Biomolecules Mock Test – Class 11 Biology

1. A learner assumes that every visually exposed tip in a branched glycogen drawing must be a reducing end. The supplied labels instead identify a right reducing end and left non-reducing ends. What correction is required?

2. 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?

3. In a horizontal representation, the leftmost residue of a polypeptide is explicitly identified as the first amino acid and the rightmost residue as the last. How should the two ends be labelled?

4. Arrange the following events in the order that produces a polypeptide from separate amino acids.
P. Individual amino acids are available.
Q. Adjacent amino-acid residues become linked by peptide bonds.
R. The linked chain lengthens through additional amino-acid residues.
S. A linear polypeptide with a definite residue order is obtained.

5. A graph plots liquid fraction on the vertical axis against temperature on the horizontal axis for two glycerides. Curve P changes from mostly solid to mostly liquid near , while Curve Q makes the same transition near . At , which interpretation is supported?

6. An investigator records only the presence or absence of elements in living tissue and nearby soil. The two lists are almost the same. What change would most directly reveal the major chemical distinction emphasised by such a comparison?

7. Examine the records for four substances recovered from an acid-insoluble fraction.

Which synthesis is most accurate?

8. Arrange the products in order of increasing number of fatty acids esterified to glycerol.
P. Triglyceride
Q. Monoglyceride
R. Diglyceride

9. Four polysaccharide samples are tested under identical conditions.

Which synthesis is best supported?

10. Consider the following statements about the ends of a represented polypeptide.
I. The first residue defines the N-terminal end.
II. The last residue defines the C-terminal end.
III. Removing the first residue can expose a new N-terminal residue without changing the last residue.
IV. Adding a residue specifically at the C-terminal end necessarily changes the N-terminal residue.

11. A branched glucose polymer is drawn with its labelled non-reducing end on the left and its labelled reducing end on the right. Numerous side branches arise from the main chain. Which description fits the arrangement?

12. Three polysaccharides are analysed as follows.

Which identification is appropriate?

13. Match each organic class with the relation that applies most directly. A Column II entry is used once.

14. Two molecules both contain an amino group, a carboxyl group and hydrogen attached to the same -carbon. One has , while the other has . Their relationship is best described as:

15. Four purified enzymes catalyse the reactions shown below, with water participating directly in every cleavage.

Which classification is supported by the common reaction mechanism?

16. A chemical binds to an enzyme and decreases or shuts off its catalytic activity without serving as the normal substrate. The chemical is classified as:

17. Substance P dissolves in water and is recovered unchanged after the water evaporates. Substance Q is broken into chemically different smaller molecules during treatment. How should the two changes be classified?

18. Classify the changes shown below.

Which classification is correct?

19. A structural polysaccharide is isolated independently from a plant cell wall, plant-pulp paper and cotton fibre. Each sample yields glucose units on complete breakdown. Which identification best integrates the evidence?

20. An investigator analyses only the acid-soluble filtrate and concludes that the measured amino acids, sugars and ions represent every major chemical class in the original tissue. What is the main limitation of this conclusion?

21. A purified enzyme is active before treatment. After its required metal ion is removed, the protein remains intact but activity becomes undetectable. Re-addition of the same metal restores activity, whereas addition of an unrelated metal does not. Which conclusion is best supported?

22. An unknown enzyme converts a compound into a product having the same molecular formula but a different three-dimensional arrangement. A second unknown enzyme converts two separate molecules into one covalently connected product. Which ordered classification is supported?

23. A three-carbon molecule is arranged as . Which structural feature makes it suitable for forming a triglyceride?

24. The amino-acid composition of an enzyme is preserved, but the order of its residues is extensively rearranged. What outcome is most likely?

25. Assertion: Glutamic acid is classified as an acidic amino acid.
Reason: It contains more amino groups than carboxyl groups.

26. A pathogenic bacterium depends on succinic dehydrogenase for an important metabolic step. Chemical M resembles succinate, decreases enzyme activity and slows bacterial growth. When the succinate concentration is greatly increased, enzyme activity is partly restored despite the continued presence of M. Which conclusion is best supported?

27. A pathway proceeds as . A treatment selectively inactivates , while and remain functional. Which initial result is most likely?

28. Three analytical records are obtained from living tissue.

How should the records be classified?

29. A change is classified as chemical rather than merely physical when it involves ______.

30. Malonate competitively inhibits succinic dehydrogenase mainly because malonate:

31. A DNA-type pyrimidine nucleotide is divided into three samples.

Which conclusion is most appropriate?

32. Analyse the fractionation records below.

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

33. A glucose storage polymer isolated from animal tissue loses most of its branch points after an experimental treatment, while its glucose units remain chemically unchanged. Which conclusion is most appropriate?

34. Assertion: A molecule containing cytosine, ribose and phosphate is an RNA-type pyrimidine nucleotide.
Reason: Cytosine is a pyrimidine, ribose gives RNA-type identity and phosphate completes nucleotide composition.

35. Two versions of an enzyme are tested with the same substrate. The normal enzyme forms an enzyme-substrate complex and produces product. A mutant enzyme has a changed active-site shape, forms almost no enzyme-substrate complex and produces almost no product. What is the strongest inference?

36. Four molecular records are shown below.

Which records are correctly classified?

37. A mutant isomerase still binds its substrate, but conversion to the positional isomer falls sharply. The substrate and product have the same molecular formula. Which conclusion is strongest?

38. Four carbohydrate polymers have the compositions shown below.

Which polymer is most directly identified as cellulose?

39. A tissue has a wet mass of , a dry mass of and an ash mass of . What are the water percentage of wet mass and the combustible organic percentage of dry mass, respectively?

40. A functional enzyme consists of two folded polypeptide subunits. The subunits are separated under conditions that preserve each chain's secondary and tertiary structures. Neither isolated subunit is active, but activity returns when the two are mixed and reassociate. What is the strongest inference?

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

42. Haem is selectively removed from purified catalase without breaking the polypeptide chain. Catalytic activity disappears, and activity returns after haem is reattached. What does this result demonstrate?

43. Cooling an enzyme solution to makes its activity very low. When the same solution is returned to its favourable temperature, activity returns almost completely. What does this result indicate?

44. Two cell preparations have the compositions shown below.

Which comparison is supported?

45. 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?

46. An activation-energy graph has a substrate level of , an uncatalysed peak of and a catalysed peak of . A separate substrate-response graph for the enzyme has , and velocity is at substrate. Which pair of values is correct?

47. A pathway contains the following substrate specificities.

The normal is replaced by an enzyme that recognises X but cannot bind Y. Which outcome is most likely?

48. Review the records below.

Which record requires correction?

49. A reaction transfers hydrogen-related reducing equivalents from one substrate to another. One substrate becomes oxidised and the other becomes reduced. Why is the enzyme classified as an oxidoreductase rather than an ordinary transferase?

50. Equal amounts of starch and cellulose are placed in separate tubes and treated with the same iodine solution. The starch tube becomes blue, while the cellulose tube does not. What is the strongest structural inference?