SEXUAL REPRODUCTION IN FLOWERING PLANTS CLASS XII

 

GANGWAR SIR BAREILLY

BIOLOGY

Class: 12 (2025-26)

CLASS TEST

TIME: 2 HOURS	M.M.: 55

General Instructions:

• This question paper contains 24 questions.

• All questions are compulsory.

• Q.1 to 5 (Multiple Choice Questions (MCQs)): 5 questions. Each question carries 1 mark.

• Q.6 to 7 (Assertion Reason Questions): 2 questions. Each question carries 1 mark.

• Q.8 to 11 (Very Short Answer Questions): 4 questions. Each question carries 1 mark.

• Q.12 to 18 (Short Answer Questions): 7 questions. Each question carries 2 marks.

• Q.19 to 22 (Long Answer Questions): 4 questions. Each question carries 5 marks.

• Q.23 to 23 (Competency Based Questions): 1 questions. Each question carries 5 marks.

• Q.24 to 24 (Comprehension Based Questions): 1 questions. Each question carries 5 marks.

Topics Covered:

• Sexual Reproduction in Flowering Plants

 

Q.NO.	QUESTIONS	MARKS
MULTIPLE CHOICE QUESTIONS (MCQS) Questions 1 to 5 (5 questions × 1 mark each)
1	In angiosperms, the embryo sac develops from the functional megaspore through mitotic divisions. What is the ploidy level of the central cell before fertilization in a typical Polygonum-type embryo sac? A. Haploid (n) B. Diploid (2n) C. Triploid (3n) D. Tetraploid (4n)	1
2	In the process of emasculation in flowering plants, which of the following steps is critical to prevent self-pollination? A. Removal of stamens before anthesis B. Application of auxin to the stigma C. Cutting off the petals after pollination D. Covering the flower with a plastic bag	1
3	In flowering plants, which of the following is NOT an outbreeding device to prevent self-pollination? A. Production of unisexual flowers B. Dichogamy where anthers and stigma mature at different times C. Heterostyly with styles of different lengths D. Production of cleistogamous flowers that never open	1
4	In angiosperms, megasporogenesis involves the formation of megaspores from megaspore mother cells. Which of the following statements accurately describes the fate of the megaspores during this process? A. All four megaspores develop into functional megagametophytes B. Three megaspores degenerate, and one develops into the functional megagametophyte C. Two megaspores fuse to form a diploid zygote D. The megaspores undergo mitosis to form an eight-nucleate embryo sac	1
5	In angiosperms, the primary endosperm nucleus (PEN) is triploid because it: A. Results from the fusion of two polar nuclei with one sperm nucleus B. Is formed by the fusion of three haploid egg cells C. Develops from the diploid zygote through mitotic divisions D. Arises from the fusion of a sperm nucleus with the synergid nucleus	1
ASSERTION REASON QUESTIONS Questions 6 to 7 (2 questions × 1 mark each) Instructions: The following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below: A. Both A and R are true, and R is the correct explanation of A. B. Both A and R are true, and R is not the correct explanation of A. C. A is true but R is false. D. A is false but R is true.
6	Assertion (A): The pollen grain wall contains sporopollenin which is chemically inert and resistant to degradation.  Reason (R): Sporopollenin protects the pollen grain from environmental factors such as UV radiation and microbial attack.	1
7	Assertion (A): The integuments of the ovule develop into the seed coat after fertilization.  Reason (R): The integuments provide mechanical protection to the developing embryo.	1
VERY SHORT ANSWER QUESTIONS Questions 8 to 11 (4 questions × 1 mark each)
8	In angiosperms, what is the ploidy level of the tapetum and what is its primary function?	1
9	What is the role of coleoptile and coleorhiza in the germination of monocot seeds?	1
10	Name the type of gynoecium found in Michelia where carpels are many and free on the thalamus.	1
11	In Amorphophallus, where are the floral rewards typically located to ensure pollination by specific insects?	1
SHORT ANSWER QUESTIONS Questions 12 to 18 (7 questions × 2 marks each)
12	Explain the biological significance of parthenocarpic fruits in agriculture and horticulture.	2
13	Explain the significance of pollen-pistil interaction in preventing self-pollination and promoting cross-pollination.	2
14	Differentiate between albuminous and non-albuminous seeds with one example of each.	2
15	How does the formation of the embryo sac occur in flowering plants?	2
16	Discuss the role of synergids in the fertilization process of angiosperms.	2
17	Explain the significance of coconut water and coconut meat in relation to endosperm development.	2
18	Describe the structure of a grass embryo with reference to its essential parts.	2
LONG ANSWER QUESTIONS Questions 19 to 22 (4 questions × 5 marks each)
19	Discuss the significance of apomixis in flowering plants with respect to agricultural applications and genetic conservation. Explain how apomictic seeds differ from normal seeds in terms of their genetic constitution and developmental process.	5
20	Describe the structure and function of the pollen grain in flowering plants. How does it contribute to the process of pollination?	5
21	Explain the mechanisms of wind pollination in plants, highlighting the structural adaptations that facilitate this process. How do these adaptations differ from those seen in water-pollinated plants? Discuss the ecological significance of wind pollination in plant reproduction.	5
22	(a) Differentiate between cleistogamous and chasmogamous flowers with suitable examples. (b) Explain the differences between geitonogamy and xenogamy with reference to their genetic consequences.	5
COMPETENCY BASED QUESTIONS Questions 23 to 23 (1 questions × 5 marks each)
23	A botanist observed that in a population of cross-pollinated flowering plants, certain individuals consistently produced seeds with higher germination rates despite similar environmental conditions. Upon microscopic examination, it was found that these plants had a unique pollen tube growth pattern where multiple pollen tubes entered the same ovule. The researcher hypothesized that this phenomenon might be linked to a specific genetic adaptation in the pistil. A. Analyze how the observed multiple pollen tube entry could provide a selective advantage to these plants. B. Evaluate the potential consequences of this adaptation on the genetic diversity of the offspring. C. Create an experimental design to test whether this trait is genetically inherited or environmentally induced. D. Predict how this adaptation might affect the plant's reproductive success in a changing climate scenario. E. Critically assess whether this phenomenon could lead to the evolution of a new pollination mechanism.	5
COMPREHENSION BASED QUESTIONS Questions 24 to 24 (1 questions × 5 marks each)
24	Double Fertilization in Angiosperms Double fertilization is a unique feature of angiosperms, involving the fusion of one male gamete with the egg cell to form the zygote, while the other male gamete fuses with the two polar nuclei to form the triploid primary endosperm nucleus. This process ensures the formation of both the embryo and the endosperm, which serves as a nutrient-rich tissue for the developing embryo. The synergids and antipodal cells play supportive roles during fertilization. Understanding the intricacies of double fertilization is crucial for comprehending the reproductive strategies of flowering plants. (1) Explain the significance of the fusion of the male gamete with the polar nuclei. (2) Describe the role of synergids in the process of fertilization. (3) How does double fertilization contribute to the survival of the embryo? (4) Differentiate between the zygote and the primary endosperm nucleus. (5) Discuss the evolutionary advantage of double fertilization in angiosperms.	5