Chapter 2: Sexual Reproduction in Flowering Plants – MCQs with Answers & Explanations
CBSE Class 12 Biology – MCQs with Answers and Explanations
Unit I: Reproduction | Chapter 2: Sexual Reproduction in Flowering Plants (NCERT Based)
Course & Examination Details
- Course: CBSE Class 12 Biology
- Prescribed By: Central Board of Secondary Education
- Syllabus Source: NCERT
- Unit: Unit I – Reproduction
- Chapter: Chapter 2 – Sexual Reproduction in Flowering Plants
- Exam Focus: CBSE Class 12 Board Examinations (Objective & Competency-Based MCQs)
CBSE Class 12 Biology Chapter 2 MCQs with Answers & Explanations – Sexual Reproduction in Flowering Plants (NCERT)
Section A: Flower as a Reproductive Organ
Q1. The flower is considered a modified shoot because:
A. It bears leaves
B. It develops from axillary bud
C. It has limited growth
D. It bears reproductive organs
Correct Answer: D
Explanation: A flower is a modified shoot specialised for sexual reproduction, bearing androecium and gynoecium.
Q2. Which floral whorl is directly involved in reproduction?
A. Calyx
B. Corolla
C. Androecium and gynoecium
D. Thalamus
Correct Answer: C
Explanation: Androecium produces male gametes and gynoecium produces female gametes.
Q3. A flower having both male and female organs is called:
A. Unisexual
B. Bisexual
C. Sterile
D. Incomplete
Correct Answer: B
Explanation: Bisexual flowers possess both androecium and gynoecium.
Q4. Which floral part mainly attracts pollinators?
A. Sepals
B. Petals
C. Stamens
D. Ovary
Correct Answer: B
Explanation: Petals are often brightly coloured and scented to attract pollinators.
Section B: Structure of Stamen and Carpel
Q5. A typical anther is:
A. Unilobed
B. Bilobed
C. Trilobed
D. Multilobed
Correct Answer: B
Explanation: Each anther has two lobes, each containing two pollen sacs.
Q6. How many microsporangia are present in a typical anther?
A. One
B. Two
C. Three
D. Four
Correct Answer: D
Explanation: Each anther has four microsporangia arranged in two lobes.
Q7. The nutritive layer of the anther wall is:
A. Epidermis
B. Endothecium
C. Middle layers
D. Tapetum
Correct Answer: D
Explanation: Tapetum provides nourishment to developing pollen grains.
Q8. Which part of carpel receives pollen grains?
A. Ovary
B. Style
C. Stigma
D. Placenta
Correct Answer: C
Explanation: Stigma is sticky and receives pollen during pollination.
Section C: Microsporogenesis and Pollen Grain
Q9. Microsporogenesis involves:
A. Mitosis
B. Meiosis
C. Fertilisation
D. Pollination
Correct Answer: B
Explanation: Microspore mother cells undergo meiosis to form haploid microspores.
Q10. The outer wall of pollen grain is made of:
A. Cellulose
B. Pectin
C. Sporopollenin
D. Lignin
Correct Answer: C
Explanation: Sporopollenin provides extreme resistance to pollen grains.
Q11. Pollen grains are resistant due to:
A. Intine
B. Exine
C. Vegetative cell
D. Generative cell
Correct Answer: B
Explanation: Exine contains sporopollenin, making pollen highly durable.
Q12. The generative cell of pollen grain forms:
A. Pollen tube
B. Two male gametes
C. Endosperm
D. Synergids
Correct Answer: B
Explanation: The generative cell divides to form two male gametes.
Section D: Megasporogenesis and Embryo Sac
Q13. Megasporogenesis occurs inside:
A. Anther
B. Ovary
C. Ovule
D. Stigma
Correct Answer: C
Explanation: Megaspore mother cell inside ovule undergoes meiosis.
Q14. How many megaspores are formed initially?
A. One
B. Two
C. Three
D. Four
Correct Answer: D
Explanation: Four megaspores are formed, but only one remains functional.
Q15. A typical embryo sac is:
A. 8-celled, 8-nucleate
B. 7-celled, 8-nucleate
C. 8-celled, 7-nucleate
D. 7-celled, 7-nucleate
Correct Answer: B
Explanation: Embryo sac has seven cells but eight nuclei.
