12th Bio_Sexual Reproduction in Flowering Plants_Avanti Module

B24 – Sexual Reproduction in Flowering Plants 21 Fourth Edition B24. Sexual Reproduction in Flowering Plants TABLE OF CONTENTS B24. Sexual Reproduction in Flowering Plants 21 Points to Remember..................................................................................................................................................................................22 B24.1 Sexual Reproduction in Plants...............................................................................................................................................24 B24.2 Pollination: Types and Agencies ...........................................................................................................................................31 B24.3 Double fertilization: Process and Significance...............................................................................................................38 Answer Key....................................................................................................................................................................................................46

B24 – Sexual Reproduction in Flowering Plants 22 Points to Remember  Flowers are the site of sexual reproduction in flowering plants. These contain male stamens and female carpels or pistils. A typical flower consists of four whorls of floral appendages, attached on the receptacle i.e. calyx, corolla, androecium (male part), gynoecium (female part).  Male gametophyte consists of a stamen, microsporangium and a pollen grain. Out of which stamen represents a male reproductive part or male unit of a flower.  A typical stamen has two main parts i.e. an anther and a long slender filament. The anther is a bilobed structure with each lobe having two theca. It has four a sided structure consisting of microsporangia which develops and becomes pollen sacs that contain pollen grains.  The formation of microspores from a pollen mother cell through meiosis is called microsporogenesis. Pollen grains are released by dehiscence of an anther. Pollen grains have the following characteristic features: I. Spherical, about 25 – 50 micrometer in diameter. II. Outer hard layer exine is made up of sporopollenin (no enzyme can degrade it as so far known). III. Germ pore is present on exine, where sporopollenin is not present. IV. Intine (inner layer) is made – up of cellulose and pectin. V. Vegetative cell in pollen grain is bigger, which contains food reserves. VI. Generative cell is small, which floats on the cytoplasm of vegetative cell. VII. In about 60% of angiosperms, pollen grains shed at 2 – celled stage.  Pistil is the female reproductive unit of a flower. Pistil may be syncarpous (more than one pistil are fused together) e.g. in Solanum, Papaver etc. may also be apocarpous (pistils remain free) e.g. in rose etc. The main parts of pistil are: I. Stigma II. Style III. Ovary  Stigma is meant to receive pollen grains, style is the slender part below the stigma while, the basal swollen part of style is called ovary. The formation of megaspores from megaspore mother cell is called megasporogenesis.  Ovule is attached to the placenta by a stalk called funicle. Hilum is a junction between ovule and funicle. Each ovule contains one – two protective envelops called integuments. Micropyle is present at the tip while chalaza is opposite to the micropylar end representing the basal part of nucleus. Nucellus have food reserves. Embryo sac or female gametophyte is located in the nucellus.  Only one of the megaspore is functional which develops into female gametophyte or embryo sac. This is called monosporic development while the other three degenerate in most of the angiosperms.  Embryo sac forms when the nucleus divides mitotically to form two nuclei, which move to the opposite poles and form 2 – nucleate embryo sac, which then results into the formation of 4 – nucleate and later 8 – nucleate stages due to nuclear division.  Out of eight nuclei, six are surrounded by the cell walls and organized into cells and the remaining two called polar nuclei are situated below the egg apparatus which consists of two naked cells adjoining egg cells called synergids and one largest egg cell or ovum.  Three remaining cells are present i.e., antipodal cells at the chalazal end which are surrounded by cytoplasm and cellular wall.  As 8 nuclei contribute in the formation of gametophyte so, the above mentioned method of formation of female gametophyte is called normal 8 – nucleate type which is very common among angiosperms. Points

B24 – Sexual Reproduction in Flowering Plants 23  Pollination is the transfer of pollen grains from anther and their deposition over stigma of the pistil. It is of the following three major types: I. Autogamy (Self – pollination) - The transfer is between same flower e.g. pea, rice, wheat, etc. II. Geitonogamy- The transfer is between two different flowers of same plant e.g. Cucurbita. III. Xenogamy/ Allogamy (Cross – pollination) - The transfer is between two flower of two different plants e.g. papaya.  Two categories of agents are mainly responsible for the transfer of pollen grains i.e. abiotic agents (wind and water) and biotic agents (animals like reptiles, birds, insects, mammals, etc.).  Pollen – pistil interaction is an essential step in fertilization of angiosperms because it determines the compatibility and incompatibility. It generally includes the events from the deposition of pollen on the stigma till the pollen tube enters ovule through micropyle and enters one of the synergids through the filiform apparatus.  This pollen – pistil interaction comprises of three stages: I. Recognition of compatible pollen II. Growth of a pollen tube III. Entry of pollen tube into the ovule  Artificial hybridization is the phenomenon in which desired pollen grains are used for pollination and the stigma is prevented from contamination with unwanted pollen. This is done by emasculation in which anthers are removed from the flower bud before their dehiscence using a pair of forceps and by bagging in which emasculated flower is covered with a bag to prevent the contamination of stigma by unwanted flowers.  The pollen tube releases two male gametes into a cytoplasm of a synergid out of which one male gamete fuses with the egg cell to form triploid PEN (Primary Endosperm Nucleus). This process is called triple fusion.  As two fusion i.e. syngamy and triple fusion occur in an embryo sac. The phenomenon is called double fertilization.  After double fertilization, following changes takes place like development of an endosperm and an embryo, maturation of ovules into seed and ovary into fruit  Endosperm development takes place by three methods i.e. nuclear type, cellular type and helobial type. Out of which nuclear type is the most common one in which the PEN undergoes repeated mitotic division without cytokinesis. At this stage, endosperm is called free endosperm nucleus.  Development of an embryo takes place at the micropylar end of the embryo sac where zygote is situated. Embryos are of two types i.e. dicot embryo which consists of two cotyledons and the embryonal axis between them e.g. apple, mango, etc. and a monocot embryo which consists of only one cotyledon (called scutellum) e.g. rice, maize etc.  Seed or ovule is the final product of sexual reproduction which consist of a seed coat, cotyledons and an embryo axis.  Non – albuminous seeds have no residual endosperm as it is completely consumed in the embryo development e.g. pea, groundnut etc. while, albuminous seeds retain a part of an endosperm as it is completely consumed up during an embryo development e.g. wheat, maize etc.  A fruit is formed as a result of cell division and differentiation of the ovary. The wall of the ovary develops into the wall of a fruit called pericarp which may be fleshy (e.g. tomato, guava cucumber, etc.) or may be leathery or dry (e.g. pea, bean, mustard, etc.). Pericarp protects the seed and helps in the dispersal of seed  Fruits are of two main types i.e. true fruits which derived from an ovary of a flower not associated with any non – carpillary part e.g. mango, tomato etc. In this, other floral parts degenerate and fall off. And the other are false fruits which are derived from an ovary along with other floral part. In these thalamus also contribute in fruit formation e.g. strawberry, apple, etc.  Apomixis is the special method to produce seeds without fertilization e.g. grasses. It is useful in the hybrid industry.  Polyembryony is the condition in which more than one embryo are present in a seed. E.g. in citrus, mango varieties etc. Points

