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

1. The membrane of a thylakoid is ruptured, while the chloroplast envelope remains intact. The earliest expected result is:

2. Mitochondria are commonly called the powerhouses of the cell because they:

3. A graph plots relative protein-synthesis activity on the horizontal axis and average nucleolar size on the vertical axis. Across comparable cells, nucleolar size rises as protein-synthesis activity increases. The most justified interpretation is:

4. In , George Palade reported small dense particles associated with the cytoplasm and endoplasmic reticulum in electron micrographs. These particles were later identified as:

5. Two bacterial samples give the following results.

The observations support the conclusion that:

6. Chloroplast counts are recorded in two cell samples.

The records are best interpreted as:

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

The record that requires correction is:

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

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

9. Near one end of a chromosome lies a primary constriction. A tiny arm extends beyond the constriction, while a much longer arm extends in the opposite direction. The chromosome is:

10. A mutation prevents centrioles from organising basal bodies and also prevents their normal contribution to spindle formation in an animal cell. Which paired outcome is most directly expected?

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

12. From outside inward, the envelope of a bacterium consists of P, Q and R. P may be loose or capsular, Q is rigid, and R directly surrounds the cytoplasm. Movement of a test solute into the cytoplasm is regulated mainly at:

13. Assertion: A centromere and a kinetochore should not be treated as two names for the same chromosome structure.
Reason: The centromere is the primary constriction, whereas disc-shaped kinetochores occur on its sides.

14. 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.

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

16. Assertion: Blocking vesicle release from the Golgi trans face can cause processed secretory products to accumulate within the Golgi apparatus.
Reason: The trans face is the principal site at which ER-derived vesicles first enter the Golgi stack.

17. An unknown ribosome is isolated from inside a membrane-bound organelle of a eukaryotic cell. It belongs to the class. The organelle could most reasonably be:

18. Engulfment of food particles is experimentally blocked in Amoeba, but the contractile vacuole continues its regular filling and emptying cycle. The most likely observation is:

19. An external bacterial appendage has three labelled regions. P is a long projecting strand, Q is a short curved connector at its base, and R is embedded in the cell envelope. The correct identification is:

20. The outer coating of a bacterium is loose and not organised into a thick, tough covering. It is described as a ______ rather than a capsule.

21. Four chromosomes are described below.

Which identification is correct?

22. Equal cytoplasmic volumes from three cell types are examined.

The strongest conclusion supported by the records is:

23. A Gram-positive population and a Gram-negative population both survive well in a dilute medium while their cell walls remain intact. Enzymatic wall removal greatly increases bursting in both populations, although their Gram responses remain different. The best conclusion is:

24. 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:

25. Which comparison between a basal body and a typical axoneme is correct?

26. An unknown cell contains a plasma membrane, cytoplasm, ribosomes and DNA concentrated in a region not surrounded by a nuclear envelope. Endoplasmic reticulum and Golgi apparatus are absent. It is best classified as:

27. Three cells are compared below.

The most accurate interpretation of cell Q is:

28. Equal cells are supplied with two substances. Substance P is a neutral solute moving from higher to lower concentration through the lipid bilayer. Substance Q is an ion being accumulated where its concentration is already higher. After ATP synthesis is inhibited, P continues to enter while Q accumulation stops. The strongest inference is:

29. Two bacterial membrane extensions are compared.

Which conclusion best explains the different effects?

30. Radioactive amino acids are supplied to isolated chloroplasts with intact stroma ribosomes but damaged cytoplasmic ribosomes outside the organelles. A small set of labelled proteins still appears inside the chloroplasts. The strongest inference is:

31. A student concludes that the nucleus is unnecessary for all living eukaryotic cells after observing mature mammalian erythrocytes and sieve-tube elements. Which correction is most appropriate?

32. The records below concern mature cells.

Which set contains all the biologically consistent records?

33. Match each bacterial surface component in Column I with its description in Column II. A Column II entry is used once.

34. Membrane proteins are marked at one small region of a living cell. Over time, the marks spread laterally across the membrane surface, but the proteins do not enter the cytoplasm or extracellular fluid. This observation most directly supports:

35. A motile appendage is covered by plasma membrane and contains a microtubular axoneme. It must be:

36. A typical plant cell is treated with enzymes that remove its wall. Its plasma membrane, nucleus, mitochondria and large vacuole remain intact, but the particular tissue examined contains no developed chloroplasts. Which conclusion is most justified?

37. Match each entry in Column I with its most appropriate relation in Column II. A Column II entry is used once.

38. Consider the following statements about cellular structures.
I. Mitochondria are membrane-bound organelles.
II. Lysosomes and vacuoles are membrane-bound structures.
III. Ribosomes are enclosed by a membrane.
IV. The animal-cell centrosome is non-membranous.

39. In most green plants, the cells expected to contain abundant chloroplasts are located mainly in the:

40. A polar solute is initially more concentrated outside a cell. During phase P, it enters through a carrier while ATP synthesis is blocked. During phase Q, an ATP-dependent pump returns the solute outside even after its external concentration becomes higher. The transport sequence is:

41. Match each prokaryotic structure in Column I with its most appropriate relation in Column II. A Column II entry is used once.

42. An unknown eukaryotic cell lacks a cell wall and plastids but contains a centrosome with two perpendicular centrioles near the nucleus. The most reasonable classification is:

43. Assertion: Cytoplasm is present in both prokaryotic and eukaryotic cells.
Reason: Only eukaryotic cytoplasm supports biochemical reactions required for the living state.

44. Assertion: A chromosome satellite should be counted as a separate complete chromosome.
Reason: A satellite is a small chromosome segment separated from the main region by a secondary constriction.

45. Starting in the stroma outside a thylakoid, passing directly through the thylakoid and returning to stroma on the opposite side gives the sequence:

46. Consider the following statements about ribosomes.
I. They contain ribosomal RNA and proteins.
II. They lack a surrounding membrane.
III. They participate directly in polypeptide synthesis.
IV. Their internal material is enclosed by a single lipid bilayer.

47. Ribosomes attached to rough endoplasmic reticulum are experimentally detached, but free cytoplasmic ribosomes and ribosomes inside mitochondria remain undisturbed. The immediate distributional change is that:

48. A graph plots radioactive label intensity against time for four locations after a short pulse labels a newly synthesised secretory protein. The RER curve peaks first, the cis-Golgi curve peaks next, the trans-Golgi curve peaks later, and the extracellular-medium curve rises last. The trend most strongly supports:

49. Equal samples of intact cells are gently separated into a cytoplasmic fraction and a fraction containing mainly empty boundary material. Numerous soluble reaction activities are detected in the cytoplasmic fraction, while the boundary fraction shows far fewer. The strongest supported inference is that:

50. Consider the following statements about the Golgi apparatus.
I. It commonly occurs near the nucleus.
II. It consists of parallel stacks of flattened cisternae.
III. Its cis face is convex and receiving, while its trans face is concave and releasing.
IV. Its two faces are structurally identical and completely disconnected.