Q16. Which cells guide the pollen tube?
A. Antipodals
B. Polar nuclei
C. Synergids
D. Egg cell
Correct Answer: C
Explanation: Synergids secrete chemicals guiding pollen tube entry.
Section E: Pollination
Q17. Pollination is transfer of pollen from:
A. Stigma to ovary
B. Ovary to anther
C. Anther to stigma
D. Pollen tube to ovule
Correct Answer: C
Explanation: Pollination precedes fertilisation by transferring pollen to stigma.
Q18. Xenogamy involves pollination between:
A. Same flower
B. Different flowers of same plant
C. Different plants of same species
D. Different species
Correct Answer: C
Explanation: Xenogamy promotes genetic variation.
Q19. Pollination by insects is called:
A. Anemophily
B. Hydrophily
C. Entomophily
D. Ornithophily
Correct Answer: C
Explanation: Entomophily involves insects as pollinators.
Q20. Which is NOT an outbreeding device?
A. Dichogamy
B. Herkogamy
C. Self-incompatibility
D. Autogamy
Correct Answer: D
Explanation: Autogamy promotes self-pollination, not outbreeding.
Section F: Double Fertilisation
Q21. Double fertilisation is unique to:
A. Bryophytes
B. Gymnosperms
C. Angiosperms
D. Pteridophytes
Correct Answer: C
Explanation: Only angiosperms show double fertilisation.
Q22. Syngamy results in formation of:
A. Endosperm
B. Zygote
C. Ovule
D. Embryo sac
Correct Answer: B
Explanation: Fusion of male gamete and egg forms zygote.
Q23. Triple fusion forms:
A. Diploid tissue
B. Haploid tissue
C. Triploid endosperm
D. Zygote
Correct Answer: C
Explanation: Fusion of male gamete with two polar nuclei forms triploid endosperm.
Q24. The primary endosperm nucleus is:
A. Haploid
B. Diploid
C. Triploid
D. Tetraploid
Correct Answer: C
Explanation: It contains three sets of chromosomes.
Section G: Post-Fertilisation Changes
Q25. Endosperm develops from:
A. Zygote
B. Polar nuclei
C. Primary endosperm nucleus
D. Antipodals
Correct Answer: C
Explanation: Primary endosperm nucleus divides to form endosperm.
Q26. The most common type of endosperm development is:
A. Cellular
B. Helobial
C. Nuclear
D. Adventive
Correct Answer: C
Explanation: Nuclear endosperm shows free nuclear divisions initially.
Q27. The fertilised ovule develops into:
A. Fruit
B. Seed
C. Embryo
D. Endosperm
Correct Answer: B
Explanation: Ovule transforms into seed after fertilisation.
Q28. Ovary develops into:
A. Seed
B. Embryo
C. Fruit
D. Endosperm
Correct Answer: C
Explanation: Ovary matures into fruit enclosing seeds.
Section H: Embryo Development
Q29. Dicot embryo has:
A. One cotyledon
B. Two cotyledons
C. No cotyledon
D. Many cotyledons
Correct Answer: B
Explanation: Dicot embryos contain two cotyledons.
Q30. Scutellum is found in:
A. Dicot embryo
B. Monocot embryo
C. Gymnosperm
D. Bryophyte
Correct Answer: B
Explanation: Scutellum is a modified cotyledon in monocots.
Section I: Seed and Fruit Formation
Q31. Seed coat develops from:
A. Ovary wall
B. Endosperm
C. Integuments
D. Nucellus
Correct Answer: C
Explanation: Integuments form testa and tegmen of seed coat.
Q32. A fruit formed from ovary and thalamus is:
A. True fruit
B. False fruit
C. Parthenocarpic fruit
D. Dry fruit
Correct Answer: B
Explanation: False fruits involve additional floral parts.
Q33. Which structure helps in seed germination by allowing water entry?
A. Hilum
B. Micropyle
C. Testa
D. Tegmen
Correct Answer: B
Explanation: Micropyle allows water absorption during germination.
