enzyme Malate dehydrogenase? Malic acid to Oxaloacetic acid Fumaric acid to Malic acid Succinic acid to Fumaric acid Citric acid to Isocitric acid During the Citric Acid Cycle (TCA cycle), which of the following is the only 5-carbon intermediate compound produced? -ketoglutaric acid Succinic acid Isocitric acid Oxalosuccinic acid In the mitochondrial Electron Transport System, which complex is responsible for the transfer of electrons from NADH to Ubiquinone? Complex I Complex II Complex III Complex IV In the Citric Acid Cycle, the condensation of an Acetyl group with Oxaloacetic acid ( OAA ) to form Citric acid is catalyzed by which enzyme? Citrate synthase Aconitase Malate dehydrogenase Succinyl CoA synthetase During lactic acid fermentation, what is the net release of CO 2 molecules per molecule of glucose? Zero Two Four Six During the process of glycolysis, substrate-level phosphorylation occurs at how many distinct steps for one molecule of glucose? 2 steps 1 step 4 steps 3 steps Which one of the following mammalian cells is not capable of metabolising glucose to carbon-dioxide aerobically? unstraited muscle cells liver cells red blood cells white blood Which of the following describes the correct order of intermediate formation in the early stages of the Krebs Cycle? Acetyl CoA Citrate Isocitrate Citrate Acetyl CoA Isocitrate Isocitrate Citrate -ketoglutarate OAA Isocitrate Citrate The respiratory quotient (RQ) value for proteins is generally around: 0.9 1.0 0.7 More than 1.0 Ubiquinone (Coenzyme Q) receives electrons from which complex in the mitochondrial Electron Transport System? Complex I and Complex II Complex III only Complex IV only Complex I and Complex III Which enzyme of the Krebs Cycle is found attached to the inner mitochondrial membrane rather than the matrix? Succinate dehydrogenase Citrate synthase Isocitrate dehydrogenase Malate dehydrogenase How many molecules of NADH are produced during the complete oxidation of one molecule of Pyruvic acid in the mitochondria (including the link reaction and Krebs cycle)? 4 3 6 8 Which of the following is the correct order of electron carriers in the mitochondrial Electron Transport System (ETS) from Complex III to Complex IV? Cytochrome bc 1 Cytochrome c Cytochrome a-a 3 Cytochrome c Cytochrome bc 1 Cytochrome a-a 3 Ubiquinone Cytochrome b Cytochrome c 1 Cytochrome a-a 3 Cytochrome c Cytochrome bc 1 In respiration, if glycerol enters the pathway, it is first converted into: Dihydroxyacetone phosphate (DHAP) Pyruvic acid Acetyl CoA Oxaloacetic acid The enzyme responsible for the conversion of Phosphoenolpyruvate (PEP) to Oxaloacetic acid (OAA) in C 4 plants is located in the: Cytoplasm of mesophyll cells Chloroplast of bundle sheath cells Cytoplasm of bundle sheath cells Chloroplast of mesophyll cells In the process of glycolysis, the enzyme Enolase catalyzes the conversion of: 2-phosphoglycerate to Phosphoenolpyruvate 3-phosphoglycerate to 2-phosphoglycerate Phosphoenolpyruvate to Pyruvate Fructose-6-phosphate to Fructose-1,6-bisphosphate The Link Reaction (Oxidative Decarboxylation of Pyruvate) requires which of the following sets of co-factors? NAD+, CoA, TPP, Lipoate, Mg 2+ NAD+, FAD, Mn 2+ , ATP NADP+, CoA, Mg 2+ , TPP FAD, NAD+, Cu 2+ , CoA Aerobic respiratory pathway is appropriately termed :- Anabolic Catabolic Parabolic Amphibolic During glycolysis, the 6-carbon Fructose-1,6-bisphosphate is cleaved into two 3-carbon molecules by the enzyme: Aldolase Phosphofructokinase Enolase Triose phosphate isomerase During glycolysis, substrate-level phosphorylation occurs during the conversion of: 1,3-bisphosphoglyceric acid to 3-phosphoglyceric acid Glucose to Glucose-6-phosphate Fructose-6-phosphate to Fructose-1,6-bisphosphate Dihydroxyacetone phosphate to 3-phosphoglyceraldehyde How many turns of the Krebs cycle are required for the complete oxidation of one molecule of glucose? Two One Three Four The 'Glycerol-3-phosphate shuttle' is a mechanism in some plants and animals used to: Transfer electrons from cytoplasmic NADH to the mitochondrial ETS Transport glucose from the cytoplasm to the vacuole Convert fats into carbohydrates during seed germination Move oxygen into the mitochondrial matrix Which specific step of the Citric Acid Cycle (TCA cycle) is catalyzed by the enzyme Aconitase? Citrate to Isocitrate Acetyl CoA to Citrate Isocitrate to -ketoglutarate Succinate to Fumarate In glycolysis, the enzyme responsible for the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate, which also generates a molecule of ATP, is: Phosphoglycerate kinase Phosphoglycerate mutase Enolase Glyceraldehyde-3-phosphate dehydrogenase In anaerobic respiration (fermentation) in yeast, the enzyme 'Pyruvate decarboxylase' requires which of the following as a co-factor? Thiamine Pyrophosphate ( TPP ) Biotin Ascorbic acid Flavin Mononucleotide ( FMN ) Cytochrome c oxidase (Complex IV) contains two copper centers. These are known as: Cu A and Cu B Cu 1 and Cu 2 Cu and Cu Cu red and Cu ox Which of the following co-factors is NOT required by the Pyruvate Dehydrogenase complex for the Link Reaction? Biotin NAD + Coenzyme A Thiamine Pyrophosphate ( TPP ) The breakdown of fatty acids to Acetyl CoA via Beta-oxidation primarily occurs in which part of the cell in plants? Glyoxysomes and Mitochondria Lysosomes Smooth Endoplasmic Reticulum Nucleoplasm In which one of the following processes CO2 in not released ? Aerobic respiration in plants Aerobic respiration in animals Alcoholic fermentation Lactate fermentation Which of the following substances acts as a specific inhibitor of the F 0 part of the ATP synthase complex, preventing the flow of protons? Oligomycin Cyanide Rotenone Antimycin A The total number of FADH 2 molecules produced during the complete aerobic oxidation of one glucose molecule is: 2 1 10 4 In the Citric Acid Cycle, the six-carbon intermediate formed immediately after the oxidation of Isocitrate is: Oxalosuccinate -ketoglutarate Succinyl-CoA Cis-aconitate The Respiratory Quotient (RQ) of Malic acid during its complete aerobic oxidation is approximately: 1.33 1.0 0.7 0.9 Where does the Electron Transport System (ETS) occur within the mitochondria? Inner mitochondrial membrane Mitochondrial matrix Outer mitochondrial membrane Intermembrane space What is the Respiratory Quotient ( RQ ) during the anaerobic respiration of germinating seeds? Infinity 1.0 0.7 Zero In the ATP synthase complex ( F 0-F 1 ), the F 0 component is located in the: Inner mitochondrial membrane Mitochondrial matrix Intermembrane space Outer mitochondrial membrane In glycolysis, what is the net gain of ATP molecules produced via substrate-level phosphorylation from one molecule of glucose? 2 ATP 4 ATP 8 ATP 36 ATP Which of the following is the site of glycolysis in a cell? Cytoplasm Mitochondrial matrix Chloroplast Ribosomes In the mitochondrial Electron Transport System (ETS), Complex I is professionally known as: NADH dehydrogenase Succinate dehydrogenase Cytochrome bc 1 complex Cytochrome c oxidase