Respiration in Plants Mock Test – Class 11 Biology

1. Equal quantities of the same organic substrate release energy units when fully oxidised in two experimental systems.

Which conclusion is most appropriate?

2. The stomata of all leaves and the lenticels of all woody stems are sealed with an impermeable material, while root surfaces remain exposed to aerated soil. The earliest direct effect is expected to be:

3. A growing tissue sharply increases fatty-acid synthesis from acetyl CoA, while the total rate of acetyl CoA formation remains unchanged. The most likely immediate respiratory consequence is:

4. Use the arrangement described below. A sugar enters a pathway located in the cytoplasm. After a series of enzyme-controlled reactions, two compounds are produced, and no mitochondrion is required for this conversion. The pathway is:

5. A mitochondrial preparation oxidises NADH molecules and FADH molecules completely. Using the assignments of per NADH and per FADH, the predicted ATP yield is:

6. Arrange the events linking cytoplasmic glycolysis to entry of carbon into the TCA cycle.
P. Glycolysis forms pyruvate.
Q. Pyruvate enters the mitochondrial matrix.
R. Pyruvate undergoes oxidative decarboxylation.
S. Acetyl CoA becomes available to combine with oxaloacetate.

7. 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:

8. Preparation P is a soluble extract supplied with PEP and ADP; it forms ATP without a membrane or oxygen. Preparation Q is an inner-membrane vesicle supplied with ADP and inorganic phosphate; it forms ATP only when a proton gradient is imposed. Which classification is correct?

9. Gas exchange is recorded for four aerobic samples.

Which sample is most consistent with complete oxidation of carbohydrate?

10. Metabolite levels are measured after four different treatments.

A block in the isomerisation of glucose-6-phosphate to fructose-6-phosphate is most consistent with:

11. Carbon flow from pyruvate is compared in two anaerobic pathways.

The most accurate inference is:

12. 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:

13. Use the pathway arrangement described below. Region P contains glucose, PGAL and pyruvate. An arrow carries pyruvate into Region Q, where acetyl CoA, citrate and oxaloacetate occur. Reduced carriers formed in Q transfer electrons to complexes in Boundary R, where oxygen is reduced and ATP synthase operates. Which interpretation is correct?

14. A variegated plant has green leaves, a non-green stem region and actively growing roots. The roots continue to respire in darkness. The most direct source of their respiratory organic substrate is:

15. An anaerobic bacterial culture continues receiving glucose. Lactate concentration rises, the medium becomes increasingly acidic and growth slows. When acidity is partly neutralised without removing glucose or lactate, growth temporarily improves. The strongest inference is:

16. 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.

17. Four NADH molecules and four FADH molecules each donate one electron pair completely to the respiratory chain. Using the stated ATP assignments and terminal oxygen relation, what are the total ATP yield and oxygen consumption?

18. Cellular respiration is most accurately described as:

19. Carbohydrate supply is compared in three plant tissues.

The combined record best supports which conclusion?

20. Mitochondrial extracts are supplied with succinyl CoA, GDP and inorganic phosphate. Extract P contains the active enzyme system for conversion to succinate; Extract Q lacks that activity. Only P forms succinate and GTP. The result supports the conclusion that:

21. Three tissues have the same respiratory demand but differ in their distance from an external or internal air space.

The data support which relation?

22. During one interval, total oxygen consumption by a tissue is . Carbohydrate accounts for of this oxygen use. The remaining oxygen consumption is divided equally between protein and fat. Using RQ values of , and , respectively, what is the overall RQ?

23. Illuminated cyanobacterial cells are supplied with labelled carbon dioxide. Label first appears in carbohydrate and later, after transfer to darkness, appears in respiratory carbon dioxide while ATP-dependent activities continue. The observations most strongly support the conclusion that:

24. Assertion: Organic food respired by non-green root cells ultimately originates from photosynthesis.
Reason: Root cells manufacture all their respiratory carbohydrates directly from inorganic carbon in darkness.

25. Four cellular records are obtained during glucose metabolism.

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

26. Four glucose molecules undergo normal cleavage in glycolysis. How many triose phosphate molecules are initially produced, and how many triose streams subsequently enter the common PGAL pathway after DHAP conversion?

27. Mitochondrial measurements are made before and after oxygen removal.

The pattern most strongly indicates that oxygen:

28. Cleavage of fructose-1,6-bisphosphate continues normally, but conversion of DHAP into PGAL is completely blocked. Per glucose molecule, the immediate effect on the triose-level pathway will be:

29. Electron transport establishes movement of toward the intermembrane space. A membrane defect allows of these protons to return without passing through ATP synthase. Using the relation through per ATP, how many ATP molecules can be formed from the remaining proton flow?

