Respiration in Plants Mock Test – Class 11 Biology

1. Four acetyl CoA molecules each complete one TCA turn. What combined output is obtained from the cycle?

2. Two sucrose molecules are hydrolysed completely, and every released monosaccharide completes glycolysis. What is the combined glycolytic output?

3. A defining feature of cellular respiration is the controlled oxidation of complex organic compounds, including the breaking of [blank] that releases considerable energy.

4. Five glucose molecules complete both ATP-investment reactions and split into ten PGAL-equivalent streams. All ten streams form BPGA and , but only six streams complete both substrate-level ATP-forming reactions and reach pyruvate. The remaining four stop before BPGA transfers phosphate to ADP. What is the resulting glycolytic record?

5. The pathway whose name literally refers to sugar splitting and whose historical alternative name is the Embden-Meyerhof-Parnas pathway is:

6. Arrange the events of alcoholic fermentation in their correct order.
P. Pyruvate decarboxylase acts on pyruvate.
Q. Acetaldehyde and are formed.
R. Alcohol dehydrogenase transfers reducing equivalents to acetaldehyde.
S. Ethanol forms while is regenerated.

7. A leaf admits oxygen through stomata, after which its cells oxidise organic molecules and form ATP. The relation between the two events is best stated as:

8. A graph follows an aerobic cell through two changes. At time , oxygen is removed. NADH rises, oxygen consumption becomes zero and mitochondrial ATP production falls, while lactate begins accumulating. At time , oxygen is restored. NADH declines, lactate accumulation slows and mitochondrial ATP production recovers. The best interpretation is:

9. Arrange the events that connect sucrose with the common glycolytic pathway.
P. Sucrose becomes available to a plant cell.
Q. Invertase hydrolyses the disaccharide.
R. Glucose and fructose are released.
S. The monosaccharides enter the glycolytic route after suitable processing.

10. Assertion: A finite standard respiratory quotient can always be calculated for alcoholic fermentation.
Reason: Alcoholic fermentation may release carbon dioxide without consuming molecular oxygen, while the standard RQ denominator is oxygen consumed.

11. A plant tissue depleted of readily available carbohydrate continues consuming oxygen and producing ATP when supplied with an organic acid. Fat and protein mobilisation are experimentally prevented. This result classifies the organic acid as:

12. Assertion: Cellular respiration is gradual and enzyme-controlled rather than a rapid uncontrolled oxidation.
Reason: ATP formed during respiration can later supply energy to cellular activities.

13. Growth and metabolic records of three microorganisms are shown below.

If oxygen is suddenly removed from actively growing cultures of all three organisms, which prediction is best supported?

14. During germination, a seed initially has an RQ near . Later, its RQ approaches , carbohydrate reserves decline and biochemical analysis shows increased deamination of amino acids. Which interpretation is most defensible?

15. During a light interval, photosynthesis in a leaf would by itself consume of carbon dioxide and release of oxygen. The intact leaf instead shows net uptake of carbon dioxide and net release of oxygen because respiration is occurring simultaneously. What respiratory gas exchange and RQ are indicated?

16. During germination, a seed's readily available carbohydrate falls while stored lipid is mobilised and oxygen consumption continues. The strongest conclusion is that:

17. Anaerobic yeast cells receive glucose and initially produce both ATP and ethanol. A drug then blocks the first committed reactions of glycolysis. Pyruvate, ethanol and ATP production all decline sharply. The strongest inference is:

18. Evaluate the following statements about the mitochondrial proton gradient.
I. Proton concentration becomes higher in the intermembrane space than in the matrix.
II. An intact inner membrane is needed to maintain this difference.
III. ATP formation requires protons to move from the matrix into the intermembrane space through .
IV. Return of protons toward the matrix can drive ATP synthesis.

19. During the first interval, a tissue oxidises carbohydrate and consumes of oxygen. During the second interval, it oxidises fat with and consumes of oxygen. What is the RQ for the two intervals combined?

20. A learner describes the EMP pathway as an anaerobic pathway separate from glycolysis. The most accurate correction is:

21. Use the mitochondrial arrangement described below. Structure P is a small mobile protein located on the intermembrane-space-facing surface of the inner membrane. It receives electrons from complex III and delivers them to complex IV. Structure P is:

22. An anaerobic culture receives an excess of glucose. Its product concentration rises steadily, but after prolonged incubation the cells show reduced growth and declining metabolic activity even though glucose remains. The most appropriate explanation is:

23. A cell is separated into cytoplasmic, mitochondrial-matrix and inner-membrane fractions. The cytoplasmic fraction forms pyruvate from glucose. The matrix fraction forms acetyl CoA and carbon dioxide when supplied with pyruvate. The inner-membrane fraction oxidises reduced coenzymes and consumes oxygen when supplied with the required carriers. The strongest conclusion is:

24. Four cellular records are obtained during glucose metabolism.

Which record most strongly supports simultaneous aerobic respiration and lactic acid fermentation within the cell population?

