NEET Biology Sexual Reproduction in Flowering Plants Important Questions Set 01

These Class 12 NEET Biology important questions on Sexual Reproduction in Flowering Plants give 45 questions with step-by-step answers, arranged as very short, short and long answer types, as asked in school and board examinations. They help NEET aspirants revise the definitions, structures, differences and key terms of the chapter.

Very Short Answer Type Questions

Question 1. Name the fertile whorls of a flower.
Answer: Androecium and gynoecium

Question 2. Define tetrasporangiate condition in an anther.
Answer: Tetrasporangiate means presence of four microsporangia in an anther.

Question 3. Name the wall layers of anther.
Answer: Epidermis, endothecium, middle layers and tapetum.

Question 4. What is the ploidy level of cells in a microspore tetrad?
Answer: Haploid

Question 5. What is the function of germ pore?
Answer: To help in the exit of pollen tube.

Question 6. What is the function of pollen banks?
Answer: Pollen bank helps in cryopreservation of pollen in liquid nitrogen (–196°C) which is further used in crop breeding programmes.

Question 7. What is the ploidy level of the cells in a female gametophyte?
Answer: Haploid

Question 8. In which type of plants both autogamy and geitonogamy are prevented?
Answer: Dioecious plants like papaya.

Question 9. Which type of plants are emasculated in artificial hybridisation experiments?
Answer: Female parents which have bisexual flowers.

Question 10. What type of endosperm is represented by coconut water?
Answer: Free nuclear endosperm

Short Answer Type Questions

Question 11. What are perispermic seeds? Give examples.
Answer: Seeds with remnants of nucellus which perform nutritive function. Examples - Black pepper and beet

Question 12. Which two properties of seeds are crucial for storage?
Answer: Dehydration and dormancy

Question 13. List two features of pollen grains of flowers of maize plant.
Answer: Pollen grains are :
(i) Light and non-sticky.
(ii) Produced in large number.

Question 14. Mention the name of outer pollen wall. What is its chemical composition?
Answer: Exine. It is made of sporopollenin.

Question 15. What is inbreeding depression?
Answer: Inbreeding depression means decrease in vigour of plants due to continuous self-pollination.

Question 16. What is seed dormancy? What conditions are required for seed germination?
Answer: Failure of the seed to germinate due to metabolic inactivity of embryo is called as seed dormancy. Conditions for seed germination :
(i) Adequate moisture
(ii) Oxygen
(iii) Suitable temperature

Question 17. Mention the name of layer of anther wall having high DNA content. What is the ploidy level of innermost wall of anther?
Answer: The innermost wall layer is tapetum. The cells of this layer are polyploid.

Question 18. Define ovule. Which part of ovule has abundant reserve food?
Answer: Ovule is integumented megasporangium. Nucellus has abundant food reserves.

Question 19. Differentiate between xenogamy and autogamy.

Answer:

Question 20. Write a short note on pollen reward.
Answer: Pollen rewards are provided to pollinating agents by the plants to sustain their visits. It includes :
(i) Nectar
(ii) Pollen grains
(iii) Safe place to lay eggs, for example, Amorphophallus.

Question 21. List any three devices in plants to discourage self-pollination and to encourage cross-pollination. Explain the importance of each.
Answer: Three outbreeding devices in plants :
(i) Difference in maturation time of pollen and stigma or pollen release and stigma receptivity are not synchronised.
(ii) Anther and stigma are placed at different position so that the pollen cannot come in contact with the stigma of the same flower.
(iii) Self-incompatibility : It is a genetic mechanism that prevents self-pollen from fertilising the ovules by inhibiting pollen germination or pollen tube growth in the pistil.

Question 22. Why is apple referred as false fruits? How are they different from parthenocarpic fruits?
Answer: Apple is referred as false fruit because thalamus take part in fruit formation in addition to the ovary. Parthenocarpic fruits are formed without fertilisation. Hence, they are seedless.

Question 23. How apomixis is differ from polyembryony?
Answer: Apomixis : It is a type of asexual reproduction that mimics sexual reproduction. It takes places without fusion of gametes. Polyembryony : Occurrence of more than one embryo in a seed.

Question 24. Draw a vertical section of seed of onion and label the different parts.
Answer: A well-labelled diagram should show these parts: Onion seed.

Question 25. Why is bagging of emasculated flowers essential during hybridisation experiments?
Answer: Covering of flowers on female parent with a polythene bag is called bagging. It prevents contamination of stigma with foreign pollen grains.

Question 26. Name the cell from which endosperm of coconut develops. Give the characteristic features of endosperm of coconut.
Answer: PEC (primary endosperm cell) forms the endosperm. Coconut has two types of endosperm :
(i) Free nuclear : Liquid endosperm
(ii) Cellular endosperm : White solid endosperm

Question 27. What are the main differences between microsporogenesis and megasporogenesis?

Answer:

Question 28. Discuss the distribution of cells within a mature embryo sac.

Answer:

A typical mature embryo sac is 7-celled and 8-nucleate. The 8-nuclei have characteristic 3 + 2 + 3 arrangement.

(i) Egg apparatus consisting of two synergid cells and an egg cell at micropylar end.

(ii) Two polar nuclei within large central cell.

(iii) Three antipodal cells at chalazal end.

Question 29. What are the advantages of fertilised ovule to angiosperms?

Answer:

Advantages of seed to angiosperms :

(i) Seed often better adaptive strategies for dispersal to new habitat and help the species to colonise the other areas.

(ii) They have sufficient food reserves young seedlings are nourished until they are capable of photosynthesis on their own.

(iii) The hard seed coat provides protection to young embryo.

(iv) They generate new genetic combinations leading to variations.

Question 30. Explain what is double fertilisation. In which category of plants does it occur?

Answer:

Double fertilisation involves two types of fusions in embryo sac.

(i) Syngamy : Fusion of one male gamete with egg cell to form a zygote.

(ii) Triple fusion : Fusion of a male gamete with secondary nucleus to form primary endosperm nucleus (PEN) which form future endosperm. It serves as a nutritive tissue for developing embryo.

Long Answer Type Questions

Question 31. (a) Draw a well-labelled diagram representing L.S. of monocot embryo.
(b) Endosperm development precedes embryo development. Explain.

Answer:

(a)

(b) Endosperm development starts before embryo development to provide assured nutrition to the developing embryo.

Question 32. Illustrate the stages with labelled diagram for pollen developing into a mature pollen grain.

Answer:

Exine Intine Microspore

Vacuoles

Nucleus

Asymmetric spindle

Vegetative cell

Generative cell

Question 33. (a) Name the type of flowers which may cause inbreeding depression.
(b) List the abiotic agents required for cross pollination.
(c) State three differences between flowers pollinated by these abiotic agents and flowers pollinated by biotic agents.

Answer:

(a) Cleistogamous flowers, bisexual flowers with homogamous condition.
(b) Wind, water (c) S.No. Flowers pollinated Flowers pollinated by abiotic agents by biotic agents

1. Flowers inconspicuous. Flowers large and showy.
2. No smell and nectar. Flowers are variously smelled and produce nectar.
3. Pollen grains light and non-sticky. Pollen sticky.

Question 34. (a) If the leaf cell of an angiospermic plant contain 18 chromosomes, what would be the chromosome number and ploidy level of (i) Megaspore mother cell (MMC) and (ii) Endosperm cell.
(b) Name the cell that develops into embryo sac.
(c) What is the role of synergids in embryo sac?

Answer:

(a) Leaf cells are diploid, so 2n = 18.

(b) Functional megaspore
(c) Synergids have special cellular thickenings at micropylar tip called filiform apparatus which play an important role in guiding the pollen tube into the synergid. Synergid is the site for pollen tube discharge.

Question 35. (a) Which type of ovule is shown in the figure? Give one reason.
(b) What is the function of funicle?
(c) What are the protective layers of this structure?
(d) Where is the megaspore mother cell (MMC) seen in this structure? How many MMC differentiate?
Answer: (a) Anatropous ovule. The funiculus lie close to micropyle. It is inverted ovule.
(b) It serves a stalk of ovule which attaches it to the placenta.
(c) Two protective layers called as integuments.
(d) Ovules generally differentiates a single megaspore mother cell in the micropylar region of the nucellus.

Question 36. State whether the following statements are true or false. Correct each false statement to make it true.
(a) Apomixis mimics sexual reproduction because there is syngamy.
(b) Development of fruits without fertilisation is called parthenogenesis.
(c) The function of tapetum is to help in the dehiscence of anther.
(d) The pollen viability in members of Solanaceae family is 30 minutes.
(e) Coleoptile is a sheath enclosing shoot tip.
Answer: (a) False (No syngamy).
(b) False (Parthenocarpy).
(c) False (Nutritive).
(d) False (Few months).
(e) True.

Question 37. Briefly describe the following :
(a) Polyembryony
(b) Triple fusion

Answer:

A well-labelled diagram should show these parts: Integument; Nucellus; Zygotic embryo; Endosperm; Nucellar embryo; Integumentary embryo; The embryos shown are; 1. Zygotic; 2. Nucellar; 3. Integumentary; (b) Triple fusion :; +; Two fused; PEN polar nuclei; Primary; Male(n)gamete; (2n) endosperm nucleus.

