Cell: The Unit of Life Mock Test – Class 11 Biology

1. Assertion: A polysome consists of several different messenger RNA molecules, each carrying only one ribosome.
Reason: Several ribosomes can attach to one messenger RNA and translate the same message simultaneously.

2. A viable cell has DNA, cytoplasm, ribosomes and a plasma membrane but lacks both a nuclear envelope and a cell wall. Its organisation is most consistent with:

3. Cell P has a rigid wall outside its plasma membrane, several plastids and a vacuole occupying most of the central region. Cell Q has no wall or plastids but contains a centriole pair near its nucleus. The most accurate interpretation is:

4. A graph plots relative activity of an isolated lysosomal hydrolase on the vertical axis against pH on the horizontal axis. Activity is highest in the acidic region, declines near neutral pH and remains low in the alkaline region. The graph supports the conclusion that:

5. Two chloroplast fractions are analysed.

P and Q are most accurately identified as:

6. The functional records of four organelles are shown below.

The group whose recorded activities represent coordinated components of the endomembrane system is:

7. Consider the following statements about microbodies.
I. They are minute membrane-bound vesicles.
II. They contain various enzymes.
III. They occur in both plant and animal cells.
IV. They are non-membranous reserve granules comparable to bacterial glycogen inclusions.

8. A figure has two panels. In Panel P, the outermost boundary is a thin plasma membrane. In Panel Q, a rigid layer lies outside a thin plasma membrane. The most accurate interpretation is:

9. A membrane surrounding a nucleus bears ribosomes on its cytoplasmic surface and is continuous with a ribosome-bearing endoplasmic-reticulum cisterna. The membrane is most likely the:

10. A mutant cell shows a sharp decline in aerobic ATP production. Its mitochondrial inner membrane has very few cristae, but chlorophyll-containing thylakoids, Golgi secretion and cytoplasmic translation remain normal. The most strongly supported defect is:

11. Two flagella are compared.

P and Q are respectively:

12. Assertion: Schleiden's conclusion connected the diversity of plant cells with the cellular organisation of plant tissues.
Reason: Repeated observations of many plants supported a generalisation that plant bodies are composed of cells.

13. The same cell is examined with two instruments. A light microscope reveals its overall outline and nucleus, while an electron microscope resolves much finer internal membranes. The best inference from these observations is that:

14. The transport records below refer to an intact plasma membrane.

The record that requires correction is:

15. Evaluate the following statements about ribosome distribution.
I. Ribosomes occur in prokaryotic and eukaryotic cells.
II. Ribosomes may lie freely in the cytoplasm.
III. Ribosomes may occur on rough endoplasmic reticulum in eukaryotic cells.
IV. Ribosomes are restricted to the membrane-bound nucleus.

16. During identification of typical plant and animal cells, which pair of structures would be least useful for distinguishing the two because both commonly possess them?

17. Animal cells are treated with a substance that prevents centrioles from contributing to spindle organisation but leaves chromosomal DNA replication and mitochondrial ATP production intact. The most direct expected defect is:

18. Assertion: The presence of a flagellum does not by itself establish whether a cell is prokaryotic or eukaryotic.
Reason: Prokaryotic and eukaryotic cells may both possess flagella, but their flagella differ fundamentally in structure.

19. A cell diagram shows two short cylindrical structures near the nucleus. Cylinder P is viewed longitudinally, while cylinder Q is viewed in cross-section. Their long axes are perpendicular, and both lie within a diffuse surrounding region. The complete structure is:

20. Match each feature in Column I with the organelle relation in Column II. A Column II entry is used once.

21. Arrange the following events in the pathway of a newly synthesised secretory protein.
P. Translation on a ribosome attached to rough ER
Q. Entry into an ER-derived transport vesicle
R. Arrival at the Golgi cis face
S. Modification and movement toward the Golgi trans face
T. Delivery in a vesicle to the plasma membrane

22. Oxygen concentration is initially higher outside a cell than inside it. Oxygen enters through the lipid region of the membrane until the difference is greatly reduced, even when cellular ATP production is temporarily blocked. The process is:

23. A drug detaches all but one ribosome from each bacterial messenger RNA without degrading the messenger RNA or inhibiting the remaining ribosome. Which change is most likely?