25. Electron-carrier measurements are made after four mitochondrial treatments.

A selective block of electron transfer through complex III is most consistent with:

26. Use the arrangement described below. Structure P is a acceptor in the mitochondrial matrix. Structure Q supplies a acetyl group attached to a carrier. Their condensation produces Structure R, a compound, and the carrier is released. P, Q and R are:

27. Three glucose molecules complete the ATP-investment phase and produce six PGAL molecules. All six PGAL molecules form BPGA and . Two triose streams stop immediately after the BPGA-to-PGA reaction, while the remaining four complete glycolysis. What is the final record?

28. Equal cultures of a microorganism receive the same substrate and temperature. Culture P is maintained without oxygen and grows actively. Culture Q receives oxygen and shows no growth, while all other conditions remain suitable. The strongest inference is that the organism:

29. A temporary shortage of develops in the mitochondrial matrix while pyruvate, coenzyme A and the link-reaction enzymes remain available. The most direct effect will be:

30. Intact mitochondria are supplied with pyruvate, oxygen, ADP and inorganic phosphate. After Treatment P, oxygen consumption remains high, the proton gradient becomes very small and ATP production falls sharply. Which change most directly explains the observations?

31. Consider the following statements about ATP-forming mechanisms in respiration.
I. Substrate-level phosphorylation involves direct phosphate transfer from a metabolic intermediate.
II. Oxidative phosphorylation depends on electron transfer, a proton gradient and ATP synthase.
III. Every substrate-level phosphorylation reaction stops immediately when oxygen is removed.
IV. Formation of GTP during conversion of succinyl CoA into succinate is substrate-level phosphorylation.

32. Consider the following statements about aerobic respiration.
I. It permits substantially more energy capture from glucose than fermentation.
II. Complete oxidation yields carbon dioxide and water.
III. Oxygen availability is essential for the full aerobic pathway.
IV. Oxygen is directly consumed during the cytoplasmic reactions of glycolysis.

33. Rates of several processes are measured in the same aerobic cell during one minute.

Which interpretation best explains why a simple sequential balance sheet may not equal the cell’s measured outcome?

34. Two tissues show the following gas exchange.

Which interpretation is best supported?

35. The approximate respiratory quotient assigned to protein respiration is:

36. Equal amounts of labelled respiratory substrate enter two growing tissues.

The difference is best explained by:

37. Match each process with its principal location in a eukaryotic cell. A Column II entry may be reused.

38. A graph plots yeast growth rate against ethanol concentration in an anaerobic glucose medium. Growth remains substantial at low concentrations, falls progressively as ethanol accumulates and approaches zero near . The pattern best explains why:

39. Both acetyl CoA molecules produced from one glucose enter the TCA cycle but are withdrawn as alpha-ketoglutarate immediately after the first oxidative decarboxylation. Which consequence applies to both interrupted turns?

40. A graph plots growth rate against increasing oxygen concentration for two microorganisms. Curve P shows substantial growth at zero oxygen and continues growing as oxygen becomes available. Curve Q shows growth only near zero oxygen and falls to no measurable growth as oxygen concentration rises. The best interpretation is:

41. Assertion: Respiratory pathways should be classified as exclusively catabolic.
Reason: Some respiratory intermediates can be withdrawn and used in the synthesis of cellular compounds.

42. Match each fat-related component with its respiratory relation. A Column II entry is used once.

43. Evaluate the following propositions about glycolysis.
I. It occurs in the cytoplasm.
II. One glucose molecule forms two molecules of pyruvic acid.
III. It completely oxidises all glucose carbon to carbon dioxide.
IV. It occurs in organisms using either aerobic or anaerobic metabolism.

44. Assertion: Complex IV receives electrons directly from ubiquinone.
Reason: Complex IV receives electrons from cytochrome c and transfers them to oxygen.

45. Equal samples of living parenchyma are maintained under identical conditions. In Sample P, natural intercellular spaces remain open. In Sample Q, the tissue is compressed so that many spaces collapse without directly killing the cells. Oxygen deficiency appears first in Q. The result indicates that:

46. A graph compares two glucose-fed cell populations. In the oxygenated population, the proportion of reduced NADH falls rapidly and ATP accumulation has a steep slope. In the oxygen-free fermenting population, NADH is recycled more slowly and ATP accumulation has a shallow slope. Which interpretation fits both curves?

47. Use the pathway arrangement described below. Stage P activates and rearranges a six-carbon hexose, Stage Q divides it into two three-carbon phosphates, and Stage R oxidises the triose stream while producing ATP. The stages are best classified as:

48. Use the tissue arrangement described below. Layer P is an external surface exposed to air. Beneath it, loosely arranged living cells surround interconnected air spaces. No living cell lies far from either Layer P or an internal air space. This arrangement chiefly supports respiration by:

49. Plant cells are supplied with a labelled carbon compound known to be an intermediate of respiration. Later, some label appears in newly synthesised amino acids while ATP formation and respiratory gas exchange continue. The strongest inference is:

50. Four glucose molecules are metabolised in the same cell population. Two undergo complete aerobic respiration, one undergoes alcoholic fermentation and one undergoes lactic acid fermentation. If total carbon dioxide evolved is divided by total oxygen consumed, the resulting value is greater than one. Why should this value not be interpreted as the RQ of a pure aerobic respiratory substrate?