Biomolecules Mock Test – Class 12 Chemistry

1. Assertion: Both oxime formation and cyanohydrin formation support the existence of a carbonyl-containing form of glucose.
Reason: Hydroxylamine and hydrogen cyanide can react by addition or condensation at a carbonyl carbon.

2. For a double-stranded DNA segment containing base pairs, of which are pairs, the total number of hydrogen bonds is:

3. Use the Fischer-projection description below.
The carbonyl group is placed at the top of the vertical chain. At the stereogenic carbon farthest from the carbonyl group, the hydroxyl group lies on the right.
This monosaccharide belongs to:

4. Consider the following statements.
Statement I: Vitamin C deficiency may impair collagen-related tissue maintenance.
Statement II: Vitamin K deficiency may impair normal blood coagulation.
Statement III: Vitamin A deficiency is the principal cause of beriberi.
The acceptable statements are:

5. In a typical -helix, most amino-acid side chains:

6. Match each biomolecule in Column I with its principal association in Column II.

7. In the complete-hydrolysis equation

the required coefficient of water is:

8. A graph of optical rotation against time is recorded during acid-catalysed hydrolysis of sucrose. The curve begins at a positive value, decreases, crosses zero and approaches a negative plateau. The plateau indicates:

9. A dietary deficiency leaves several enzyme proteins present but inactive because an organic helper cannot be formed. In the same patient, a glandular messenger still reaches target cells but produces no response because the receptors are defective. The two failures most directly involve:

10. Assertion: Fructose can give positive Tollens and Fehling tests even though its open-chain form is a ketose.
Reason: In alkaline medium, fructose can rearrange through an enediol intermediate to aldose forms that reduce these reagents.

11. A carbohydrate that yields a large number of monosaccharide molecules on complete hydrolysis is a:

12. Maltose shows mutarotation in aqueous solution because:

13. A sample contains of identical mononucleotides, each containing one base, one pentose and one phosphate group. Complete cleavage into separate components produces a total of:

14. Consider the following statements about glycogen.
Statement I: It is composed of -D-glucose residues.
Statement II: Its main chains contain linkages.
Statement III: Its branch points contain linkages.
The acceptable statements are:

15. In open-chain glyceraldehyde, , the carbon atom bearing the hydroxyl group is:

16. Lactose intolerance commonly results from insufficient activity of:

17. A graph of axial DNA length in against base-pair number is a straight line through the origin with slope . One DNA segment corresponds to a graph point at . Using base pairs per turn, what is the sum of its total phosphodiester bonds and approximate helical turns?

18. Assertion: Deficiency symptoms do not justify unlimited self-administration of vitamin supplements.
Reason: Excessive intake of some vitamins, particularly fat-soluble vitamins, may lead to harmful accumulation.

19. Mild oxidation of glucose with bromine water changes:

20. Complete the deficiency relationship correctly:

21. The following results were obtained at constant enzyme concentration.

The data most strongly support the conclusion that:

22. Sample P contains nucleotides, of which are ribonucleotides and contain purines. Sample Q contains nucleotides, of which are ribonucleotides and contain purines. After mixing P and Q, determine the total moles of -hydroxyl groups and nitrogenous rings.

23. Study the data below.

The strongest inference from the data is:

24. A reaction record for two monosaccharides gives the following observations.
Sugar P forms a cyclic hemiacetal, has its anomeric carbon at , and gives sorbitol on reduction.
Sugar Q forms a cyclic hemiketal, has its anomeric carbon at , and forms the same osazone as P.
The best interpretation is:

25. Two graphs reach plateaus.
Graph P plots the specific optical rotation of a freshly prepared glucose solution against time.
Graph Q plots initial enzyme rate against substrate concentration at constant enzyme concentration.
The plateaus most appropriately represent:

26. The designation -D-glucose does not imply that the compound:

27. Many enzymes are classified chemically as:

28. The structure represents:

29. For an enzyme that requires a non-protein helper, the relation is completed by:

30. Study the hydrolysis data.

The suitable classifications of P, Q, R and S are:

31. In the hydrolysis of a peptide bond, water provides:

32. A linear double-stranded DNA molecule has an axial length of . Use per base pair and base pairs per turn. Its total hydrogen-bond count is times its total nucleotide count. The correct pair for the number of pairs and the sum of hydrogen bonds plus helical turns is:

33. The name “aldohexose” communicates that the monosaccharide:

34. The row that correctly distinguishes primary structure from an -helical secondary structure is:

35. Glucose dissolves readily in water mainly because its molecule contains:

36. Study the configurational comparison below.

The suitable matching is:

37. Six separate linear polynucleotide chains contain a combined total of nucleotide residues. They are joined end-to-end to form one continuous linear chain without loss of nucleotide residues. How many new phosphodiester bonds form, and how many phosphodiester bonds are present in the final chain?

38. Consider the following statements.
Statement I: Hydrolysability and reducing behaviour are separate carbohydrate properties.
Statement II: Every hydrolysable disaccharide is reducing before hydrolysis.
Statement III: A sweet carbohydrate may be either reducing or non-reducing.
The acceptable statements are:

39. A graph of enzyme activity against temperature rises gradually, reaches a maximum and then falls sharply. The sharp fall beyond the maximum is best attributed to:

40. Complete the structural analogy:

41. For a simple amino acid, the charge relation is completed correctly by:

42. A single linear cellulose chain contains glucose residues. Complete hydrolysis of every glycosidic linkage in this chain consumes:

43. Assertion: Addition of phosphate to a nucleoside produces a nucleotide.
Reason: A nucleoside already contains the nitrogenous base and pentose components of the nucleotide.

44. A biological molecule contains ribose, phosphate and the bases adenine, guanine, cytosine and uracil. It folds into a compact structure containing paired stems and unpaired loops and participates directly in a cellular process. The strongest conclusion is that the molecule:

45. The isoelectric point, , of an amino acid is the at which the amino acid:

46. Match each feature in Column I with its suitable description in Column II.

47. Failure of a large substrate excess to restore an enzyme’s original maximum rate is most consistent with an inhibitor that:

48. One fixed open-chain stereoisomer of glucose cyclises and creates one new stereogenic centre at . How many configurational possibilities arise solely from this newly formed centre?

49. A connected acyclic glycogen fragment is formed from glucose molecules by condensation. Its molecular formula is:

50. Read the situation below and answer the question.
A protein consists of several folded chains. A mutation does not prevent the individual chains from folding, but it removes complementary charged groups at the contact surface between two subunits. The most likely immediate consequence is: