NEET DPP Biology Ch-24 Sexual Reproduction In Flowering Plants

Q.1. Entry of pollen tube through micropyle is
(a) Chalazogamy
(b) Mesogamy
(c) Porogamy
(d) Pseudogamy

Answer Answer:
(c) In porogamy the tip of pollen tube enters the micropyle, pushes through the nucellar tissue & finally pierces the eggapparatus end of the embryo sac. If pollen tube enters through the chalazal side it is called chalazogamy & if it enters laterally it is called mesogamy.

Q.2. Dry indehiscent single-seeded fruit formed from bicarpellary syncarpous inferior ovary is
(a) Caryopsis
(b) Cypsela
(c) Berry
(d) Cremocarp

Answer Answer:
(b) Dry indehiscent single-seeded fruit formed from bicarpellary syncarpous inferior ovary is cypsela. Cypsela is also called inferior, false or pseudocarpic achene, the thin fruit wall (developed from pericarp and thalamus)is attached to the seed at one point but the fruits develops from an inferior, unilocular and uniovuled ovary, e.g., sunflower, marigold. Some cypsela develop pappus for dispersal e.g. Sonchus, Taraxacum.

Q.3. One of the most resistant biological material is
(a) lignin
(b) hemicellulose
(c) lignocellulose
(d) sporopollenin

Answer Answer:
(d) Each pollen has two layered wall. The outer layer is thick, tough, cuticularised called exine which is composed of a material called “sporopollenin”. It is highly resistant to biological and physical decomposition, due to which pollens are preserved for a long time in fossils.

Q.4. When funiculum, chalaza, and micropyle lie in one straight line, then ovule is called –
(a) Amphitropous
(b) Orthotropous
(c) Campylotropous
(d) Anatropous

Answer Answer:

Q.5. Which one of the following is a fruit ?
(a) Ginger
(b) Sweet potato
(c) Radish
(d) Lady’s finger

Answer Answer:

Q.6. Female gametophyte of angiosperms is represented by
(a) Ovule
(b) Megaspore mother cell
(c) Embryo sac
(d) Nucellus

Answer Answer:
(c) Embryo sac is 7-celled structure. There is a large central cell with two polar nuclei, egg apparatus with egg cell and 2 synergids present at micropylar end and its chalazal end, 3 antipodal cells are present.

Q.7. Which of the following pair has haploid structures?
(a) Nucellus and antipodal cells
(b) Antipodal cells and egg cell
(c) Antipodal cells and megaspore mother cell
(d) Nucellus and primary endosperm nucleus

Answer Answer:

Q.8. Polyembryony commonly occurs in
(a) citrus
(b) turmeric
(c) tomato
(d) potato

Answer Answer:

Q.9. Chasmogamy refers to the condition where –
(a) Flowers remains closed
(b) Flowers are absent
(c) Flowers open
(d) Flowers gamopetalous

Answer Answer:

Q.10. In oogamy, fertilization involves
(a) a small non-motile female gamete and a large motile male gamete
(b) a large non-motile female gamete and a small motile male gamete
(c) a large non-motile female gamete and a small nonmotile male gamete
(d) a large motile female gamete and a small non-motile male gamete

Answer Answer:
(b) In oogamy male and female gametes are morphologically as well as physiologically different. Female gametes are large and non-motile. Male gametes are small but motile.

Q.11. Cotyledons and testa respectively are edible parts in
(a) walnut and tamarind
(b) french bean and coconut
(c) cashew nut and litchi
(d) groundnut and pomegranate

Answer Answer:

Q.12. A Polygonum type of embryo sac is
(a) 7-celled and 8-nucleate
(b) 8-celled and 7-nucleate
(c) 7-celled and 7-nucleate
(d) 8-celled and 8-nucleate

Answer Answer:

Q.13. In dicot embryo the radicle is formed by
(a) epibasal tier of embryo
(b) hypobasal tier of embryo
(c) hypophysis of suspensor
(d) terminal cell of suspensor

Answer Answer:

Q.14. A drupe develops in
(a) mango
(b) wheat
(c) pea
(d) tomato

Answer Answer:
(a) Some fleshy fruits such as mango, plum etc. usually have a single hard stone that encloses a seed, called drupe.

Q.15. When pollen grains are not transferred from anthers to stigma in a flower, due to the barrier, it is called
(a) herkogamy
(b) heterogamy
(c) cleistogamy
(d) dichogamy

Answer Answer:

Q.16. The parenchyma tissue which forms the bulk of ovule where the sporogenous tissue is produced is –
(a) Megaspore mother cell
(b) Nucellus
(c) Ovule
(d) Embryo sac

Answer Answer:

Q.17. Unisexuality of flowers prevents
(a) autogamy, but not geitonogamy
(b) both geitonogamy and xenogamy
(c) geitonogamy, but not xenogamy
(d) autogamy and geitonogamy

Answer Answer:
(a) Unisexuality of flowers prevents autogamy, but not geitonogamy. In self fertilisation , the male and female gametes are derived from the same individual. Among plants, self fertilization also called autogamy is common in many cultivated species, eg., wheat and oats. However, self fertilization is a form of inbreeding and does not allow for the mixing of genetic material; if it occurs over a number of generations it will result in offspring being less vigorous and productive than those resulting from cross fertilization.

