Sexual Reproduction in Flowering Plants Mock Test – Class 12 Biology

1. Use the interaction described below. Event P occurs when a Yucca-associated moth transfers pollen to the receptive floral surface. Event Q occurs when the same moth deposits eggs in relation to the ovary. Which interpretation best relates the two events?

2. A reproductive event in one embryo sac produces both a diploid zygote and a triploid primary endosperm nucleus after delivery of two male gametes. Which conclusion is most appropriate?

3. Seed-viability records are summarised below.

Which conclusion is justified by these records alone?

4. Complete the relation correctly: an ovule is attached to the placenta by the ______, while the point where this stalk joins the ovule body is the ______.

5. Which statement most accurately describes the relation between nucellar embryony and polyembryony?

6. Ovary P contains a single ovule, whereas Ovary Q contains many ovules. All ovules in both ovaries are successfully fertilised and each develops normally. Which conclusion is justified?

7. A flowering shoot forming an inflorescence follows which developmental order best represents the transition toward functional reproductive flowers?

8. A chasmogamous bisexual flower has perfectly overlapping pollen release and stigma receptivity, but a developmental change places its anthers far from its own stigma. An insect nevertheless carries its pollen to another flower on the same plant. Which interpretation is most accurate?

9. In a developing endosperm, repeated divisions of the primary endosperm nucleus continue normally, but wall formation around the daughter nuclei is experimentally delayed. Which condition should persist longer than usual?

10. Seeds of a plant are viable, well protected and well supplied with reserves, but a mutation eliminates their ability to remain dormant. Whenever brief rainfall occurs, they germinate immediately even if a prolonged unfavourable season follows. Which reproductive advantage is most directly reduced?

11. An insect deliberately transfers pollen within a Yucca flower and then deposits eggs in the ovary. Successful reproduction of the plant and the insect are closely associated with these behaviours. This interaction is best classified as:

12. Trait variance is measured in descendants of the same hybrid over four generations.

Which inference is most consistent with the reproductive mechanisms?

13. In a hypothetical mutant embryo sac, three separate polar nuclei are present in the central cell instead of the normal two. Each is haploid, and one normal haploid male gamete fuses simultaneously with all three. What ploidy would the resulting central-cell fusion product have?

14. Which developmental order best represents the usual relation between the two principal products of double fertilisation?

15. Match each seed condition with the corresponding fate of endosperm. Each Column II entry is used once.

16. Four fusion records from an embryo sac are shown below.

Which pair represents the two normal components of double fertilisation?

17. A pollen mother cell completes nuclear division, but chromosome-set reduction fails, so its products retain the diploid chromosome set. Relative to normal microsporogenesis, the immediate abnormality is that:

18. Endosperm conditions in a developing coconut are summarised below.

Which interpretation is correct?

19. Five flowers each contain an ovary with one ovule, while two additional flowers each contain an ovary with ovules. If every ovule in all seven flowers ultimately forms one seed, the total number of seeds produced is:

20. Match each embryo-sac component with its normal location. Each Column II entry is used once.

21. A mutant anther completes normal meiosis in all pollen mother cells, producing haploid microspore tetrads, but the four microspores within each tetrad fail to separate during maturation. Which conclusion best follows?

22. A seed contains one normal zygotic embryo and several additional embryos, yet genetic tracing shows that the extra embryos match maternal nucellar tissue rather than the fertilised egg. Which conclusion is strongest?

23. In an embryo sac, one discharged male gamete successfully fuses with the egg, while the second male gamete is experimentally prevented from entering the central-cell fusion. Which product can still form directly from the successful event?

24. In a wind-pollinated plant, distance from a pollen source is plotted on the horizontal axis and the mean number of pollen grains intercepted per receptive stigma on the vertical axis. At , the means are grains respectively. Other conditions are kept similar. Which interpretation is best supported?

25. Arrange the following events in the normal development of the common monosporic female gametophyte.
P. One megaspore remains functional while three degenerate
Q. A diploid megaspore mother cell differentiates in the nucellus
R. Three successive mitoses produce an eight-nucleate stage
S. Meiosis produces four haploid megaspores
T. Cellular organisation establishes a -celled, -nucleate embryo sac

26. Match each part of a typical dicot embryo with its correct positional or structural description. Each Column II entry is used once.