B24 – Sexual Reproduction in Flowering Plants 24 B24.1 Sexual Reproduction in Plants CONCEPTS 1. Sexual reproduction and the organelles involved in sexual reproduction. 2. Aesthetic uses of the flower and also the use of the flower in sexual reproduction. 3. Major function of anther in sexual reproduction. 4. Parts of the anther wall. 5. Structure and function of the epidermis, endothecium, middle layer and tapetum. 6. Position of microsporangium and the processes involved in microsporogenesis. 7. Structure of the pollen grain. 8. Process of male gametophyte development. 9. Process taking place inside the pollen grains. 10. Structure of an anatropous ovule and the processes taking place inside an ovule. 11. Structure of the body, nucellus and chalaza. 12. Structure of integuments and embryo sac. 13. Processes taking place inside the female gametophyte leading to the formation of the embryo sac. PRE-READING Chapter in HSC Section in HSC Chapter in NCERT Section in NCERT 8 8.2 2 2.1, 2.2 Category REQUIRED PRE-READING EXERCISE LEVEL 1 Q1. Flower is a B) modified cone. D) modified branch system. A) modified spike. C) modified reproductive shoot. Q2. Specialized, condensed shoot meant for sexual reproduction is _____________. A) inflorescence B) ovule C) flower D) pollen grain Q3. A characteristic of angiosperms is ____________. A) flower B) root C) seed D) both B & C Q4. Viability of pollen is controlled by ____________. B) humidity D) both (B) and (C) A) light C) temperature Q5. Pollen should reach on _________ for further development. A) carpel B) gynoecium C) stigma D) pistil Q6. Bronchitis and asthma can be caused by ___________. A) pollen grains B) rain C) sun D) humidity B24.1

B24 – Sexual Reproduction in Flowering Plants 25 Q7. In cryopreservation pollen grains are kept at ___________. A) 90°������ B) −90°������ C) −196°������ D) −200°������ D) four Q8. Nuclei present in mature male gametophyte of angiosperms is __________. A) one B) two C) three LEVEL 2 Q9. Anthesis refers to B) chasmogamy. A) opening of flowers. D) arrangement of filaments. C) removal of anthers. Q10. Most famous plant causing pollen allergy is ______________. A) parthenium B) rose C) mango D) neem IN CLASS EXERCISE LEVEL 1 Q1. The genesious part of stamen is _____________. A) filament B) connective C) anther D) stigma Q2. Anther is connected to filament by ____________. A) connective B) placenta C) funicle D) style Q3. Pollen grains producing structure is called ___________. B) microsporangium A) megasporangium D) nucellus C) male gametophyte Q4. At the time of pollination, angiospermic pollen grain is mostly A) one celled structure. B) two celled structure. C) three celled structure. D) four celled structure. Q5. The areas on the surface of the pollen grains where exine is very thin or absent is _____________. A) micropyle B) pollen chamber C) locule D) germ pore Q6. The direction of micropyle in anatropous ovule is ______________. A) right B) left C) upward D) downward Q7. Egg apparatus is made up of B) antipodals and synergids. A) secondary nucleus and antipodals. D) egg and synergids. C) synergids and polar nucleus. Q8. Ovule is attached to placenta by ____________. A) pedicel B) style C) petiole D) funicle Q9. Pollen tube of male gametophyte is produced from ____________. A) vegetative cell B) prothalial cell C) generative cell D) endothecium Q10. Which of the following statements is correct for the pollen tube? A) It shows chemotactic movement. B) It shows only tip growth. C) It is composed of three non-cellular zones. D) It shows radial cytoplasmic streaming. B24.1

B24 – Sexual Reproduction in Flowering Plants 26 Q11. Which one of the following statements is incorrect? A) When pollen is shed at two-celled stage, double fertilization does not take place. B) Vegetative cell is larger than generative cell. C) Pollen grains in some plants remain viable for months. D) Intine is made up of cellulose and pectin. Q12. Which one of the following statements is correct? B) Endothecium produces the microspores. D) Hard outer layer of pollen is called intine. A) Sporogenous tissue is haploid. C) Tapetum nourishes the developing pollen. Q13. Match the parts of gynoecium given in column I with their definition given in column II. Choose the correct combination from the options given below. Column -I Column –II a) Funicle i. Mass of cells within ovule with more food b) Hilum ii. Basal part of ovule c) Integument iii. One or 2 protective layers of ovule d) Chalaza iv. Region where body of ovule fuses with funicle e) Nucellus v. Stalk of ovule A) a – i; b – ii; c – iii; d – iv; e – v B) a – v; b – iv; c – iii; d – ii; e – i C) a – iv; b – ii; c – i; d – iii; e – v D) a – i; b – iii; c – v; d – ii; e – iv Q14. Which of the following is a mismatched pair? B) Megasporangium – Ovule D) Megasporophyll – Filament A) Microsporangium – Pollen sac C) Microsporophyll – Stamen Q15. The given diagram refers to a ������. ������. of another. Identify ������ to ������ respectively. A) Sporogenous tissue, tapetum, epidermis, middle layer, endothecium B) Sporogenous tissue, epidermis, tapetum, middle layer, endothecium C) Sporogenous tissue, epidermis, middle layer, tapetum, endothecium D) Sporogenous tissue, tapetum, middle layer, epidermis, endothecium Q16. The given figure shows a typical stamen (������) and three dimensional cut section of an anther. Identify ������ to ������ respectively marked in the figure (������ & ������) A) Anther, petiole, pollen sac and megaspore B) Anther, petiole, megasporangium and pollen grains C) Anther, pedicel, megasporangium and pollen grains D) Anther, filament, pollen sac and pollen grains B24.1

