NCERT NEET Biology English Medium Part-1 | Chapter 12 : Respiration in Plants.

NCERT NEET Biology English Medium Part-1 | Chapter 12 : Respiration In Plants.

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Question 1: The breaking of the C-C bonds of complex compounds through oxidation within the cells, leading to release of considerable amount of energy is called?

1. Photosynthesis.
2. Respiration.
3. Transpiration.
4. Photorespiration.

Answer: b.

Question 2: Which of the following compounds are oxidized during the process of respiration?

1. Respiratory substrates.
2. Photosynthetic substrates.
3. Inorganic solvents.
4. Structural proteins.

Answer: a.

Question 3: In plants, which of the following acts as the primary respiratory substrate?

1. Proteins.
2. Fats.
3. Carbohydrates.
4. Organic acids.

Answer: c.

Question 4: What is the main reason plants can get along without respiratory organs?

1. Each plant part takes care of its own gas exchange needs.
2. Plants do not require oxygen for respiration.
3. Plants possess lungs for gaseous exchange.
4. Plants utilize carbon dioxide exclusively.

Answer: a.

Question 5: During photosynthesis, oxygen is released within the plant cell. How does this affect respiration?

1. It stops cellular respiration.
2. It decreases the need for oxygen transport from roots.
3. It causes the plant to become an obligate anaerobe.
4. It makes oxygen availability an internal feature for leaves.

Answer: d.

Question 6: In woody plants, how does gaseous exchange occur in the thick, woody stems?

1. Through stomata.
2. Through lenticels.
3. Through root hairs.
4. Through cuticles.

Answer: b.

Question 7: The complete combustion of glucose yields which of the following as end products?

1. Carbon dioxide, water, and energy.
2. Lactic acid and energy.
3. Ethanol, carbon dioxide, and energy.
4. Carbon monoxide, water, and energy.

Answer: a.

Question 8: The strategy of the plant cell to catabolize the glucose molecule in such a way that not all the liberated energy goes out as heat is to oxidize glucose in?

1. A single explosive step.
2. Several small steps.
3. The absence of enzymes.
4. The extracellular fluid.

Answer: b.

Question 9: All living organisms retain the enzymatic machinery to partially oxidize glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is called?

1. Krebs cycle.
2. Glycolysis.
3. Electron transport system.
4. Calvin cycle.

Answer: b.

Question 10: The term glycolysis has originated from the Greek words, glycos for sugar, and lysis for?

1. Synthesis.
2. Splitting.
3. Joining.
4. Reduction.

Answer: b.

Question 11: The scheme of glycolysis was given by which group of scientists?

1. Watson, Crick, and Wilkins.
2. Gustav Embden, Otto Meyerhof, and J. Parnas.
3. Melvin Calvin and Benson.
4. Hans Krebs and Fritz Lipmann.

Answer: b.

Question 12: In anaerobic organisms, glycolysis is the only process in respiration. What is its location in the cell?

1. Mitochondria.
2. Cytoplasm.
3. Chloroplast.
4. Nucleus.

Answer: b.

Question 13: Sucrose is converted into glucose and fructose by which of the following enzymes?

1. Hexokinase.
2. Invertase.
3. Amylase.
4. Zymase.

Answer: b.

Question 14: Glucose and fructose are phosphorylated to give rise to glucose-6-phosphate by the activity of the enzyme?

1. Phosphofructokinase.
2. Hexokinase.
3. Aldolase.
4. Pyruvate kinase.

Answer: b.

Question 15: Isomerisation of glucose-6-phosphate produces which of the following intermediates in glycolysis?

1. Fructose-6-phosphate.
2. Glucose-1-phosphate.
3. Fructose-1,6-bisphosphate.
4. Phosphoglyceric acid.

Answer: a.

Question 16: How many metabolic steps are present in the glycolytic pathway to convert glucose into pyruvic acid?

1. Eight.
2. Ten.
3. Twelve.
4. Fifteen.

Answer: b.

Question 17: ATP is utilized at two steps in glycolysis. The first step is the conversion of glucose into glucose-6-phosphate. What is the second step?