27. A primary endosperm nucleus undergoes many rounds of nuclear division, but a mutation blocks cytokinesis throughout the observed period. Which tissue condition should predominate?

28. A bisexual flower normally releases pollen well before its stigma becomes receptive. A mutation changes the flower so that pollen release now overlaps fully with stigma receptivity, while anther and stigma remain close together. What is the most direct consequence?

29. During development of a non-albuminous dicot seed, most endosperm is progressively consumed while the cotyledons enlarge and become rich in stored nutrients. Which interpretation best explains the mature condition?

30. Suppose the outer three wall layers of a developing microsporangium are severely disrupted, while the tapetum and sporogenous tissue remain initially intact. Which process is most directly expected to be compromised at the anther level?

31. Starting with the nucleus of one functional megaspore, which sequence represents the usual free-nuclear development leading to the common mature embryo sac?

32. Consider the following ovary records.

Assuming every ovule is successfully fertilised and matures normally, which conclusion follows?

33. A retained tissue in a mature seed is traced developmentally to the nucellus that surrounded the embryo sac before fertilisation. This tissue should be classified as:

34. Embryos from one Citrus seed are traced to their developmental origins.

Which interpretation best fits the seed?

35. Two mature fruits differ strongly in texture. Fruit P has a fleshy pericarp, while Fruit Q has a dry pericarp. Developmental tracing shows that in both cases the pericarp arose from the ovary wall after normal fertilisation. Which relationship is best supported?

36. A mature seed contains the following tissues: a diploid seed coat, a diploid embryo, a triploid endosperm and a small amount of persistent diploid nucellus. Which statement correctly distinguishes their developmental origins?

37. Consider the following statements about xenogamy.
I. Pollen is transferred between flowers on different plants of the same species.
II. It introduces pollen from a genetically different individual to the recipient stigma.
III. It is distinct from geitonogamy even if the same pollinating agent can perform both transfers.
IV. It always occurs within a single bisexual flower.

38. After two successive mitotic divisions of a functional megaspore nucleus, microscopy shows four nuclei within a common cytoplasmic region and no wall separating each nucleus into an individual cell. This observation represents:

39. Match each wind-pollination feature with its principal functional significance. Each Column II entry is used once.

40. Arrange the following events in the surface-pollination mechanism of Vallisneria.
P. Water movement brings male material into contact with the female flower
Q. The female flower reaches the water surface on a long stalk
R. Male flowers or pollen become available at the water surface
S. Pollen reaches the receptive female reproductive structure

41. Consider the following statements about polar nuclei and antipodal cells.
I. The two polar nuclei are located in the large central cell.
II. Three antipodal cells occur at the chalazal end.
III. Each polar nucleus occupies a separate central cell.
IV. Antipodal cells form the micropylar egg apparatus.

42. An anther contains pollen mother cells that all complete normal meiosis, and every meiotic product survives as a separate microspore. What is the expected number and ploidy of the resulting microspores?

43. In a dioecious papaya population, pollen from a male plant reaches a receptive flower on a female plant of the same species. Among the standard pollen-transfer categories, how should this event be classified?

44. Match each reproductive term with the observation that best identifies it. Each Column II entry is used once.

45. A flower receives no pollen and fertilisation does not occur, yet its ovary enlarges and develops into a mature seedless fruit. The developmental phenomenon is:

46. A grass-like plant bears many small flowers in a compact inflorescence. Stamens are exposed, pollen is light and non-sticky, and the stigmas are large and feathery. Each ovary contains a single ovule. Which reproductive interpretation best fits this trait combination?

47. Two Ophrys flower forms are tested. Form P retains the floral appearance and signals that mimic a female bee. Form Q has those signals experimentally altered while nectar production and pollen viability remain unchanged. Male-bee pseudocopulatory visits and successful pollen transfer fall sharply in Q. What is the strongest inference?

48. An ovule completes double fertilisation normally. Endosperm develops rapidly and abundantly, but the zygote is experimentally prevented from undergoing any mitotic division. Which outcome is most directly expected?

49. In a species with , a mature seed contains a diploid nucellar embryo and triploid endosperm. How many chromosomes are expected in each respectively?

50. A mature seed has a hardened outer coat traced to the ovular integuments, a small persistent pore in that coat and an embryo containing an embryonal axis with cotyledonary tissue. Which developmental interpretation fits all three observations?