B24 – Sexual Reproduction in Flowering Plants 27 Q17. Identify ������, ������, ������, ������ and ������ structures marked in the given figure of a mature embryo sac. A) Antipodal cells, Central cell, Polar nuclei, Synergids, Acrosome. B) Antipodal cells, Central cell, Polar nuclei, Synergids, Filiform apparatus. C) Synergids, Central cell, Polar nuclei, Antipodal cells, Filiform apparatus. D) Synergids, Megaspore mother cell, Polar nuclei, Synergids, Filiform apparatus. Q18. In the given figure of pollen grain tetrad, identify the parts marked as ������, ������, ������, ������ and ������. A) Germ pore, Generative cell, Intine, Exine, Vegetative cell. B) Germ pore, Generative cell, Exine, Intine, Vegetative cell. C) Intine, Exine, Germ pore, Generative cell, Vegetative cell. D) Exine, Intine, Vegetative cell, Germ pore, Generative cell. Q19. One of the most resistant known biological material is ___________. A) lignin B) hemicellulose C) sporopollenin D) lignocellulose Q20. In a fertilized ovule, ������, 2������ and 3������ conditions occur respectively in A) antipodal, egg and endosperm. B) egg, nucellus and endosperm. C) endosperm, nucellus and egg. D) antipodals, synergids and integuments. Q21. Product of sexual reproduction generally generates B) new genetic combination leading to variation. D) longer viability of seeds. A) prolonged dormancy. C) large biomass. Q22. Which of the following processes is necessary for the complete development of male gametophyte? A) One meiotic cell division and two mitotic cell divisions. B) One meiotic cell division and one mitotic cell division. C) Two meiotic cell divisions and one mitotic cell division. D) Two mitotic cell divisions. Q23. How many meiotic divisions are required to produce 1000 pollen grains? A) 200 B) 250 C) 500 D) 1000 LEVEL 2 Q24. Funicle is B) base of ovule. D) stalk of ovule. A) apex of ovule. C) covering of ovule. Q25. Fully developed male gametophyte in angiosperm is derived from a PMC by A) one meiosis. B) one meiosis and one mitosis. C) one meiosis and two mitosis. D) two meiosis and two mitosis. B24.1

B24 – Sexual Reproduction in Flowering Plants 28 HOMEWORK LEVEL 1 Q1. Flower is considered to be a modified shoot because A) essential organs are present in the single flower. B) thalamus becomes elongated and show distinct nodes and internodes. C) it is highly branched. D) it produces smaller and larger floral whorls. Q2. Sexual reproduction leads to _______________. A) parthenocarpy B) recombination C) apomixis D) parthenogenesis Q3. A flower is said to be complete when it has B) androecium and gynoecium only. D) all the four floral whorls. A) calyx and corolla only. C) calyx, corolla and androecium. Q4. Perianth is the term used when A) calyx and corolla are different. B) calyx and corolla are undifferentiated. C) androecium and corolla are similar. D) androecium and gynoecium are similar. Q5. Most common type of anther in angiosperm is _____________. A) monothecous B) dithecous C) trithecous D) tetrathecous Q6. Dithecous anther is _____________. A) unilocular B) bilocular C) trilocular D) tetralocular Q7. In the anther wall A) endothecium lies inner to the tapetum. B) middle layer lies next to the epidermis. C) middle layer lies between endothecium and tapetum. D) tapetum lies next to the epidermis. Q8. A double layered wall of pollen grain is called _______________. A) sporoderm B) endothecium C) mesocarp D) epiderm Q9. In pollen grain layer nucleus is _______________. B) generative nucleus D) vegetative nucleus A) tube nucleus C) prothallial nucleus Q10. Development of male gametophyte is ______________. B) endosporic D) megasporic A) asporic C) exosporic Q11. Dicot pollens are mostly ______________. A) uniporate B) biporate C) triporate D) teraporate Q12. Ovule is called B) forerunner of the fruit. D) forerunner of the ovary. A) forerunner of the seed. C) forerunner of the plant. Q13. The basal bulged part of the pistil is ___________. A) ovule B) style C) ovary D) anther B24.1

B24 – Sexual Reproduction in Flowering Plants 29 Q14. The non sex cells in male and female gametophytes are B) synergids and egg cell. A) vegetative cell and egg cell. D) egg cell and secondary nucleus. C) tube cell, antipodals and synergid. Q15. The central mass of parenchymatous cells in ovule is celled ______________. A) pericarp B) nucellus C) mesocarp D) chalaza Q16. The result of fusion of two haploid nuclei i.e. one from micropylar end and another from chalazal end is A) vegetative nucleus. B) definitive nucleus. C) generative nucleus. D) somatic nucleus. Q17. Megasporangium is equivalent to? A) Fruit B) Nucellus C) Ovule D) Embryo sac Q18. In anatropous ovule, the micropyle is B) at 30° with funicle. A) side by side with funicle. D) in straight line with funicle. C) at right angles with funicle. Q19. Formation of embryo sac directly from megaspore mother cell in angiosperms is called _____________. A) apogamy B) diplospory C) agamospermy D) apospory Q20. Embryo sac is embedded in nucellus at which end of the ovule? A) Micropylar B) Chalazal C) Funicular D) In the centre Q21. Which of the following statements about sporopollenin is incorrect? A) Exine is made up of sporopollenin. B) Sporopollenin is one of the most resistant organic materials. C) Exine has apertures called germ pores where sporopollenin is present. D) Sporopollenin can withstand high temperatures and strong acids. Q22. Which one of the following events takes place after double fertilization? A) The pollen grain germinates on the stigma. B) The pollen tubes enter the embryo sac. C) Two male gametes are discharged into the embryo sac. D) The PEN (Primary Endosperm Nucleus) develops into endosperm. Q23. Which of the following statement is correct? A) Sporopollenin can withstand high temperatures but not strong acids. B) Sporopollenin can be degraded by enzymes. C) Sporopollenin is made up of inorganic materials. D) Sporopollenin can withstand high temperature as well as strong acids and alkalis. Q24. Match the items given in column-I with those given in column-II and choose the correct option given below. Column-I Column-II a) Tapetum i. Irregular in shape with abundant food reserve b) Exine ii. Acts as nutritive layer c) Pollen kit iii. Thick, rigid protective layer d) Vegetative cell iv. Involve in the formation of microspores e) Sporogenous tissue v. Oily and sticky layer, help in pollination. A) a – ii; b – iii; c – v; d – iv; e – i B) a – i; b – iii; c – ii; d – iv; e – v C) a – ii; b – iii; c – i; d – iv; e – v D) a – ii; b – iv; c – v; d – i; e – iii B24.1