Q.18. Which one of the following represents an ovule, where the embryo sac becomes horse-shoe shaped and the funiculus and micropyle are close to each other?
(a) Amphitropous
(b) Circinotropous
(c) Atropous
(d) Anotropous

Answer Answer:
(a) Amphitropous : Both body of ovule and embryo sac are curved. The embryo sac assumes horse-shoe shape. e.g. Papaveraceae.

Q.19. If an angiospermic male plant is diploid and female plant tetraploid, the ploidy level of endosperm will be
(a) haploid
(b) triploid
(c) tetraploid
(d) pentaploid

Answer Answer:

Q.20. These plants flower and fruit only once in their life time and die after fruiting. These are
(a) monocarpic plants
(b) polycarpic plants
(c) vegetative plants
(d) reproductive plants

Answer Answer:
(a) Monocarpic plants are the plants in which flowers and fruits are formed only once after vegetative growth of several years e.g., some bamboos, Agave, etc.

Q.21. Select the mismatched pair.
(a) Microsporangium — Pollen sac
(b) Megasporangium — Nucellus
(c) Pollen grain — Male gamete
(d) Embryo sac — Female gametophyte

Answer Answer:

Q.22. A typical angiospermous ovule is attached to the placenta by means of a stalk called X. Body of the ovule fuses with X in the region called Y. Identify X and Y.
X | Y
(a) Funicle Hilum
(b) Hilum Funicle
(c) Funicle Micropyle
(d) Hilum Chalaza

Answer Answer:

Q.23. Which of the following options is correct?
(a) Transfer of pollen grains from the anther to the stigma of the same flower – Autogamy.
(b) Transfer of pollen grains from the anther of one flower to the stigma of another flower of same plant – Geitonogamy.
(c) Transfer of pollen grains from the anther to the stigma of a genetically different plant – Xenogamy.
(d) All of these

Answer Answer:

Q.24. Which of the following is not a water pollinated plant?
(a) Zostera
(b) Vallisneria
(c) Hydrilla
(d) Cannabis

Answer Answer:

Q.25. Identify the parts labelled A, B, C and D in the given figure and select the correct option.

(a) Synergids, Antipodals, Egg, Filiform apparatus
(b) Antipodals, Synergids, Egg, Filiform apparatus
(c) Antipodals, Synergids, Filiform, Egg appartus
(d) Polar nuclei, Antipodals, Filiform, Egg appartus

Answer Answer:

Q.26. Growth of pollen tube towards embryo sac is
(a) chemotropic
(b) thigmotaxis
(c) geotropic
(d) none of these

Answer Answer:
(a) The pollen tube eats its way through the solid part of the stigma and style by secreting pectinases and hydrolytic enzymes. Pollen tube travels intercellularly and chemotropically along the concentration gradient of calcium – boron -inositol sugar complex.

Q.27. The part of gynoecium that determines the complatible nature of pollen is
(a) stigma
(b) style
(c) ovary
(d) synergids

Answer Answer:
(a) Stigma is the terminal receptive part of the pistil which functions as landing platform for the pollen grains. It also determines the compatibility of the pollen grains.

Q.28. The innermost layer of anther is tapetum whose function is
(a) dehiscence
(b) mechanical
(c) nutrition
(d) protection

Answer Answer:
(c) The tapetal layer is of great physiological significance as all the food material entering into the sporogenous tissue diffuses through this layer. Ultimately, the cells of tapetal layer disorganise. Thus, tapetum makes a nutritive layer for the developing microspores.

Q.29. The female gametophyte of a typical dicot at the time of fertilization is
(a) 8-celled
(b) 7-celled
(d) 6-celled
(d) 5-celled

Answer Answer:
(b) The typical and the most common type of embryo sac, found in 80% flowering plants is called Polygonum type of embryosac. It contains 8 nuclei but 7 cells – 3 micropylar, 3 chalazal and one central. It is formed by one meiosis and three mitosis.

Q.30. One of the most resistant biological material present in the exine of pollen grain is
(a) pectocellulose
(b) sporopollenin
(c) suberin
(d) cellulose

Answer Answer:
(b) Outer layer (exine) of pollen grain is made of a highly resistant substance called sporopollenin (Zelisch, 1932). Sporopollenin is not degraded by any enzyme. It is not affected by high temperature, strong acid or strong alkali. Because of sporopollenin, pollen grains are well preserved as fossils.