Section J: Apomixis and Polyembryony
Q34. Apomixis involves:
A. Double fertilisation
B. Seed formation without fertilisation
C. Vegetative propagation
D. Polyploidy
Correct Answer: B
Explanation: Apomixis bypasses fertilisation.
Q35. Apomixis is useful because it:
A. Produces variation
B. Preserves hybrid characters
C. Reduces yield
D. Prevents seed formation
Correct Answer: B
Explanation: Apomixis maintains hybrid vigour.
Q36. Polyembryony refers to:
A. Many seeds in fruit
B. Many fruits from flower
C. Many embryos in one seed
D. Many ovules in ovary
Correct Answer: C
Explanation: Polyembryony is presence of multiple embryos in a seed.
Q37. Polyembryony is commonly seen in:
A. Wheat
B. Rice
C. Citrus
D. Pea
Correct Answer: C
Explanation: Citrus commonly shows adventive polyembryony.
Section K: Higher-Order Conceptual MCQs
Q38. Genetic variation is maximum in:
A. Autogamy
B. Geitonogamy
C. Xenogamy
D. Apomixis
Correct Answer: C
Explanation: Xenogamy involves different plants, increasing variation.
Q39. Outbreeding devices are adaptations to:
A. Increase self-pollination
B. Prevent fertilisation
C. Promote cross-pollination
D. Reduce pollen production
Correct Answer: C
Explanation: They ensure genetic diversity.
Q40. Sexual reproduction is advantageous because it:
A. Is rapid
B. Produces clones
C. Generates variation
D. Requires one parent
Correct Answer: C
Explanation: Variation improves adaptability.
Q41. Which structure first receives pollen tube?
A. Ovule
B. Style
C. Micropyle
D. Synergid
Correct Answer: D
Explanation: Pollen tube enters embryo sac through synergid.
Q42. Endosperm is absent in mature seeds of:
A. Wheat
B. Maize
C. Pea
D. Castor
Correct Answer: C
Explanation: Pea is a non-endospermic seed.
Q43. Which division occurs during embryo development?
A. Meiosis
B. Amitosis
C. Mitosis
D. Reduction division
Correct Answer: C
Explanation: Embryo grows through mitotic divisions.
Q44. Transfer of pollen between flowers of same plant is:
A. Autogamy
B. Xenogamy
C. Geitonogamy
D. Apomixis
Correct Answer: C
Explanation: Geitonogamy requires pollinating agents.
Q45. Tapetum contributes to pollen wall formation by supplying:
A. Cellulose
B. Lignin
C. Sporopollenin precursors
D. Cutin
Correct Answer: C
Explanation: Tapetum provides materials for exine formation.
Q46. The ploidy of embryo is:
A. Haploid
B. Diploid
C. Triploid
D. Tetraploid
Correct Answer: B
Explanation: Embryo develops from diploid zygote.
Q47. Primary endosperm nucleus divides to form:
A. Embryo
B. Seed coat
C. Endosperm
D. Ovule
Correct Answer: C
Explanation: Endosperm nourishes embryo.
Q48. Which prevents self-pollination in bisexual flowers?
A. Dichogamy
B. Autogamy
C. Apomixis
D. Parthenocarpy
Correct Answer: A
Explanation: Dichogamy separates timing of male and female maturity.
Q49. The function of fruit is to:
A. Produce pollen
B. Nourish embryo
C. Protect and disperse seeds
D. Carry ovules
Correct Answer: C
Explanation: Fruits aid seed protection and dispersal.
Q50. Ultimate significance of sexual reproduction in flowering plants is:
A. Faster multiplication
B. Reduced variation
C. Species continuity with adaptability
D. Vegetative growth
Correct Answer: C
Explanation: Sexual reproduction ensures survival through variation and adaptation.
CBSE Board Exam Note
These 50 NCERT-based MCQs with detailed explanations are fully aligned with CBSE Class 12 Biology board exam standards, ideal for objective questions, competency-based assessments, and revision practice.
Targeting Exams
This MCQ-based practice set is useful for preparing:
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CBSE Class 12 Biology Board Examinations
-
CBSE Objective & Competency-Based Questions
-
School Unit Tests and Pre-Board Exams
-
NEET (UG) – Plant Reproduction Concepts
-
CUET (UG) Biology Entrance Examination
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