B24 – Sexual Reproduction in Flowering Plants 30 Q25. Male gametophyte in angiosperms produces B) single sperm and a vegetative cell. D) three sperms. A) two sperms and a vegetative cell. C) single sperm and two vegetative cells. Q26. Consider the following statements and choose the correct option. I. Ovule is attached to the placenta by means of a stalk called filament. II. Ovule fuses with the stalk in the region called hilum. III. The two protective envelopes of the ovule are called integuments. IV. The small opening in the tip of ovule is called germ pore. A) I and IV B) I and III C) II and IV D) II and III Q27. Which is not properly matched. A) Exine of pollen grain – Sporopollenin B) Tapetum – Ubisch bodies C) Male gametophyte of angiosperms – No prothalial cells D) Most common type of ovule – Orthotropous Q28. If there are 1280 microspores in a tetralocular anther, how many microspore mother cells will be there in its each pollen chamber? A) 80 B) 160 C) 240 D) 1280 Q29. How many chromosomes are present in each of the following with respect to maize plants respectively? I. Leaf epidermal cell II. Antipodal cell III. Endosperm cell IV. Generative cell V. Egg cell VI. Megaspore A) 10, 20, 10, 10, 10, 20, 30 B) 20, 10, 30, 10, 10, 10,20 C) 20, 10, 10, 10, 20, 30, 10 D) 30, 10, 20, 10, 20, 10, 10 Q30. An angiospermic male plant with 24 chromosomes in its pollen mother cells is crossed with a female plant having 24 chromosomes in its root cells. What would be the chromosome number of the embryo and endosperm respectively after the cross? A) 24 and 48 B) 24 and 24 C) 48 and 72 D) 24 and 36 LEVEL 2 Q31. In mature anther, epidermis is followed by ______________. A) exodermis B) endothecium C) middle layer D) tapetum Q32. Which part of the anther produces both enzymes and hormones? A) Tapetum B) Endothecium C) Endodermis D) Epidermis Q33. Which one of the following statements is correct? B) Endothecium produces the microscopes. A) Sporogenous tissue is haploid. D) Hard outer layer of pollen is called intine. C) Tapetum nourishes the developing pollen. Q34. How many pollen mother cells will form 1000 pollen grains? A) 200 B) 250 C) 300 D) 100 B24.1

B24 – Sexual Reproduction in Flowering Plants 31 B24.2 Pollination: Types and Agencies CONCEPTS 1. Pollination and basic structures involved in pollination. 2. 2 types of pollination. 3. Autogamy and the basic process involved in it. 4. Geitonogamy and the basic processes involved in it. 5. Advantages and disadvantages of self-pollination. 6. Self-pollination takes place in homogamous plants. 7. Cross pollination between xenogamous flowers is. 8. Anemophily, hydrophily, hypohydrophily, epihydrophily, entomophily, ornithophily, chiropterophily. 9. Pollen pistil interaction. 10. Importance in fertilization. 11. Transportation of organelles by the pollen tube. 12. Process of pollen tube entering the ovule. PRE-READING Category Chapter in HSC Section in HSC Chapter in NCERT Section in NCERT REQUIRED 8 8.3 2 2.2.3 PRE-READING EXERCISE LEVEL 1 Q1. Pollination is shown by _______________. A) algae B) fungi C) bryophytes D) angiosperms D) allogamy Q2. In angiosperm the first step towards sexual reproduction is __________________. D) bracts A) pollination B) fertilization C) fruit formation D) seed formation Q3. If pollination takes place between same species it is _______________. A) autogamy B) geitonogamy C) xenogamy Q4. Naturally pollination will takes place between ______________. B) different species D) same genera A) same species C) different genera Q5. Plants showing sterility can be propagated by ______________. B) stem cutting A) root cutting D) sexual method C) both (A) and (B) Q6. Fruits formed without fertilization are known as ______________. A) epicarpic B) mesocarpic C) endocarpic D) parthenocarpic Q7. In Bougainvillea _________ is colourful parts to perform entomophily A) corolla B) calyx C) leaf B24.2

B24 – Sexual Reproduction in Flowering Plants 32 LEVEL 2 Q8. In Salvia, _________ lobe of anther produces pollen grains. A) upper B) lower C) middle D) basal Q9. Seedless variety can be propagated by B) tissue culture method. A) vegetative method. D) flowers. C) both (A) and (B). Q10. Cross pollination offers certain advantages as well as disadvantages to plants. Which one of the following statement is not true about cross pollination? A) Can fail to take place due to distance barrier. B) Is less economic because plants have to produce large number of pollen grains. C) Often gives high yield of a crop. D) Takes place only in monoecious (unisexual) flowers. IN CLASS EXERCISE LEVEL 1 Q1. Unisexuality of flowers prevents B) both geitonogamy and xenogamy. A) autogamy but not geitonogamy. D) autogamy and geitonogamy. C) geitonogamy but not xenogamy. Q2. Wind pollination is common in _____________. A) lilies B) grasses C) orchids D) legumes Q3. Long, ribbon – like pollen grains are seen in some B) wind – pollinated grasses. A) aquatic plants. D) bird – pollinated flowers. C) gymnosperms. Q4. When pollen is transferred from anther of a flower to stigma of another flower of the same plant, it is referred to as _____________. A) allogamy B) xenogamy C) geitonogamy D) autogamy Q5. If an angiospermic male plant is diploid and female plant tetraploid, endosperm will be ______________. A) haploid B) triploid C) tetraploid D) pentaploid Q6. Unwettable floral parts and pollen grains are found in _________ flowers. A) anemophilous B) entamophilous C) hydrophilous D) zoophilous Q7. Which of the following statements is incorrect about emasculation? A) During emasculation process, stigma is removed. B) Emasculated flowers are bagged in order to prevents self-pollination. C) Emasculation is the removal of stamens before the maturation of selected bisexual flowers. D) It is one of the steps for artificial hybridization. Q8. Which one of the following statements is correct? A) Geitonogamy involves the pollen and stigma of flowers of different plants. B) Cleistogamous flowers are always autogamous. C) Xenogamy occurs only by wind pollination. D) Chasmogamous flowers do not open at all. B24.2

B24 – Sexual Reproduction in Flowering Plants 33 Q9. Which of the following statement(s) is/are correct about self-incompatibility? I. It is a device to prevent inbreeding. II. It provides a biochemical block to self-fertilization. III. It ensures cross-fertilization. IV. It is governed by pollen-pistil interaction. V. It is governed by series of multiple alleles. VI. It prevents self-pollen (from the same flower of other flowers of the same plant) from fertilizing the ovules by inhibiting pollen germination of pollen tube growth in the pistil. A) (I), (II) and (III) B) (I), (IV) and (V) C) All of the above D) None of the above Q10. Match the abiotic agent of cross pollination given in column-I with their feature given in column-II and select the correct answer using the codes given below. Column-I Column-II a) Zoophily i. Pollination by birds b) Ornithophily ii. Pollination by insects c) Entomophily iii. Pollination by bats d) Chiropterophily iv. Pollination by animals A) a – iii; b – ii; c – i; d – iv B) a – i; b – ii; c – iii; d – iv C) a – iv; b – i; c – ii; d – iii D) a – iv; b – ii; c – i; d – iii Q11. Which of the following figures, showing the types of gynoecium, is associated with wind pollination? A) B) C) D) Q12. The given diagram shows 2 plants of the same species. Identify the type of pollination indicated as ������1, ������2 and ������3. A) ������1 – Allogamy, ������2 – Chasmogamy, ������3 – Cleistogamy. B) ������1 – Allogamy, ������2 – Xenogamy, ������3 – Geitonogamy. C) ������1 – Allogamy, ������2 – Geitonogamy, ������3 – Xenogamy. D) ������1 – Geitonogamy, ������2 – Allogamy, ������3 – Autogamy. Q13. Consider the following statements with respect to the flowering plants and choose the correct option. I. Pollen grains represent the male gametes. II. Functional megaspore develops into embryo sac that represents the female gamete. III. Transfer of pollen grains from anther to stigma of different plant is known as xenogamy. IV. Transfer of pollen grains from anther to stigma of another flower of the same plant is known as geitonogamy. A) I and II B) I and III C) I and IV D) III and IV B24.2