24. A treatment blocks nuclear pores without rupturing the nuclear envelope. RNA export from the nucleus and import of selected cytoplasmic proteins both decline, while mitochondrial ATP production and existing cytoplasmic ribosomes remain initially functional. The most direct diagnosis is:

25. Which statement remains fully within the supported biological description of DNA in a typical human somatic cell?

26. Near the nucleus of a typical animal cell, two short non-membranous cylinders lie approximately at right angles within amorphous surrounding material. Together, this region is the:

27. A treatment selectively destroys chlorophyll-containing thylakoid membranes while leaving most stroma enzymes initially active. Which immediate pattern is most likely?

28. A substance enters bacterial cells and selectively disables their ribosomes without immediately damaging DNA, the plasma membrane or stored inclusions. The earliest direct effect should be:

29. Evaluate the following statements about endoplasmic-reticulum organisation.
I. It forms a network of tubules and cisternae.
II. Its membranes enclose a luminal compartment.
III. It separates luminal space from surrounding cytoplasm.
IV. Its lumen is continuous with the extracellular environment through permanent open pores.

30. An isolated membrane is subjected first to a gentle surface treatment and then to a membrane-disrupting treatment. Protein P is released during the gentle step, while protein Q is released only after disruption of the lipid bilayer. The most justified classification is:

31. A cell retains all of its major components, but coordination among them is disrupted. Several isolated reactions continue briefly, yet the system can no longer regulate or maintain itself. This condition indicates that:

32. Four particles isolated from a bacterial cytoplasm are described below.

The record that matches a typical prokaryotic ribosome is:

33. Assertion: Lysosomes and vacuoles are both included in the endomembrane system.
Reason: Lysosomal hydrolytic enzymes generally function optimally at acidic pH.

34. A cell fraction contains particles made of RNA and proteins. The particles synthesize polypeptides when supplied with messenger RNA, amino acids and suitable cellular factors, but no lipid membrane can be detected around them. They are:

35. A mutant centriole contains nine peripheral units, but each unit has only two microtubules instead of three. Which conclusion is most accurate?

36. Identical cells are maintained under two conditions. Cells in P receive sufficient oxygen, while cells in Q experience severe oxygen limitation. Their mitochondria remain structurally present in both conditions. The most likely immediate difference is:

37. An isolated mitochondrion can carry out some biochemical reactions for a limited period but cannot maintain independent living existence. This observation best supports the conclusion that:

38. Which term names the centriole-like structure from which a eukaryotic cilium or flagellum emerges?

39. Starting in the cytoplasm and moving directly into the nucleoplasm across an intact region of nuclear envelope that is not a pore, which sequence is correct?

40. A treatment selectively disrupts one of the three protein filament systems of a eukaryotic cell, while the other two filament systems and all membrane-bound organelles remain intact. The most justified conclusion is:

41. Consider the following statements about secondary constrictions and satellites.
I. A secondary constriction is distinct from the primary centromere.
II. It may occur at a constant location on a chromosome.
III. It may separate a small chromosome segment called a satellite.
IV. The satellite is an independent whole chromosome with its own centromere.

42. Examine the following cellular records.

The record requiring correction is:

43. A newly synthesised secretory protein is labelled inside a living cell. The label appears first in rough endoplasmic reticulum, later in Golgi cisternae and finally in vesicles near the plasma membrane. Little label enters mitochondria. The observation most strongly supports:

44. Consider the following statements about a duplicated chromosome.
I. Its primary constriction is called the centromere.
II. Disc-shaped kinetochores occur on the sides of the centromere.
III. The centromere holds the two chromatids together.
IV. Every secondary constriction is another centromere.

45. Consider the following statements about the walls of plant and fungal cells.
I. The wall lies outside the plasma membrane.
II. It is a rigid, non-living component.
III. It contributes to shape and protection from mechanical damage and infection.
IV. It may participate in cell interaction and restrict undesirable macromolecules.

46. Match each ribosomal feature in Column I with its description in Column II. A Column II entry is used once.

47. Which chronological sequence is correct?

48. A mutation prevents coordinated beating of numerous short surface projections but leaves one long locomotory projection in another cell type unaffected. The function most directly reduced in the first cell type is:

49. Measurements of one chloroplast are in length and in width. Which interpretation is correct?

50. Assertion: A complete cell is regarded as the smallest organisation capable of independent living existence.
Reason: Essential living activities depend on coordinated interactions among the cell boundary, cytoplasmic machinery and internal components.