1. Fructose-6-phosphate to fructose-1,6-bisphosphate.
2. Phosphoenolpyruvate to pyruvic acid.
3. 3-phosphoglyceraldehyde to 1,3-bisphosphoglycerate.
4. 2-phosphoglycerate to phosphoenolpyruvate.

Answer: a.

Question 18: Fructose-1,6-bisphosphate is split into dihydroxyacetone phosphate and?

1. 3-phosphoglyceraldehyde.
2. 2-phosphoglycerate.
3. 3-phosphoglyceric acid.
4. Phosphoenolpyruvate.

Answer: a.

Question 19: During glycolysis, one molecule of NADH + H+ is formed when which of the following is oxidized?

1. Glucose-6-phosphate.
2. Fructose-1,6-bisphosphate.
3. 3-phosphoglyceraldehyde.
4. Phosphoenolpyruvate.

Answer: c.

Question 20: The conversion of 1,3-bisphosphoglyceric acid to 3-phosphoglyceric acid is an energy yielding step. This type of ATP synthesis is called?

1. Oxidative phosphorylation.
2. Photophosphorylation.
3. Substrate level phosphorylation.
4. Reductive phosphorylation.

Answer: c.

Question 21: Which enzyme catalyzes the conversion of phosphoenolpyruvate to pyruvic acid in glycolysis?

1. Enolase.
2. Pyruvate kinase.
3. Mutase.
4. Hexokinase.

Answer: b.

Question 22: What is the net gain of ATP molecules during the glycolysis of one molecule of glucose?

1. Two.
2. Four.
3. Six.
4. Eight.

Answer: a.

Question 23: The metabolic fate of pyruvic acid depends on the cellular need. Under anaerobic conditions in yeast, what is the major pathway?

1. Lactic acid fermentation.
2. Alcoholic fermentation.
3. Aerobic respiration.
4. Photorespiration.

Answer: b.

Question 24: In alcoholic fermentation, pyruvic acid is converted to ethanol and carbon dioxide by the enzymes pyruvic acid decarboxylase and?

1. Lactic dehydrogenase.
2. Alcohol dehydrogenase.
3. Hexokinase.
4. Enolase.

Answer: b.

Question 25: During rigorous exercise, when oxygen is inadequate for cellular respiration in animal muscles, pyruvic acid is reduced to?

1. Ethanol.
2. Lactic acid.
3. Acetic acid.
4. Acetyl CoA.

Answer: b.

Question 26: The reducing agent in both lactic acid and alcoholic fermentation is?

2. FADH2.
3. NADPH.
4. NADH + H+.
5. ATP.

Answer: c.

Question 27: In both lactic acid and alcoholic fermentation, not much energy is released. Less than what percentage of the energy in glucose is released?

1. Seven percent.
2. Ten percent.
3. Fifteen percent.
4. Twenty percent.

Answer: a.

Question 28: Yeasts poison themselves to death when the concentration of alcohol reaches about?

1. Five percent.
2. Ten percent.
3. Thirteen percent.
4. Twenty percent.

Answer: c.

Question 29: For the complete oxidation of glucose and extraction of maximal energy, organisms must utilize which process?

1. Anaerobic respiration.
2. Aerobic respiration.
3. Fermentation.
4. Glycolysis alone.

Answer: b.

Question 30: Aerobic respiration leads to the complete oxidation of organic substances in the presence of oxygen, and releases?

1. Only ATP.
2. CO2, water, and a large amount of energy.
3. Lactic acid and CO2.
4. Ethanol and water.

Answer: b.

Question 31: Pyruvate, which is formed by the glycolytic catabolism of carbohydrates in the cytosol, enters which organelle for further aerobic respiration?

1. Nucleus.
2. Chloroplast.
3. Mitochondrial matrix.
4. Endoplasmic reticulum.

Answer: c.

Question 32: The crucial events in aerobic respiration include the stepwise removal of all hydrogen atoms, leaving how many molecules of CO2?

1. Two.
2. Three.
3. Four.
4. Six.

Answer: b.

Question 33: The synthesis of ATP via the passing on of electrons to molecular oxygen occurs on the?

1. Outer mitochondrial membrane.
2. Inner mitochondrial membrane.
3. Mitochondrial matrix.
4. Cytoplasm.

Answer: b.