B24 – Sexual Reproduction in Flowering Plants 34 Q14. Which is not a correct explanation of cross pollination? A) Pollen grains of male flowers are transferred to stigma of female flowers. B) Pollen gains are transferred from one flower to another flower of another plant of the same species. C) Pollen grains are transferred from one flower to another flower situated on the same species. D) Pollen grains of one flower are transferred to the stigma of the same flower. Q15. Match the columns and find the correct combination. Column-I Column-II a) Pisum sativum i. Chasmogamy and cleistogamy b) Commelina ii. Self pollination c) Water Hyacinth iii. Cross pollination and self sterility d) Abutilon iv. Protogyny and entomophily e) Solanum v. Entomophily and anemophily A) a – ii; b – i; c – v; d – iii; e – iv B) a – v; b – i; c – ii; d – iii; e – iv C) a – ii; b – v; c – iv; d – iii; e – i D) a – ii; b – v; c – i; d – iii; e – iv LEVEL 2 Q16. Wind pollinated pollens are A) small, brightly coloured, producing large number of pollen grains. B) small, producing large number of dry pollen grains. C) large producing abundant nectar and pollen. D) small, producing nectar and dry pollen. Q17. Below are given a few evolutionary trends relating to the flower structure of land plants. Mark the incorrect trend. A) Wind pollination → Insect pollination B) Open ovules → Ovules enclosed in ovary C) Indirect pollination → Direct pollination D) Single seeded fruit → Multiple seeded fruit HOMEWORK LEVEL 1 Q1. In autogamy the flowers are ____________. A) unisexual B) bisexual C) monoecious D) dioecious Q2. _________ type of pollination helps in evolution B) Xenogamy D) insect D) Geitonogamy D) ������ A) Autogamy C) Allogamy Q3. Bat pollination is referred as _____________. B) zoophily D) chiropterophily A) entomophily C) ornithophily Q4. The agent of Anemophily is _____________. A) animal B) wind C) water Q5. Secondary nucleus present in middle of embryo sac is __________. A) 2������ B) 4������ C) 3������ B24.2

B24 – Sexual Reproduction in Flowering Plants 35 Q6. In angiosperms how many male gametes are produced by one meiosis in one pollen mother cell (PMC) is _________. A) 4 B) 8 C) 1 D) 2 Q7. Which one of the following is surrounded by a callose wall? B) Pollen grain D) Male gamete A) Egg C) Microspore mother cell Q8. Long silky hair coming out of the cob of maize are B) meant for attracting insects. D) long styles and stigma. A) meant for fruit dispersal. C) meant for protecting seeds. Q9. The term used when anthers and stigmas of intersexual or perfect flowers ripen before the opening of buds as in wheat and pea is ___________. A) bud pollination B) immature pollination C) cross pollination D) cleistogamy Q10. Pollination occurs when a pollen grain A) releases its sperm nuclei. B) lands on stigma. C) matures and has 3 nuclei. D) releases its sperm nuclei and fertilize the egg and polar nuclei. Q11. Pollination is characteristic of B) Pteridophytes and Angiosperms. D) Angiosperms and Fungi. A) Bryophytes and Angiosperms. C) Angiosperms and Gymnosperms. Q12. Progeny produced as a result of cross pollination A) shows high degree of variability and is evolutionary important. B) is sterile. C) has recessive characters. D) is homozygous with phenotypic uniformity. Q13. Emasculation is A) pollination between flowers of different plants. B) pollination between flowers of the same plants. C) removal of the anthers from the flower bud. D) artificial pollination before opening of flower. Q14. Allogamy is best favoured by ___________. B) homogamy D) cleistogamy A) dicliny C) bud pollination Q15. In Salvia and Ficus pollination takes place by ____________. B) insects A) birds D) water C) air Q16. Pollen grains of a flower fall on the stigma of another flower of the same plant. The phenomenon is A) genetically self-pollination. B) genetically self-pollination and ecologically cross pollination. C) ecologically cross pollination. D) genetically cross pollination and ecologically self-pollination. B24.2

B24 – Sexual Reproduction in Flowering Plants 36 Q17. Autogamy is A) transfer of pollen from one flower to another flower of the same plant. B) transfer of pollen from anther to the stigma of the same flower. C) presence of male and female sex organs in the same flower. D) germination of pollen within the anther. Q18. Papaya is a dioecious plant. This condition prevents B) only autogamy. D) geitonogamy. A) both autogamy and geitonogamy. C) only xenogamy. Q19. Select the plants pollinated by water. B) II and V D) II, III, IV I. Water Hyacinth II. Zostera III. Amorphophallus IV. Vallisneria V. Yucca A) I, IV and V C) II and IV Q20. Wind pollinated plants generally do not show the character B) single ovule in the ovary. D) flowers are large and colourful. A) feathery stigmas. C) well exposed stamens. Q21. Assertion: Insects visit flowers to gather honey. Reason: Attraction to flowers prevents the insects from damaging other parts. A) Both are true with the reason being correct explanation. B) Both are true but the reason is not the correct explanation. C) The assertion is true but the reason is wrong. D) Both the assertion and the reason are wrong. LEVEL 2 Q22. In _________ plant instead of pollen grains the male flowers are transferred to female flower A) Maize B) Ceratophyllum C) Nymphaea D) Vallisneria Q23. The number of chromosomes in leaf tip cell of a plant is 6. The number of chromosomes in each of the 4 cells of its pollen tetrad would be _________. A) 3 B) 6 C) 12 D) 24 Q24. For the formation of tetrasporic embryo sac, how many megaspore mother cells are required? A) 1 B) 2 C) 3 D) 4 Q25. Arrangement of nuclei in normal dicot embryo sac is ____________. A) 3 + 3 + 2 B) 2 + 3 + 3 C) 3 + 2 + 3 D) 2 + 4 + 2 Q26. An interesting modification of a flower shape for insect pollination occurs in some orchids in which a male insect mistakes the pattern on the orchid flower for the female of his species and tries to copulate with it, thereby pollinating the flower. This phenomenon is called _____________. A) Pseudoparthenocarpy B) Mimicry C) Pseudopollination D) Pseudocopulation B24.2

