Biomolecules Mock Test – Class 11 Biology

1. Which statements correctly describe the identification of compounds from living tissue?
I. Components of an extract are separated before a particular compound is isolated.
II. An isolated sample may still require purification.
III. Analytical techniques can provide a molecular formula and evidence for probable structure.
IV. A molecular formula alone always reveals the complete arrangement of atoms in a compound.

2. Tests performed on an acid-insoluble fraction give the following observations.
P. Long chains joined by peptide bonds are detected.
Q. Long sugar chains are detected.
R. Polynucleotide chains are detected.
S. Low-mass lipids remain associated with membrane fragments.
Which conclusion is strongest?

3. A fresh cell preparation initially contains water by mass. Some water evaporates, while the masses of proteins, carbohydrates, lipids, nucleic acids and ions remain unchanged. Which immediate percentage change is expected?

4. Analyse the fractionation records below.

Which pair best demonstrates that the same fraction can contain substances for different structural reasons?

5. A monomeric protein retains most of its local -helices and -sheets after treatment, but these elements no longer pack into the original compact shape. Its biological activity falls sharply. The level most directly disrupted is:

6. Assess the following statements about molecular-mass guides.
I. A compound of may fit the broad micromolecule description even though it exceeds the usual acid-soluble range.
II. A compound of lies within both approximate descriptions.
III. A compound of lies between the common micromolecule and biomacromolecule guides.
IV. Every substance must be acid-insoluble regardless of its structure and extraction conditions.

7. Consider the following statements about ligases.
I. They catalyse joining of two compounds.
II. They may form carbon–oxygen, carbon–sulphur, carbon–nitrogen or phosphorus–oxygen bonds.
III. Their defining action is cleavage of peptide bonds using water.
IV. They are distinguished from isomerases because they create a bond between separate reactants.

8. Four polysaccharide samples are tested under identical conditions.

Which synthesis is best supported?

9. Match each cellulose-containing material with the relation that applies most directly. A Column II entry is used once.

10. Two groups of growing animals receive otherwise identical purified diets. Group P receives all essential amino acids. Group Q receives the same diet except that one essential amino acid is absent. Growth is reduced in Q, and adding the missing amino acid restores normal growth. What is the strongest inference?

11. The protein component of a cofactor-dependent enzyme, when considered without its required non-protein component, is called the ______.

12. Let represent wet mass, dry mass, ash mass, water mass and combustible matter. Which set of relations correctly represents the drying-and-combustion analysis?

13. A learner counts only the hydrocarbon -group and reports that palmitic acid has carbons and arachidonic acid has carbons. What correction is required?

14. Living systems are built from atoms and molecules that are not living by themselves. Which statement best explains how these components contribute to life?

15. Three amino acids have the common framework . In Structure P, ; in Structure Q, ; and in Structure R, . Identify P, Q and R.

16. Equal amounts of one enzyme are placed in four tubes containing progressively higher substrate concentrations. Product formation per minute is , , and units, respectively. What is the strongest inference from the last two tubes?

17. Two purified triglycerides contain the same glycerol backbone and the same number of esterified fatty acids. Lipid P contains no bonds and melts at a higher temperature than Lipid Q, whose fatty acids contain several bonds. Which conclusion is best supported?

18. Arrange the events in a simple metabolic pathway in their logical order.
P. The initial substrate binds to the enzyme catalysing the first step.
Q. An intermediate is formed and released.
R. The intermediate becomes the substrate for a later enzyme.
S. A later product is formed.

19. An extract contains glucose, an amino acid, water, and phosphate ions. Which classification best represents these substances?

20. Let represent amino acids, monosaccharides, nucleotides, proteins, polysaccharides, nucleic acids and ordinary membrane lipids. Which symbolic description is correct?

21. Assertion: Organic composition alone cannot distinguish a prosthetic group from a coenzyme.
Reason: Both are organic cofactors, but prosthetic groups are tightly bound whereas coenzymes associate transiently.

22. Consider the following statements about physical and chemical changes.
I. A physical change can alter shape or state without rearranging chemical bonds.
II. A chemical reaction involves breaking existing bonds and forming new ones.
III. Every change in physical state produces a new chemical substance.
IV. Hydrolysis of a polymer into its monomers is a chemical change.

23. Consider the following statements about phosphorus in biological samples.
I. Phosphorus may occur in nucleotide phosphate groups.
II. Phosphorus may occur in membrane phospholipids.
III. Phosphorus may contribute to inorganic residue detected in ash.
IV. Detection of phosphorus alone is sufficient to identify an unknown substance as a nucleic-acid polymer.

