Which of the following statements regarding protein functional diversity (NCERT Table 9.5) are correct?
Statement I: RuBisCO is the most abundant protein in the entire biosphere. Statement II: GLUT-4 enables glucose transport into cells. Statement III: Antibodies fight infectious agents in living organisms. Statement IV: Insulin is a digestive enzyme, while trypsin is a hormone.
Statement IV is incorrect because trypsin is an enzyme, whereas insulin is a hormone. Statements I, II, and III faithfully summarize NCERT Table 9.5.
Question 62 of 100
📘 CLASS XI
Which of the following statements regarding polysaccharide structures and chain directionality are correct?
Statement I: Cellulose is a homopolymer composed of glucose monosaccharides. Statement II: Starch serves as a storehouse of energy in plants, while animals store energy as glycogen. Statement III: In a glycogen chain, the right end is non-reducing and the left end is reducing. Statement IV: Inulin is a polymeric polysaccharide composed of fructose monomers.
Statement III is incorrect because in glycogen the right end is reducing and the left end is non-reducing. Statements I, II, and IV are correct.
Question 63 of 100
📘 CLASS XI
Which of the following statements regarding helical polysaccharides and iodine binding are correct?
Statement I: Starch forms helical secondary structures that trap I₂ molecules to produce a blue colour. Statement II: Cellulose does not contain complex helices and cannot hold I₂. Statement III: Cotton fiber and paper made from plant pulp are cellulosic in nature. Statement IV: Fungal cell walls are composed of helical starch that turns dark red with iodine.
Statement IV is incorrect because fungal cell walls contain chitin, not helical starch. Statements I, II, and III correctly describe starch, cellulose, and cellulosic materials.
Question 64 of 100
📘 CLASS XI
Which of the following statements regarding chitin and amino-sugar polymers are correct?
Statement I: The exoskeleton of arthropods contains a complex polysaccharide named chitin. Statement II: Building blocks of chitin include amino-sugars like glucosamine and N-acetyl galactosamine. Statement III: Complex polysaccharides like chitin are mostly homopolymers. Statement IV: Chitin is a heteropolymer composed of alternating glucose and fructose units.
Statement IV is incorrect because chitin is described as a homopolymer composed of amino-sugar monomers, not alternating glucose and fructose units. Statements I, II, and III correctly reflect NCERT.
Question 65 of 100
📘 CLASS XI
Which of the following statements regarding the four organizational levels of protein structure are correct?
Statement I: Primary structure provides positional information and amino acid sequence of a protein. Statement II: In primary structure representation, the N-terminal amino acid is on the left end and the C-terminal is on the right end. Statement III: In proteins, only right-handed helices are observed in secondary structure. Statement IV: Tertiary folding into a hollow woolen ball is non-essential for biological activity.
Statement IV is incorrect because tertiary structure is absolutely necessary for the biological activities of proteins. Statements I, II, and III correctly describe primary sequence directionality and helix chirality.
Question 66 of 100
📘 CLASS XI
Which of the following statements regarding quaternary protein architecture and haemoglobin subunits are correct?
Statement I: Quaternary structure describes the architectural arrangement of multiple polypeptide subunits relative to each other. Statement II: Adult human haemoglobin consists of 4 subunits: two α-type and two β-type subunits. Statement III: Individual subunits of haemoglobin are fused into a single rigid linear rod without quaternary architecture. Statement IV: Quaternary subunit arrangements can resemble linear strings of spheres or cubes.
Statement III is incorrect because adult human haemoglobin is an assembly of four distinct subunits (2α and 2β) exhibiting classic quaternary structure. Statements I, II, and IV correctly describe quaternary architecture.
Question 67 of 100
📘 CLASS XI
Which of the following statements regarding ribozymes, active sites, and thermal stability are correct?
Statement I: Almost all enzymes are proteins, but catalytic nucleic acids called ribozymes also exist. Statement II: An active site is a crevice or pocket formed by the folding of tertiary protein structure. Statement III: Inorganic catalysts work efficiently at high temperatures and high pressures. Statement IV: Thermophilic organisms possess fragile enzymes that denature completely above 30°C.
Statement IV is incorrect because thermophilic organisms possess thermally stable enzymes that retain catalytic activity up to 80°–90°C. Statements I, II, and III accurately describe ribozymes, active sites, and catalyst properties.
Question 68 of 100
📘 CLASS XI
Which of the following statements regarding reaction rate formulas and carbonic anhydrase speed are correct?
Statement I: Rate of a chemical process is expressed as δP/δt. Statement II: Reaction rates double or decrease by half for every 10°C change in temperature. Statement III: Uncatalysed formation of carbonic acid from CO₂ and H₂O forms about 200 molecules per hour. Statement IV: Carbonic anhydrase accelerates the reaction to form 600,000 molecules per hour.
Statement IV is incorrect because carbonic anhydrase catalyses the formation of about 600,000 molecules every second, not per hour. Statements I, II, and III correctly summarize reaction kinetics.
Question 69 of 100
📘 CLASS XI
Which of the following statements regarding glycolytic metabolic pathways in different organisms are correct?
Statement I: Conversion of glucose to pyruvic acid involves ten enzyme-catalyzed metabolic steps. Statement II: In human skeletal muscle under anaerobic conditions, lactic acid is formed. Statement III: In yeast during fermentation under anaerobic conditions, ethanol (alcohol) is produced. Statement IV: Aerobic respiration in skeletal muscle produces ethanol as the primary end product.
Statement IV is incorrect because ethanol is produced during anaerobic fermentation in yeast, not during aerobic respiration in skeletal muscle. Statements I, II, and III correctly describe glycolytic outcomes.
Question 70 of 100
📘 CLASS XI
Which of the following statements regarding enzyme-substrate complex formation and activation energy are correct?
Statement I: Substrate (S) binding to the active site forms a transient enzyme-substrate (ES) complex. Statement II: During substrate binding, the substrate is transformed into a high-energy transition state structure. Statement III: Activation energy is the difference in average energy content of S from that of the transition state. Statement IV: Enzymes increase the activation energy barrier to slow down metabolic side reactions.
Statement IV is incorrect because enzymes lower the activation energy barrier, thereby accelerating chemical reactions. Statements I, II, and III correctly explain ES complex formation and activation energy.