B24 – Sexual Reproduction in Flowering Plants 37 Q27. Which one of the following is a reference to xenogamy? A) Ripening of androecium earlier to gynoeciuim B) Pollen grains of one flower reaching the stigma of another flower present on the same plant C) Pollen grains of one flower, reaching the stigma of another flower present on a difference plant of the same species D) The inability of pollen tube to germinate on the stigma of the same flower Q28. When a flower is brightly coloured, scented and secretes nectar, it is most probably A) pollinated by wind. B) pollinated by insects. C) an insectivorous plant. D) sterile flower. Q29. Which of the following statements are true I. Endothecium lies below epidermis II. Fusion of egg with male gamete is called apogamy III. Synergids are haploid IV. Point at which funicle touches the ovule is called raphe A) I and IV B) I and II C) I and III D) Only I B24.2

B24 – Sexual Reproduction in Flowering Plants 38 B24.3 Double fertilization: Process and Significance CONCEPTS 1. Steps occurring during syngamy. 2. Triple fusion. 3. Reasons for endosperm development. 4. Nuclear endosperm. 5. Cellular endosperm. 6. Embryogenesis. 7. Organs involved in a dicot and a monocot embryo and will be able to describe the process in their development. 8. Seed and list out the parts of a seed. 9. Non-endospermic seed. 10. How fruit arises from the ovary and list out the parts of the fruit. 11. True and a false fruit and process how they develop. 12. How a parthenocarpic fruit arises from the ovary. 13. Apomixis and polyembryony. 14. Characteristics of fruit and seeds. PRE-READING Category Chapter in HSC Section in HSC Chapter in NCERT Section in NCERT 8.4 2 2.3 REQUIRED 8 PRE-READING EXERCISE LEVEL 1 Q1. In a flowering plant, the pollen tube first arrives in ___________. A) egg B) an antipodal cell C) a synergid D) central cell Q2. If the number of chromosomes in egg cell is 8, then what is the number of chromosmes in endosperm? A) 24 B) 8 C) 16 D) 12 Q3. Banana fruits are seedless, because A) auxins are sprayed for rapid development of fruits. B) of vegetative propagation of plants. C) of triploid plants. D) fruits are artificially ripened. Q4. Which of the following is the result of double fertilization? A) Cotyledon B) Nucellus C) Endosperm D) None of these Q5. Flowering dependent on cold treatment is _____________. A) cryotherapy B) cryogenics C) cryoscopy D) vernalization B24.3

B24 – Sexual Reproduction in Flowering Plants 39 Q6. After fertilization the ovary wall forms _____________. A) testa B) perisperm C) pericarp D) tegmen D) both A & B Q7. The role of double fertilization in angiosperms is to produce _____________. D) embryo sac A) endosperm B) zygote C) cotyledons Q8. The fertilization occurs in the _____________. A) ovary B) ovule C) nucellus LEVEL 2 Q9. Which of the following floral part forms the pericarp after fertilization? A) Nucellus B) Outer integument C) Ovary wall D) Inner integument Q10. Double fertilization involves fertilization of A) the egg by two male gametes. B) two eggs in the same embryo sac by two sperms brought by one pollen tube. C) the egg and the central cell by two sperms brought by different pollen tubes. D) the egg and the central cell by two sperms brought by the same pollen tube. IN CLASS EXERCISE LEVEL 1 Q1. When a diploid female plant is crossed with a tetraploid male, the ploidy of endosperm cells in the resulting seed is ____________. A) haploid B) diploid C) triploid D) tetraploid Q2. The process of fusion between male nucleus and egg nucleus is called ____________. A) triple fusion B) double fertilization C) conjugation D) syngamy Q3. Tegmen develops from ____________. B) outer integument A) inner integument D) chalaza C) funicle Q4. How many diploid nuclei are there in a fertilized embryo – sac? A) One B) Two C) Three D) Four Q5. Scutellum is _____________. B) embryo C) seed D) fruit A) cotyledon Q6. Final product of sexual reproduction in angiosperm ____________. A) seed B) flower C) fruit D) plant Q7. Nutritive tissue in the seed is ____________. A) perisperm B) monosperm C) endosperm D) nucellus Q8. Seed is a form of converted _____________. A) ovary B) embryo C) endosperm D) ovule Q9. Viability of a seed breaks its _____________. A) seed coat B) endosperm C) cotyledons D) dormancy B24.3

B24 – Sexual Reproduction in Flowering Plants 40 Q10. Disadvantage of hybrid seeds is A) unhealthy progenies. B) yield is reduced. C) every time hybrid seeds have to be produced to get the same result. D) sterility is more. Q11. Which of the following statements is not correct about somatic embryogenesis? A) A somatic embryo develops from a somatic cell. B) The pattern of development of a somatic embryo is comparable to that of a zygotic embryo. C) Somatic embryos can develop from microspores. D) Somatic embryo is induced usually by an auxin such as 2, 4 − ������. Q12. Which of the following statement(s) is/are incorrect? I. Endosperm formation starts prior to first division of zygote. II. Angiospermic endosperm is mostly 3������ while the gymnospermic one is ������. III. The most common type of endosperm is nuclear. IV. Coconut has both liquid nuclear (multinucleate) and cellular endosperm. V. Milky water of green tender coconut is liquid female gametophyte. A) (I) and (II) B) Only (III) C) Only (V) D) Only (II) Q13. Study the following statements and select the correct option. I. Tapetum nourishes the developing pollen grains. II. Hilum represents the junction between ovule and funicle. III. In aquatic plants, such as water hyacinth and water lily, pollination is by water. IV. The primary endosperm nucleus is triploid. A) (I) and (II) are correct but (II) and (IV) are incorrect. B) (I) and (II) are correct but (IV) are correct but (III) is incorrect. C) (II), (III) and (IV) are correct but (I) is incorrect. D) (I) and (IV) are correct but (II) and (III) are incorrect. Q14. Seeds are adaptively important because B) (II) and (III) D) All of the above I. they maintain dormancy. II. they protect young plants during vulnerable stages. III. they store food for young plants, and facilitate dispersal. Identify the correct reasons. A) (I) and (III) C) (I) and (II) Q15. Match the items given in column-I with those given in column-II and choose the correct option given below. Column-I Column-II a) Parthenocarpy i. Inactive state b) Polyembryony ii. Meiosis and syngamy are absent c) Apomixis iii. Extra embryos d) Dormancy iv. Seedless fruit A) a – i; b – ii; c – iii; d – iv B) a – iv; b – iii; c – ii; d – i C) a – iv; b – i; c – ii; d – iii D) a – iii; b – ii; c – i; d – iv B24.3