Question 34: Pyruvic acid undergoes oxidative decarboxylation in the mitochondrial matrix to produce?

1. Citric acid.
2. Acetyl CoA.
3. Oxaloacetic acid.
4. Succinyl CoA.

Answer: b.

Question 35: The reaction catalyzed by pyruvate dehydrogenase requires the participation of several coenzymes, including NAD+ and?

1. FAD.
2. Coenzyme A.
3. ATP.
4. Cytochrome c.

Answer: b.

Question 36: During the oxidative decarboxylation of two molecules of pyruvic acid, how many molecules of NADH are produced?

1. One.
2. Two.
3. Three.
4. Four.

Answer: b.

Question 37: Acetyl CoA enters a cyclic pathway known as the tricarboxylic acid cycle, more commonly called?

1. Calvin cycle.
2. Glyoxylate cycle.
3. Krebs cycle.
4. Cori cycle.

Answer: c.

Question 38: The first step of the TCA cycle is the condensation of acetyl group with oxaloacetic acid (OAA) and water to yield?

1. Isocitric acid.
2. Citric acid.
3. Alpha-ketoglutaric acid.
4. Succinic acid.

Answer: b.

Question 39: The enzyme that catalyzes the condensation of acetyl CoA and OAA to form citric acid is?

1. Citrate synthase.
2. Aconitase.
3. Isocitrate dehydrogenase.
4. Malate dehydrogenase.

Answer: a.

Question 40: Citrate is isomerised to isocitrate. This is followed by two successive steps of decarboxylation, leading to the formation of?

1. Malic acid and oxaloacetic acid.
2. Alpha-ketoglutaric acid and succinyl-CoA.
3. Fumaric acid and malic acid.
4. Succinic acid and fumaric acid.

Answer: b.

Question 41: During the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesized. This is an example of?

1. Oxidative phosphorylation.
2. Substrate level phosphorylation.
3. Photophosphorylation.
4. Reductive amination.

Answer: b.

Question 42: In a coupled reaction during the TCA cycle, GTP is converted to GDP with the simultaneous synthesis of?

1. AMP from ADP.
2. ATP from ADP.
3. CTP from CDP.
4. UTP from UDP.

Answer: b.

Question 43: In one turn of the TCA cycle, how many points are there where NAD+ is reduced to NADH + H+?

1. One.
2. Two.
3. Three.
4. Four.

Answer: c.

Question 44: In the TCA cycle, FAD is reduced to FADH2 at how many specific points?

1. One.
2. Two.
3. Three.
4. Four.

Answer: a.

Question 45: The continued oxidation of acetyl CoA via the TCA cycle requires the continuous replenishment of which compound?

1. Pyruvic acid.
2. Oxaloacetic acid.
3. Citric acid.
4. Malic acid.

Answer: b.

Question 46: What is the primary role of the electron transport system (ETS) in the mitochondria?

1. To synthesize glucose from carbon dioxide.
2. To oxidize NADH and FADH2 and pass electrons to oxygen.
3. To produce carbon dioxide from pyruvate.
4. To transport ATP out of the mitochondria.

Answer: b.

Question 47: Electrons from NADH produced in the mitochondrial matrix are oxidized by which complex of the ETS?

1. Complex II.
2. Complex I.
3. Complex III.
4. Complex IV.

Answer: b.

Question 48: The electrons from Complex I are transferred to which mobile electron carrier located within the inner membrane?

1. Cytochrome c.
2. Ubiquinone.
3. Plastocyanin.
4. Plastoquinone.

Answer: b.

Question 49: Ubiquinone also receives reducing equivalents via FADH2, which is associated with which complex?

1. Complex I.
2. Complex II.
3. Complex III.
4. Complex IV.

Answer: b.

Question 50: The reduced ubiquinone (ubiquinol) is oxidized with the transfer of electrons to cytochrome c via which complex?

1. Complex I.
2. Complex II.
3. Cytochrome bc1 complex (Complex III).
4. Cytochrome c oxidase (Complex IV).

Answer: c.