(a) Polyembryony : Occurrence of more than one embryo in a seed is referred as polyembryony. The diagram above shows several embryo formation in Citrus.

The nucellar and integumentary embryos are apomictic. The genetic nature of these embryo is diploid (2n) and they would be genetically identical to each other and can be called as a clone.

One of the male gametes moves towards the two polar nuclei located in the central cell and fuses with them to produce a triploid primary endosperm nucleus (PEN).

Question 38. F E D
G C
B
A With respect to the above diagram answer the following questions :
(a) Label A to G.
(b) Name the non-essential whorls of the flower.
(c) Which structure forms the pollen grains?
(d) Inside which structure are integumented megasporangia present?
(e) State the function of non-essential whorls.
Answer: (a) A - Ovary B - Sepal C - Filament D - Petal E - Anther F - Stigma G - Style
(b) Calyx and corolla
(c) Androecium
(d) Ovary
(e) Calyx and corolla are non-essential whorls which help in the protection of flower during bud stage and attracting insects for pollination respectively.

Question 39. (A) (B)
(a) What type of conditions with reference to gynoecium are shown in the diagrams given below?
(b) Differentiate between condition (A) and (B) and state one example of each.
(c) Give examples of plants where single ovule is present in ovary.

Answer:

(a) (A) Syncarpous pistil (B) Multicarpellary apocarpous gynoecium (b)

(c) Wheat, paddy, mango.

Question 40. With reference to the above figure answer the following questions :
(a) Which cells make up the egg apparatus?
(b) What is the function of filiform apparatus?
(c) Which is the largest cell? Mention the type of fusion which takes in this cell.
(d) How many mitotic generations are required to obtain the condition as seen in the above diagram?
Answer: (a) Two synergids + one egg cell
(b) To facilitate the entry of pollen tube
(c) Central cell, triple fusion and syngamy
(d) Three

Question 41. A B
C
With reference to the above figure answer the following :
(a) Label A, B, C.
(b) Which cell forms the future nutritive tissue. Define the process by which it is formed.
(c) What is formed by structure labelled B?
Answer: (a) A - Degenerating synergids B - Zygote C - Degenerating antipodal cells
(b) Primary endosperm cell. Triple fusion is fusion of one male gamete with secondary nucleus leading to the formation of PEN.
(c) Embryo is formed.

Question 42. Differentiate between :
(a) Albuminous and exalbuminous seed
(b) Radicle and plumule
(c) Coleoptile and coleorhiza
(d) Pericarp and seed coat

Answer:

(a) Albuminous seed Exalbuminous seed Seeds where endosperm is present Seeds where endosperm is at maturity. consumed at maturity. Example - Castor, barley, wheat, Example - Pea, groundnut sunflower

(b) Radicle Plumule The portion of embryonal axis below The portion of embryonal axis above the level of cotyledons is hypocotyl the level of cotyledons is the that terminates at its lower end in the epicotyl, which terminates with the radicle. plumule. (c) Coleoptile Coleorhiza In a monocot embryo, the shoot In a monocot embryo, the radicle apex and few leaf primordia are and root cap are enclosed in an enclosed in a hollow foliar structure undifferentiated sheath called called coleoptile. coleorhiza. (d) Pericarp Seed coat The wall of the fruit is called pericarp. The wall of the seed is called seed It formed by the wall of the ovary. coat. I t is f ormed by t he integument(s) of ovule.

Question 43. Fill in the blanks :
(a) Coconut water is made up of thousands of _________.
(b) Black pepper and beet have _________ seeds.
(c) Seedless banana is an example of _________ fruit.
(d) Pollen pistil interaction is a _________ process involving pollen recognition followed by promotion or inhibition of the pollen.
(e) Outbreeding device in castor plant prevents _________ but not _________.
Answer: (a) Nuclei
(b) Perispermic
(c) Parthenocarpic
(d) Dynamic
(e) Autogamy, geitonogamy

Question 44.

Find out the wrongly matched pairs and correct each wrong pair to make it correct.

Answer:

c, f, h, i, j
(c) High DNA content
(f) Entomophily
(h) Chasmogamy
(i) Endosperm
(j) Diploid structure

Question 45. (a) Which type of pollination is less common in hydrophytes?
(b) What adaptation is seen in pollen grains of hydrophilous species?
(c) What is self-incompatibility?
(d) What is epiblast?
(e) What does mean by hilum in ovule?
Answer: (a) Hydrophily
(b) Pollen grains are protected by from wetting by a mucilaginous covering.
(c) A genetic mechanism which prevents self-pollen from the same flower or other flowers of the same plant from fertilising the ovules by inhibiting pollen germination or pollen tube growth in the pistil.
(d) Epiblast is the remain of second cotyledon in monocots.
(e) It represents the junction between ovule and funicle.