Q.31. What is the function of germ pore?
(a) Emergence of radicle
(b) Absorption of water for seed germination
(c) Initiation of pollen tube
(d) All of these

Answer Answer:

Q.32. How many meiotic divisions are required for the formation of 100 functional megaspores?
(a) 100
(b) 50
(c) 25
(d) 26

Answer Answer:
(a) Megaspore mother cell (MMC) is the sporogenous cell that divides to give 4 haploid megaspores. Out of these 4 megaspores, only one is functional and other three degenerate. Hence 100 meiotic divisions are required for the formation of 100 functional megaspores.

Q.33. Study of pollen grains is called
(a) micrology
(b) anthology
(c) palynology
(d) pomology

Answer Answer:

Q.34. Which of these is a condition that makes flowers invariably autogamous?
(a) Dioecy
(b) Self incompatibilty
(c) Cleistogamy
(d) Xenogamy

Answer Answer:
(c) Autogamy is possible only when anther and stigma are close together and there is synchrony in pollen release and stigma receptivity. As in case of cleistogamous flowers, the flowers remain closed so that anthers and stigmas are never exposed. The flowers undergo only self pollination. No external pollinating agency is required.

Q.35. An embryo may sometimes develop from any cell of embryo sac other than egg. It is termed as
(a) apospory
(b) apogamy
(c) parthenogenesis
(d) parthenocarpy

Answer Answer:
(b) Apogamy is the reproduction without the fusion of gametes, and usually without meiosis. The term may include any form of vegetative reproduction. The production of a diploid gametophyte from the sporophyte due to the absence of meiosis is known as apospory. Parthenogenesis is the development of an unfertilized egg into a complete individual without fertilization. Production and development of seedless fruits is called parthenocarpy.

Q.36. Endosperm is completely consumed by the developing embryo in
(a) pea and groundnut
(b) maize and castor
(c) castor and groundnut
(d) maize and pea

Answer Answer:
(a) Endosperm represents the food storing tissue of a seed. It is produced as a result of double fertilization in angiosperms. In most monocots and some dicot seeds, the food reserve remains in the endosperm. They are called endospermic or albuminous seeds, e.g., cereals, castor, coconut, rubber. However, in the majority of dicot seeds (e.g., pea, gram, bean, mustard, groundnut) and some monocot seeds (e.g., orchids, Sagittaria), the endosperm is consumed during seed development and the food is stored in cotyledons and other regions. They are called nonendospermic or exalbuminous seeds.

Q.37. The portion of embryonal axis between plumule (future shoot) and cotyledons is called
(a) hypocotyl
(b) epicotyl
(c) coleohize
(d) coleoptile

Answer Answer:
(b) Part of embryo axis between the plumule and cotyledonary node is epicotyl (above the level of cotyledons) while the part between radicle and cotyledonary node is called hypocotyl (below the level of cotyledons).

Q.38. Stigma of a flower is removed before pollination. The flower will
(a) Form fruit normally
(b) Not form fruit
(c) Form deformed fruit
(d) Form fruit smaller than normal size

Answer Answer:
(b) Pollination will not occur

Q.39. In a pea flower, all petals are removed before pollination. The flower will
(a) Form fruit normally
(b) Not form fruit
(c) Form smaller pod
(d) Form deformed pod

Answer Answer:
(b) There will not be insect pollination

Q.40. A drop of glue is placed on the stigma of a flower before pollination. The flower will
(a) Not form fruit
(b) Form normal fruit
(c) Form sticky fruit
(d) Form fruit filled with glue

Answer Answer:
(a) Germination of pollens will not occur in ovule.

Q.41. An apomictic seed contains an embryo that is
(a) produced when two sperm fertilize one egg.
(b) developed from one egg alone.
(c) the result of parental self-fertilization
(d) genetically identical to its parent.

Answer Answer:

Q.42. The embryo is carefully taken out of pea seed and sown in the soil and watered normally. New plant will
(a) Be healthier
(b) Be weaker
(c) Not be formed
(d) Be formed normally

Answer Answer:
(c) Embryo can not grow without food stored in cotyledons.

Q.43. Angiospermic plant has chromosome number of 24. The number of chromosomes in pollens will be
(a) 6
(b) 12
(c) 24
(d) 48

Answer Answer:
(b) Pollens are formed by meiosis.

Q.44. What is the fate of the seven cells of the embryo sac ?
(a) All but one disintegrate upon fertilization.
(b) Two become fertilized; the others disintegrate.
(c) Two become fertilized; the others fuse to form endosperm.
(d) All are involved in nuclear fusion events.

Answer Answer:

Q.45. A close relation between flower and pollinating agent is best exhibited by :
(a) Cocos
(b) Salvia
(c) Yucca
(d) Avena

Answer Answer:
(c) Obligate symbiotic relationship is present between Yucca flowers and moth, Tageticula.

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