Question 51: Cytochrome c is a small protein attached to the outer surface of the inner membrane and acts as a mobile carrier for transfer of electrons between?

1. Complex I and II.
2. Complex II and III.
3. Complex III and IV.
4. Complex I and III.

Answer: c.

Question 52: Complex IV of the ETS is also known as cytochrome c oxidase. It contains cytochromes a and a3, and two centers of which metal?

1. Iron.
2. Copper.
3. Zinc.
4. Magnesium.

Answer: b.

Question 53: As electrons pass from one carrier to another via complex I to IV in the ETS, they are coupled to ATP synthase for the production of ATP. Which complex is ATP synthase?

1. Complex II.
2. Complex III.
3. Complex IV.
4. Complex V.

Answer: d.

Question 54: The oxidation of one molecule of NADH gives rise to how many molecules of ATP through the ETS?

1. One.
2. Two.
3. Three.
4. Four.

Answer: c.

Question 55: The oxidation of one molecule of FADH2 through the electron transport system produces how many molecules of ATP?

1. One.
2. Two.
3. Three.
4. Four.

Answer: b.

Question 56: The role of oxygen in aerobic respiration is crucial because it acts as the final acceptor of?

1. Carbon.
2. Hydrogen.
3. ATP.
4. Water.

Answer: b.

Question 57: In respiration, the energy of oxidation-reduction is utilized for the production of proton gradient required for phosphorylation. This process is called?

1. Photophosphorylation.
2. Substrate level phosphorylation.
3. Oxidative phosphorylation.
4. Reductive phosphorylation.

Answer: c.

Question 58: According to the chemiosmotic hypothesis, what drives the synthesis of ATP by ATP synthase?

1. A gradient of sodium ions.
2. The movement of electrons.
3. A proton gradient across the inner membrane.
4. The breakdown of water.

Answer: c.

Question 59: Complex V (ATP synthase) consists of two major components, F1 and F0. What is the role of the F1 headpiece?

1. It acts as a proton channel.
2. It is the site for synthesis of ATP from ADP and Pi.
3. It binds oxygen.
4. It transports electrons.

Answer: b.

Question 60: The F0 component of ATP synthase is an integral membrane protein complex that forms the channel through which?

1. Electrons cross the membrane.
2. Protons cross the inner membrane.
3. ATP exits the mitochondria.
4. Water enters the matrix.

Answer: b.

Question 61: For each ATP produced, how many protons pass through F0 from the intermembrane space to the matrix down the electrochemical proton gradient?

1. One.
2. Two.
3. Three.
4. Four.

Answer: b.

Question 62: To calculate the net gain of ATP for every glucose molecule oxidized, it is assumed that the NADH synthesized in glycolysis is transferred into the mitochondria and undergoes?

1. Reduction.
2. Fermentation.
3. Oxidative phosphorylation.
4. Substrate level phosphorylation.

Answer: c.

Question 63: In reality, the respiratory pathway is not a strictly linear sequence because intermediates are?

1. Never utilized for other pathways.
2. Withdrawn to synthesize other compounds as needed.
3. Destroyed immediately after formation.
4. Locked within the mitochondria permanently.

Answer: b.

Question 64: A net gain of how many ATP molecules is theoretically possible during aerobic respiration of one molecule of glucose?

1. 2 ATP.
2. 18 ATP.
3. 38 ATP.
4. 48 ATP.

Answer: c.

Question 65: How does the energy yield of fermentation compare to that of aerobic respiration?

1. Fermentation yields more energy.
2. They yield the same amount of energy.
3. Fermentation accounts for only a partial breakdown of glucose, yielding less energy.
4. Fermentation yields twice as much energy.

Answer: c.

Question 66: NADH is oxidized to NAD+ rather slowly in fermentation. How is this oxidation in aerobic respiration?

1. Very slow.
2. Extremely slow.
3. Non-existent.
4. Very vigorous.

Answer: d.

Question 67: Respiratory pathways are primarily catabolic, but since they also provide intermediates for biosynthesis, they are better considered as?

1. Anabolic pathways.
2. Amphibolic pathways.
3. Endergonic pathways.
4. Non-metabolic pathways.

Answer: b.

Question 68: If fats are to be respired, they must first be broken down into?