24. A polypeptide has the sequence from its N-terminal end to its C-terminal end. An enzyme removes only the N-terminal alanine without cleaving any other bond. What are the new terminal residues?

25. In the pathway , the active site of recognises B but not A. What is the most direct significance of this specificity?

26. A cell preparation has a total mass of . Water forms and proteins form of this mass. By how much does the water mass exceed the protein mass?

27. Evaluate the following statements about molecular-mass descriptions used for small cellular compounds.
I. Acid-soluble compounds commonly fall around .
II. A broader description commonly treats compounds of as micromolecules.
III. The two descriptions serve related but different contexts and are not exact contradictory laws.
IV. Every compound of must enter the acid-soluble fraction under all extraction conditions.

28. A plant reserve polysaccharide releases only glucose on complete hydrolysis and initially gives a blue colour with iodine. A treatment disrupts its helical organisation without breaking the glucose chain into monomers. After treatment, the blue response disappears. What is the strongest conclusion?

29. Assertion: A diglyceride containing two fatty-acid residues is not necessarily an unsaturated lipid.
Reason: The terms diglyceride and unsaturated describe different structural features: number of fatty acids esterified to glycerol and presence of bonds, respectively.

30. A mutant enzyme binds substrate normally and converts it into product, but product release from the active site is extremely slow. Which immediate pattern is most likely?

31. A cell has normal receptor proteins and responds to an external signal, but it lacks functional GLUT-4 molecules. Which defect is most directly expected?

32. A lipid isolated from neural tissue does not match the component descriptions of a simple fatty acid, a glyceride or lecithin. No further structural evidence is available. What is the strongest justified conclusion?

33. A substrate-response graph has . The velocity reaches at a substrate concentration of . According to the stated graph relation, what is ?

34. Yeast cells producing ethanol under fermentative conditions are shifted to the stated aerobic context while glucose remains available. Which immediate pathway-level prediction is most appropriate?

35. A pathway contains the reactions shown below.



Which classification of , and is correct?

36. Two forms of the same enzyme are tested at identical temperature, enzyme concentration and substrate concentration. The normal enzyme reaches maximum activity at pH , whereas a variant reaches maximum activity at pH . Both show lower activity on either side of their respective peaks. What is the strongest interpretation?

37. A substitution changes one amino acid in a haemoglobin -subunit. The altered subunit still folds into its usual individual shape but fails to associate correctly with the other haemoglobin subunits. Which conclusion best fits the evidence?

38. Examine the metabolite records below.

Which classification best fits the complete evidence?

39. A diet supplies abundant starch and lipids but lacks one amino acid that the body cannot synthesise adequately. Protein synthesis becomes limited even though energy-rich nutrients are plentiful. Which explanation is most appropriate?

40. A fresh tissue sample has a wet mass of , a dry mass of and an ash mass of . Which set correctly gives the masses of water, combustible organic material and inorganic residue?

41. The structural observations for one protein are listed below.

Which record identifies secondary structure?

42. Elemental analysis of a tissue sample and a rock sample detects carbon, hydrogen, oxygen, nitrogen, sulphur and several mineral elements in both. Their percentages differ markedly. What is the strongest inference?

43. Evaluate the following statements about nucleotides and nucleic acids.
I. DNA and RNA consist of nucleotide building units.
II. Nucleosides lacking phosphate are the complete repeating units of nucleic acids.
III. Nucleic acids are associated with genetic-material roles.
IV. A nucleotide contains a nitrogenous base, sugar and phosphate.

44. Match each compound with its most appropriate chemical category. Column II entries may be reused.

45. Formation of a new bond joins two separate compounds into one product. The responsible enzyme belongs to the:

46. Four acid-insoluble substances are characterised below.

Which substance is a nucleic acid?

47. Equal enzyme and substrate concentrations are placed in two tubes. Tube P receives no additional chemical, while Tube Q receives Chemical X. Product formation in Q falls sharply. After X is removed, the enzyme from Q regains its original activity. Which conclusion is strongest?

48. Assertion: Cellulose is classified as a homopolymeric polysaccharide.
Reason: Its long chains are formed by repetition of glucose as one monosaccharide type.

49. Equal amounts of succinic dehydrogenase are placed in three tubes. Tube P contains succinate, Tube Q contains succinate plus malonate, and Tube R contains a much higher succinate concentration plus the same malonate concentration as Q. Product formation is highest in P, lowest in Q and partly restored in R. What does the experiment show?

50. Arrange the events that restore activity to a cofactor-dependent apoenzyme.
P. The inactive protein component is present as an apoenzyme.
Q. Its specific non-protein cofactor becomes available.
R. The cofactor associates appropriately with the apoenzyme.
S. Catalytic activity is restored.