Consider the following statements regarding gaseous exchange in plants:
I. Plants possess specialized respiratory organs similar to animals for gas exchange. II. Each plant part takes care of its own gas-exchange needs with very little transport between parts. III. Distance for gas diffusion in large plants is short because living cells are located close to the surface. IV. Loose packing of parenchyma cells provides an interconnected network of air spaces.
Which of the statements given above are correct?
Statement I is incorrect because plants lack specialized respiratory organs and rely on stomata and lenticels. Statements II, III and IV are correct because each part exchanges gases independently, diffusion distances are short, and parenchyma cells provide interconnected air spaces.
Question 2 of 100
📘 CLASS XI
Read the following statements about cellular respiration and respiratory substrates:
I. Breaking of C-C bonds of complex organic compounds through oxidation yields energy. II. Proteins, fats, and organic acids can serve as respiratory substrates under certain conditions. III. Glucose oxidation releases all trapped chemical energy in a single explosive step. IV. Energy released during respiration is directly used by cells without ATP synthesis.
Which of the statements given above are incorrect?
Statement III is incorrect because glucose is oxidized in a series of enzyme-catalyzed steps. Statement IV is incorrect because energy is first conserved in ATP before being utilized. Statements I and II are correct.
Question 3 of 100
📘 CLASS XI
Consider the following statements about living cells in woody stems and roots:
I. In thick woody stems, living cells are present in thin layers beneath and inside the bark. II. Interior cells of thick woody stems are dead and provide mechanical support only. III. Lenticels are absent in woody stems. IV. Almost all living plant cells have at least part of their surface in contact with air.
Which of the above statements are correct?
Statement III is incorrect because woody stems possess lenticels for gaseous exchange. Statements I, II and IV correctly describe the arrangement of living tissues and aeration.
Question 4 of 100
📘 CLASS XI
Read the following statements regarding energy transformation in respiration:
I. Photosynthesis converts light energy into chemical energy stored in bonds of carbohydrates. II. Breakdown of complex molecules to release energy occurs in cytoplasm and mitochondria in eukaryotes. III. Non-green plant organs do not require food oxidation since they do not photosynthesize. IV. ATP serves as the universal energy currency of the cell.
Which of the above statements are correct?
Statement III is incorrect because non-green plant organs depend on oxidation of translocated food for energy. Statements I, II and IV are correct.
Question 5 of 100
📘 CLASS XI
Regarding plant respiration during photosynthesis:
I. Availability of O₂ is not a problem in photosynthesizing cells because O₂ is released within the cell. II. Leaves respire at rates significantly higher than animal tissues. III. Large volumes of gases are exchanged mainly during photosynthesis. IV. Roots and stems have much higher gas exchange demands than leaves during daytime.
Which of the above statements are correct?
Statements I and III are correct. Statements II and IV are incorrect because plant respiration rates are much lower than those of animals and gas exchange demand is generally low except during photosynthesis.
Question 6 of 100
📘 CLASS XI
Consider the following statements regarding respiratory substrates:
I. Glucose is the most favored substrate for cellular respiration. II. Pure proteins or fats are regularly used as primary substrates in living organisms. III. Organic acids can be used as respiratory substrates under specific conditions in some plants. IV. Starch and sucrose are converted to monosaccharides before entering glycolytic pathways.
Which of the above statements are correct?
Statement II is incorrect because proteins and fats are not normally used as the sole respiratory substrates. Statements I, III and IV are correct.
Question 7 of 100
📘 CLASS XI
Read the following statements regarding cellular compartmentalization of respiration:
I. Glycolysis takes place exclusively in the cytoplasm of all living organisms. II. Complete oxidation of pyruvate occurs inside the chloroplast in eukaryotes. III. TCA cycle enzymes are located in the mitochondrial matrix. IV. Electron transport chain is located on the outer mitochondrial membrane.
Which of the statements given above are correct?
Statement II is incorrect because pyruvate oxidation occurs in mitochondria. Statement IV is incorrect because the electron transport chain is located on the inner mitochondrial membrane. Statements I and III are correct.
Question 8 of 100
📘 CLASS XI
Which of the following statements about plant gas exchange adaptations are true?
I. Translocation of gases across long distances in plants occurs via active vascular transport. II. Stomata are specialized structures primarily responsible for leaf gas exchange. III. Parenchyma loose packing creates interconnected air spaces facilitating diffusion. IV. Roots receive oxygen exclusively transported from leaves through phloem.
Which option contains only correct statements?
Statements II and III are correct. Statements I and IV are incorrect because there is very little gas transport between plant parts; each organ manages its own gas exchange.
Question 9 of 100
📘 CLASS XI
Consider the following statements regarding the evolutionary perspective of respiration:
I. First cells on Earth evolved in an atmosphere devoid of molecular oxygen. II. All living organisms lack enzymatic machinery for anaerobic glucose oxidation. III. Facultative anaerobes can survive in both aerobic and anaerobic conditions. IV. Obligate anaerobes require oxygen for their metabolic processes.
Which of the above statements are correct?
Statement II is incorrect because all living organisms retain glycolytic machinery to partially oxidize glucose anaerobically. Statement IV is incorrect because obligate anaerobes require oxygen-free conditions. Statements I and III are correct.
Question 10 of 100
📘 CLASS XI
Read the following statements about ATP synthesis during respiration:
I. Energy liberated during C-C bond breakdown is directly released as free heat in one step. II. Stepwise release of energy allows coupling with ATP synthesis. III. Energy stored in ATP is utilized in various endergonic life processes. IV. Carbon skeletons generated during respiration are wasted as excretory products.
Which of the above statements are correct?
Statement I is incorrect because oxidation occurs in slow, stepwise enzymatic reactions. Statement IV is incorrect because carbon skeletons serve as precursors for biosynthesis. Statements II and III are correct.