B24 – Sexual Reproduction in Flowering Plants 41 Q16. Match the items given in column-I with their examples given in column-II and identify the correct option. Column-I Column-II a) Coleorhiza i. Grapes b) Food storing tissue ii. Mango c) Parthenocarpic fruit iii. Maize d) Single seeded fruit developing from monocarpellary superior ovary iv. Radicle e) Membranous seed coat v. Endosperm A) a – iii; b – i; c – iv; d – ii; e – v B) a – iv; b – ii; c – v; d – i; e – iii C) a – v; b – i; c – iii; d – iv; e – ii D) a – iv; b – v; c – i; d – ii; e – iii Q17. Diagram given below shows the stages in embryogenesis in a typical dicot plant (Capsella). Identify the structures ������ to ������ respectively. A) Suspensor, Radicle, Plumule, Cotyledons B) Hypophysis, Radicle, Plumule, Cotyledons C) Suspensor, Plumule, Radicle, Cotyledons D) Suspensor, Radicle, Plumule, Hypocotyls Q18. Identified ������, ������, ������ and ������ in the given figure of false fruit of apple. A) ������ −Mesocarp; ������ −Endocarp; ������ −Seed; ������ −Thalamus B) ������ −Seed; ������ −Thalamus; ������ −Mesocarp; ������ −Endocarp C) ������ −Thalamus; ������ −Seed; ������ −Endocarp; ������ −Mesocarp D) ������ −Mesocarp; ������ −Endocarp; ������ −Seed; ������ −Thalamus Q19. Choose the option showing the correct labelling ������, ������, ������ and ������ in the given figure of a dicot embryo. A) ������ −Hypocotyl; ������ −Cotyledons; ������ −Root cap; ������ −Radicle B) ������ −Cotyledons; ������ −Hypocotyl; ������ −Root cap; ������ −Radicle C) ������ −Cotyledons; ������ −Hypocotyl; ������ −Radicle; ������ −Root cap D) ������ −Cotyledons; ������ −Radicle; ������ −Hypocotyl; ������ −Root cap B24.3

B24 – Sexual Reproduction in Flowering Plants 42 Q20. The given figure shows the ������. ������ of a monocot embryo. Choose the correct labelling for ������, ������, ������ and ������ marked in the figure from the options given below. A) ������ −Coleoptile; ������ −Scutellum; ������ −Epiblast; ������ −Coleorhiza B) ������ −Scutellum; ������ −Coleoptile; ������ −Coleorhiza; ������ −Epiblast C) ������ −Scutellum; ������ −Epiblast; ������ −Coleoptile; ������ −Coleorhiza D) ������ −Scutellum; ������ −Coleoptile; ������ −Epiblast; ������ −Coleorhiza Q21. Match the columns and find the correct option Column I Column-II a) Parthenocarpy i. Lodoicea b) Polyembryony ii. Banana c) Largest seed iii. Mango d) Seeds from Arctic tundra iv. Orchid v. Lupinus A) a – ii; b – iii; c – i; d – iv B) a – ii; b – iii; c – i; d – v C) a – iv; b – iii; c – iv; d – ii; D) a – v; b – iii; c – iv; d – ii Q22. Assertion: 7 celled, 8 nucleate and monosporic embryo sac is called polygonum type of embryo sac. Reason: It was discovered by Hofmeister for the first time in polygonum. A) Both the assertion and the reason are true with reason being the correct explanation. B) Both the assertion and the reason true but reason is not the correct explanation. C) The assertion is true but the reason is wrong. D) Both the assertion and the reason are wrong. HOMEWORK LEVEL 1 B) stimulate division of generative cell. D) guide the entry of pollen tube. Q1. Function of filiform apparatus is to A) recognize the suitable pollen at stigma. B) liquid nucellus. C) produce nectar. D) liquid endosperm. Q2. Milky water of tender coconut is A) liquid gametes. C) liquid female gametophyte. B24.3

B24 – Sexual Reproduction in Flowering Plants 43 Q3. It is process of embryo sac formation from cell of nucellus, without undergoing meiosis _____________. A) polyembryony B) incompatibility C) parthenocarpy D) parthenogenesis Q4. Which of the following is not true for double fertilization? A) Discovered by Nawaschin. B) Male gamete and secondary nucleus fused to form endosperm nucleus. C) Endosperm nucleus is diploid. D) Endosperm provides nutrition to embryo. Q5. Raphe is A) part of flower. B) funicle attached to ovule. C) ridge formed by funiculus. D) part of nucellus. Q6. An enzyme that can stimulate germination of barley seeds is ____________. A) lipase B) protease C) invertase D) ������- amylase Q7. The plant part which consists of two generations one within the other is _____________. A) germinated pollen grain B) embryo C) unfertilized ovule D) seed Q8. Sperm and egg nuclei fuse due to A) base pairing of their DNA and RNA. B) formation of hydrogen bonds. C) mutual attraction due to differences in electrical charges. D) attraction of their protoplasts. Q9. Female gametophyte of angiosperms is represented by _______________. A) ovule B) megaspore mother cell C) embryo sac D) nucellus Q10. Parthenocarpic tomato fruits can be produced by A) removing androecium of flowers before pollen grains are released. B) treating the plants with low concentrations of gibberellic acid and auxins. C) raising the plants from vernalized seeds. D) treating the plants with phenylmercuric acetate. Q11. Which one of the following statement is correct? A) Hard outer layer of pollen is called intine. B) Sporogenous tissue is haploid. C) Endothecium produces the microspores. D) Tapetum nourishes the developing pollen. Q12. Which one of the following statements is correct? A) Mango is a parthenocarpic fruit. B) A proteinaceous aleurone layer is present in maize grain. C) A sterile pistil is called staminode. D) The seed in grasses is not endospermic. B24.3