1. Glycerol and fatty acids.
2. Amino acids.
3. Glucose and fructose.
4. Pyruvate and lactate.

Answer: a.

Question 69: Before entering the respiratory pathway, fatty acids are degraded into which compound?

1. Pyruvic acid.
2. Acetyl CoA.
3. Alpha-ketoglutaric acid.
4. Phosphoglyceraldehyde.

Answer: b.

Question 70: Glycerol would enter the respiratory pathway after being converted to?

1. Phosphoglyceraldehyde (PGAL).
2. Phosphoenolpyruvate.
3. Citric acid.
4. Lactic acid.

Answer: a.

Question 71: Proteins are degraded by proteases into amino acids, which enter the respiratory pathway after undergoing?

1. Phosphorylation.
2. Deamination.
3. Decarboxylation.
4. Polymerization.

Answer: b.

Question 72: An amino acid after deamination may enter the TCA cycle as pyruvic acid, acetyl CoA, or?

1. Another stage within the Krebs cycle.
2. Cytochrome c.
3. Glucose-6-phosphate.
4. Fructose-1,6-bisphosphate.

Answer: a.

Question 73: The ratio of the volume of CO2 evolved to the volume of O2 consumed in respiration is called the?

1. Respiratory rate.
2. Respiratory Quotient (RQ).
3. Photosynthetic quotient.
4. Metabolic ratio.

Answer: b.

Question 74: The Respiratory Quotient (RQ) depends heavily upon the?

1. Temperature of the environment.
2. Type of respiratory substrate used.
3. Amount of water available.
4. Light intensity.

Answer: b.

Question 75: When carbohydrates are used as substrate and are completely oxidized, what is the RQ value?

1. 0.7.
2. 0.9.
3. 1.0.
4. More than 1.

Answer: c.

Question 76: When fats are used in respiration, the RQ is?

1. Less than 1.
2. Equal to 1.
3. More than 1.
4. Infinity.

Answer: a.

Question 77: The calculated RQ for tripalmitin, a fatty acid, is approximately?

1. 1.0.
2. 0.9.
3. 0.7.
4. 1.3.

Answer: c.

Question 78: When proteins are the respiratory substrates, the RQ would be about?

1. 0.7.
2. 0.9.
3. 1.0.
4. 1.5.

Answer: b.

Question 79: In living organisms, are respiratory substrates strictly one type of molecule at a time?

1. Yes, only carbohydrates are ever used.
2. Yes, only fats are used.
3. No, rarely is a single type of substrate used; often a mixture is utilized.
4. Pure proteins are used exclusively in plants.

Answer: c.

Question 80: Which statement about pure proteins or fats as respiratory substrates is correct?

1. They are never used as respiratory substrates under normal conditions.
2. They enter the pathway without modification.
3. They yield more CO2 than O2 consumed.
4. They have an RQ greater than 1.

Answer: a.

Question 81: Which intermediate of the TCA cycle is used for the synthesis of chlorophyll, cytochromes, and phytochrome?

1. Citric acid.
2. Succinyl CoA.
3. Oxaloacetic acid.
4. Alpha-ketoglutaric acid.

Answer: b.

Question 82: Which of the following is an intermediate of glycolysis that can be used for the synthesis of glycerol?

1. Phosphoenolpyruvate.
2. 3-phosphoglyceraldehyde.
3. Dihydroxyacetone phosphate.
4. Pyruvic acid.

Answer: c.

Question 83: To withdraw oxaloacetic acid for the synthesis of pyrimidines and alkaloids, the Krebs cycle is considered an?

1. Amphibolic pathway.
2. Anabolic pathway exclusively.
3. Anaerobic pathway.
4. Irreversible pathway.

Answer: a.

Question 84: The inner mitochondrial membrane has invaginations called cristae, which serve to?

1. Increase surface area for ETS complexes.
2. Store genetic material.
3. Synthesize glucose.
4. Trap light energy.

Answer: a.

Question 85: Cyanide is a potent poison that halts respiration by inhibiting which complex of the electron transport system?

1. Complex I.
2. Complex II.
3. Complex III.
4. Complex IV (cytochrome c oxidase).

Answer: d.