30. Use the cellular arrangement described below. Region P surrounds the mitochondrion and contains the enzymes that form pyruvate from glucose. Region Q is enclosed by the inner mitochondrial membrane and contains enzymes that release carbon dioxide from pyruvate and acetyl groups. Region R is the folded membrane carrying respiratory complexes and ATP synthase. Which flow correctly connects the three regions?

31. Consider the following statements about conversion of succinyl CoA into succinate.
I. The reaction produces GTP by substrate-level phosphorylation.
II. GTP can support formation of ATP from ADP.
III. ATP production at this stage requires electron flow to oxygen.
IV. The reaction occurs after the two TCA decarboxylations.

32. A disrupted-cell preparation is separated into a cytoplasmic fraction and a mitochondrial fraction. Each receives glucose, necessary cofactors and suitable enzymes. Pyruvate accumulates only in the cytoplasmic fraction. The result most directly supports the conclusion that:

33. Assertion: GTP formation during the TCA cycle may continue briefly after oxygen is removed.
Reason: The succinyl CoA-to-succinate step is substrate-level phosphorylation and does not use oxygen directly, although sustained cycle turnover later depends on regeneration of oxidised coenzymes.

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

35. Arrange the events that allow a stored fat to contribute carbon to respiration.
P. The fat is split into glycerol and fatty acids.
Q. Glycerol and fatty acids undergo different preparatory conversions.
R. Glycerol-derived carbon enters near PGAL, while fatty-acid-derived carbon enters as acetyl CoA.
S. Both routes become connected with the central respiratory pathway.

36. Five glucose molecules undergo anaerobic metabolism. Three follow alcoholic fermentation, while two follow lactic acid fermentation. Which combined record is correct?

37. A pathway map shows a stored fat dividing into Component P and Component Q. P is converted into an intermediate that enters near PGAL, while Q supplies acetyl CoA for the TCA cycle. P and Q are, respectively:

38. Five glucose molecules complete the conversion of BPGA into PGA. If each occurrence of this reaction forms one ATP, how many ATP molecules are produced at this step?

39. A graph plots oxaloacetate concentration against time in an isolated mitochondrial preparation receiving acetyl CoA continuously. Curve P falls briefly after each acetyl addition but returns near its starting level before the next addition. Curve Q falls after each addition and never recovers. The best interpretation is:

40. Assertion: Doubling the amount of glucose undergoing complete aerobic oxidation doubles both oxygen consumption and carbon-dioxide evolution without changing the respiratory quotient.
Reason: Respiratory quotient depends on the ratio of carbon-dioxide volume evolved to oxygen volume consumed, rather than on the absolute amount of substrate oxidised.

41. Assertion: Conversion of pyruvate into acetyl CoA is a substrate-level phosphorylation reaction.
Reason: During this conversion, one carbon is released as and is reduced to .

42. A mutation prevents complex IV from transferring electrons to oxygen but leaves oxygen concentration and all upstream carriers initially normal. What change is expected as respiration continues?

43. Two intact tissues both show . Tissue P is supplied only with purified protein, whereas Tissue Q contains carbohydrate and fat reserves. Which conclusion is justified?

44. Three glucose molecules undergo complete aerobic oxidation. Before oxidative phosphorylation is counted, what totals are produced for carbon dioxide, reduced coenzymes and direct ATP equivalents?

45. Equal amounts of glucose undergo anaerobic metabolism in yeast and oxygen-limited muscle. Which comparison is correct?

46. Identical mitochondria are supplied with NADH, oxygen, ADP and inorganic phosphate. Preparation P has an intact inner membrane, while Preparation Q has a disrupted inner membrane but functioning electron carriers. Both oxidise some NADH, yet substantial ATP forms only in P. The strongest inference is:

47. A reaction mixture containing PGAL, and inorganic phosphate is allowed to complete the PGAL-oxidation step.

The expected record is:

48. For the relation to give a finite substrate-related value, the gas volumes should arise from [blank].

49. Match each respiratory stage or combination with its standard output. A Column II entry is used once.

50. Arrange the events by which stored carbohydrate can support cellular respiration.
P. A storage carbohydrate is mobilised.
Q. Glucose or another usable sugar becomes available.
R. The sugar enters the glycolytic pathway.
S. Pyruvate is formed and can undergo further metabolism.