B24 – Sexual Reproduction in Flowering Plants 44 Q13. Select the correct statements from the following. I. Endosperm is generally triploid in angiosperms. II. All angiosperms have monosporic and endosporic embryo sac. III. Angiosperms are characterized by double fertilization. IV. All angiosperms show indirect pollination and siphonogamy. A) I, II & III B) II, III, & IV C) I, III & IV D) I, II, III & IV Q14. In flowering plants, double fertilization involves A) fertilization of egg cell and central cell by two male gametes is brought by the same pollen tube. B) fertilization of egg cell by two male gametes. C) fertilization of egg cell and central cell by two male gametes brought by different pollen tubes. D) fertilization of two egg cells by two male gametes brought by same pollen tube. Q15. Nitsch was able to get strawberries of different shapes by B) removing the perianth. D) inserting an alcohol dipped needle into ovary. A) splitting the ovary. C) selectively removing some carpels. Q16. What are chromosome numbers in the following respectively (I) Synergid of Gossypium (II) Leaf cells in Allium (III) Endosperms of Saccharum? A) 48, 16, 36 B) 52, 26, 32 C) 26, 16, 120 D) 48, 96, 24 Q17. Assertion: In some species of asteraceae and poaceae, seeds are formed without fertilization. Reason: Formation of fruit without fertilization is called parthenocarpy. A) Both the assertion and the reason are true with the reason being the correct explanation. B) Both the assertion and the reason are true but the reason is not the correct explanation. C) The assertion is true but the reason is wrong. D) Both the assertion and the reason are wrong. Q18. Which of the following is the correct chronological order of the division taking place through an apical or embryo cell to a sixteen cell stage? A) Vertical division → Transverse division → Division at right angles to both the previous divisions → Periclinal division B) Vertical division → Vertical division at right angles to the first division → Division at right angles to both the previous divisions → Periclinal division C) Vertical division → Transverse division → Periclinal division D) Vertical division → Vertical division at right angles to the first division → Transverse division → Periclinal division Q19. Part of endosperm remains liquid in coconut because A) karyokinesis is not followed by cytokinesis. B) karyokinesis is followed by cytokinesis. C) formation of liquid endosperm is not dependent upon karyokinesis and cytokinesis. D) none of the above. Q20. Identify the wrong statement regarding post fertilization development. A) Ovary wall develops into pericarp. B) Outer integument of ovule develops into tegmen. C) Fusion nucleus (triple nucleus) develops into endosperm. D) Ovary develops into fruit. B24.3

B24 – Sexual Reproduction in Flowering Plants 45 LEVEL 2 Q21. Embryo sac is to ovule as _________ is to an anther. B) filament D) androecium A) stamen C) pollen grain Q22. In a typical complete, bisexual and hypogynous flower the arrangement of floral whorls on the thalamus from the outermost to the innermost is A) calyx, corolla, androecium and gynoecium. B) calyx, corolla, gynoecium and androecium. C) gynoecium, androecium, corolla and calyx. D) androecium, gynoecium, corolla and calyx. Q23. Why sometimes, even diploid offspring is produced through parthenogenesis? A) When offspring is produced without fertilization of diploid egg cell. B) When offspring is produced through fertilization of diploid egg cell. C) When offspring is produced without fertilization of haploid egg cell. D) When offspring is produced through fertilization of haploid egg cell. Q24. Match the following ovular structures in Column I with post – fertilization structures in column II and select the correct alternative Column I Column II a. Ovule 1. Endosperm b. Funiculus 2. Aril c. Nucellus 3. Seed d. Polar nuclei 4. Perisperm Codes a. b. c. d. A) 2 3 4 1 B) 2 3 1 4 C) 3 2 4 1 D) 3 2 1 4 Q25. Total number of meiotic divisions required for forming 100 zygotes/100 grains of wheat are _________. A) 100 B) 75 C) 125 D) 50 Q26. Number of meiotic divisions required to produce 200/400 seeds of pea would be ___________. A) 200/400 B) 400/800 C) 300/600 D) 250/500 B24.3

B24 – Sexual Reproduction in Flowering Plants 46 Answer Key Q16. B Q17. C B24.1 SEXUAL REPRODUCTION IN PLANTS Q18. A Q19. B PRE-READING EXERCISE Q4. B LEVEL 2 Q20. A LEVEL 1 Q5. D Q21. C Q6. D Q24. D Q22. D Q1. C Q7. D Q25. C Q23. D Q2. C Q8. D Q24. A Q3. A Q9. A HOMEWORK Q25. A Q4. D Q10. A Q26. D Q5. C Q11. A LEVEL 1 Q27. D Q6. A Q12. C Q28. A Q7. C Q13. B Q1. B Q29. B Q8. C Q14. D Q2. B Q30. D Q15. A Q3. D LEVEL 2 Q16. D Q4. B LEVEL 2 Q9. A Q17. B Q5. B Q31. B Q10. A Q18. D Q6. D Q32. A Q19. C Q7. C Q33. C IN CLASS EXERCISE Q20. A Q8. A Q34. B LEVEL 1 Q21. B Q9. B Q22. A Q10. B Q5. A Q1. C Q23. B Q11. C Q6. B Q2. A Q12. A Q7. C Q3. B Q13. C Q8. D Q14. C Q9. A Q15. B Q10. B Q11. C B24.2 POLLINATION: TYPES AND AGENCIES Q12. A Q13. C PRE-READING EXERCISE IN CLASS EXERCISE Q13. D Q14. A Q14. D Q15. B LEVEL 1 LEVEL 1 Q15. A Q16. B Q17. B Q1. D Q1. A LEVEL 2 Q18. A Q2. A Q2. B Q16. B Q19. C Q3. C Q3. A Q17. C Q4. D Q4. C Q5. C Q5. D HOMEWORK Q6. D Q6. C LEVEL 1 Q7. D Q7. A Q1. B Q8. B Q2. C LEVEL 2 Q9. C Q3. D Q10. C Q4. B Q8. A Q11. C Q9. C Q12. B Q10. D Ans.

B24 – Sexual Reproduction in Flowering Plants 47 Q20. D LEVEL 2 Q24. A Q28. B Q21. C Q25. C Q29. C Q22. D Q26. D Q23. A Q27. C B24.3 DOUBLE FERTILIZATION: PROCESS AND SIGNIFICANCE PRE-READING EXERCISE IN CLASS EXERCISE Q17. A Q10. B Q18. C Q11. D LEVEL 1 LEVEL 1 Q19. B Q12. B Q20. D Q13. C Q1. C Q1. D Q21. B Q14. A Q2. A Q2. D Q22. C Q15. C Q3. C Q3. A Q16. C Q4. C Q4. A HOMEWORK Q17. B Q5. D Q5. A Q18. D Q6. C Q6. A LEVEL 1 Q19. A Q7. D Q7. C Q20. B Q8. D Q8. D Q1. D Q9. D Q2. D LEVEL 2 LEVEL 2 Q10. C Q3. D Q11. C Q4. C Q21. C Q9. C Q12. C Q5. C Q22. A Q10. D Q13. B Q6. D Q23. A Q14. D Q7. D Q24. C Q15. B Q8. D Q25. C Q16. D Q9. C Q26. D Ans.