Question 86: What is the main difference between substrate-level phosphorylation and oxidative phosphorylation?

1. Substrate-level needs oxygen, oxidative does not.
2. Substrate-level uses a proton gradient, oxidative uses enzyme substrates directly.
3. Substrate-level directly transfers a phosphate from a substrate to ADP, oxidative uses an electrochemical gradient.
4. Oxidative phosphorylation occurs in the cytoplasm, substrate-level in mitochondria.

Answer: c.

Question 87: During the complete oxidation of a glucose molecule, how many molecules of water are formed as a metabolic byproduct?

2. 2.
3. 4.
4. 6.
5. 12.

Answer: c.

Question 88: In the conversion of pyruvic acid to acetyl CoA, which specific gas is released?

1. Oxygen.
2. Nitrogen.
3. Carbon dioxide.
4. Carbon monoxide.

Answer: c.

Question 89: Which step is commonly known as the connecting link between glycolysis and the Krebs cycle?

1. Conversion of PEP to Pyruvate.
2. Conversion of Pyruvate to Acetyl CoA.
3. Conversion of Acetyl CoA to Citrate.
4. Conversion of Citrate to Isocitrate.

Answer: b.

Question 90: How many turns of the Krebs cycle are required for the complete oxidation of one molecule of glucose?

1. One.
2. Two.
3. Three.
4. Four.

Answer: b.

Question 91: Identify the correct sequence of electron carriers in the cytochrome bc1 complex.

1. Cytochrome b -> Fe-S -> Cytochrome c1.
2. Cytochrome c1 -> Fe-S -> Cytochrome b.
3. Fe-S -> Cytochrome b -> Cytochrome c1.
4. Cytochrome b -> Cytochrome c1 -> Fe-S.

Answer: a.

Question 92: Which of the following is NOT a characteristic feature of fermentation?

1. Incomplete oxidation of glucose.
2. Net gain of only 2 ATP molecules.
3. Slow oxidation of NADH to NAD+.
4. Requires the presence of a functional electron transport chain.

Answer: d.

Question 93: If the RQ value is less than 1, it implies that?

1. More carbon dioxide is evolved than oxygen consumed.
2. More oxygen is consumed than carbon dioxide evolved.
3. The substrate is a carbohydrate.
4. Respiration is anaerobic.

Answer: b.

Question 94: Malic acid is a 4-carbon compound. How many decarboxylation steps occur between citric acid and malic acid in the TCA cycle?

1. None.
2. One.
3. Two.
4. Three.

Answer: c.

Question 95: Which of the following enzymes of the TCA cycle is located in the inner mitochondrial membrane rather than the matrix?

1. Citrate synthase.
2. Alpha-ketoglutarate dehydrogenase.
3. Succinate dehydrogenase.
4. Malate dehydrogenase.

Answer: c.

Question 96: During rigorous exercise, the accumulation of which compound in the muscle cells causes fatigue?

1. Pyruvic acid.
2. Lactic acid.
3. Carbon dioxide.
4. Ethanol.

Answer: b.

Question 97: Fructose-1,6-bisphosphate aldolase splits a 6-carbon sugar into two 3-carbon sugars. This enzyme belongs to which class of enzymes?

1. Oxidoreductases.
2. Transferases.
3. Lyases.
4. Ligases.

Answer: c.

Question 98: Oxygen acts as the final hydrogen acceptor. Its role is restricted to which stage of respiration?

1. The terminal stage.
2. The initial stage of glycolysis.
3. The Krebs cycle.
4. The Link reaction.

Answer: a.

Question 99: If a mutant plant cell lacks Complex III, which of the following processes will immediately stop?

1. Glycolysis.
2. Formation of acetyl CoA.
3. Flow of electrons from ubiquinol to cytochrome c.
4. Conversion of PEP to pyruvate.

Answer: c.

Question 100: Which of the following statements best describes the term 'respiratory balance sheet'?

1. A calculation of oxygen inhaled versus exhaled.
2. A theoretical calculation of net ATP yield based on sequential assumptions.
3. An exact measurement of ATP in a living cell.
4. A record of water loss during transpiration.

Answer: b.

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