Flower Biology Question Paper

Section A: Multiple Choice Questions (MCQs) - 100 Questions (1 mark each)

Instructions: Choose the correct option for each question.

1. How many main whorls are present in a typical bisexual flower? a) 2 b) 3 c) 4 d) 5

2. The outermost whorl of a flower is called: a) Corolla b) Calyx c) Androecium d) Gynoecium

3. The green, leaf-like structures that protect the flower bud are: a) Petals b) Sepals c) Stamens d) Carpels

4. The main function of petals is to: a) Protect the bud b) Produce pollen c) Attract pollinators d) Store food

5. The male reproductive part of a flower is called: a) Gynoecium b) Androecium c) Corolla d) Calyx

6. Each stamen consists of: a) Anther only b) Filament only c) Anther and filament d) Stigma and style

7. The sac-like structure that produces pollen is: a) Filament b) Anther c) Stigma d) Style

8. The female reproductive part of a flower is: a) Stamen b) Anther c) Gynoecium d) Filament

9. The receptive tip that receives pollen is called: a) Style b) Ovary c) Stigma d) Anther

10. The ovary contains: a) Pollen grains b) Nectar c) Ovules d) Stamens

11. The transfer of pollen from anther to stigma is called: a) Fertilization b) Germination c) Pollination d) Reproduction

12. When pollen transfers within the same flower, it is: a) Cross-pollination b) Self-pollination c) Wind pollination d) Water pollination

13. Cross-pollination occurs between: a) Same flower b) Different flowers of same plant c) Different plants of same species d) Different species

14. Wind pollination is called: a) Entomophily b) Hydrophily c) Anemophily d) Zoophily

15. Water pollination is termed as: a) Anemophily b) Hydrophily c) Entomophily d) Ornithophily

16. Insect pollination is known as: a) Anemophily b) Hydrophily c) Entomophily d) Chiropterophily

17. Wind-pollinated flowers are typically: a) Large and colorful b) Small and inconspicuous c) Fragrant d) Rich in nectar

18. Which is an example of wind-pollinated plant? a) Rose b) Hibiscus c) Maize d) Sunflower

19. Insect-pollinated flowers are usually: a) Small and dull b) Large and colorful c) Without nectar d) Odorless

20. The fusion of male and female gametes is called: a) Pollination b) Fertilization c) Germination d) Dispersal

21. After fertilization, the ovary develops into: a) Seed b) Fruit c) Root d) Leaf

22. After fertilization, ovules develop into: a) Fruits b) Flowers c) Seeds d) Roots

23. The fruit wall is called: a) Testa b) Pericarp c) Endosperm d) Cotyledon

24. Fruits with dry pericarp at maturity are: a) Fleshy fruits b) Dry fruits c) Simple fruits d) Compound fruits

25. Which is an example of dry fruit? a) Mango b) Apple c) Pea pod d) Orange

26. The outermost layer of pericarp is: a) Mesocarp b) Endocarp c) Epicarp d) Exocarp

27. The middle fleshy layer of fruit is: a) Epicarp b) Mesocarp c) Endocarp d) Pericarp

28. The innermost layer of pericarp is: a) Epicarp b) Mesocarp c) Endocarp d) Exocarp

29. A fertilized ovule is called: a) Fruit b) Flower c) Seed d) Embryo

30. The outer protective layer of seed is: a) Pericarp b) Seed coat c) Cotyledon d) Endosperm

31. The embryonic root is called: a) Plumule b) Radicle c) Cotyledon d) Hypocotyl

32. The embryonic shoot is termed: a) Radicle b) Plumule c) Cotyledon d) Epicotyl

33. Seed leaves are called: a) Sepals b) Petals c) Cotyledons d) Stamens

34. Seeds with one cotyledon are: a) Dicots b) Monocots c) Polycots d) Acotyledons

35. Seeds with two cotyledons are: a) Monocots b) Dicots c) Polycots d) Acotyledons

36. Which is a monocot seed? a) Bean b) Pea c) Rice d) Gram

37. Which is a dicot seed? a) Maize b) Rice c) Wheat d) Bean

38. The process by which seed sprouts is: a) Pollination b) Fertilization c) Germination d) Photosynthesis

39. For germination, seeds require: a) Only water b) Only air c) Only warmth d) Water, air, and warmth

40. In epigeal germination: a) Cotyledons remain below soil b) Cotyledons come above soil c) Only roots emerge d) Nothing emerges

41. In hypogeal germination: a) Cotyledons come above soil b) Cotyledons remain below soil c) Seeds don't germinate d) Only leaves emerge

42. Bean shows which type of germination? a) Hypogeal b) Epigeal c) Aerial d) Underground

43. Maize shows which type of germination? a) Epigeal b) Hypogeal c) Aerial d) Surface

44. The part of flower stalk to which flower parts are attached: a) Pedicel b) Receptacle c) Peduncle d) Rachis

45. Nectar guides help in: a) Protection b) Attracting pollinators c) Seed dispersal d) Water storage

46. Large and feathery stigmas are found in: a) Insect-pollinated flowers b) Water-pollinated flowers c) Wind-pollinated flowers d) Self-pollinated flowers

47. Sticky pollen is found in: a) Wind-pollinated flowers b) Insect-pollinated flowers c) Water-pollinated flowers d) All flowers

48. Vallisneria is pollinated by: a) Wind b) Water c) Insects d) Birds

49. The male gametes travel through: a) Style b) Pollen tube c) Filament d) Anther

50. The zygote develops into: a) Seed coat b) Fruit c) Embryo d) Endosperm

51. Which part of flower withers after fertilization? a) Ovary b) Ovules c) Petals d) All parts

52. The edible part of mango is: a) Epicarp b) Mesocarp c) Endocarp d) Seed

53. The stone of mango is: a) Epicarp b) Mesocarp c) Endocarp d) Seed

54. In orange, the endocarp is: a) Hard and stony b) Membranous c) Fleshy d) Absent

55. Food for developing embryo is stored in: a) Seed coat b) Cotyledons c) Radicle d) Plumule

56. The first structure to emerge during germination is: a) Plumule b) Radicle c) Cotyledon d) Leaf

57. Oxygen is required during germination for: a) Photosynthesis b) Respiration c) Transportation d) Protection

58. Enzymes become active during germination due to: a) Light b) Water c) Air d) Soil

59. The hypocotyl is the part of stem: a) Above cotyledons b) Below cotyledons c) Between leaves d) In roots

60. Groundnut is an example of: a) Fleshy fruit b) Dry fruit c) Simple fruit d) Multiple fruit

61. Tomato is classified as: a) Dry fruit b) Fleshy fruit c) Aggregate fruit d) Composite fruit

62. The function of filament is to: a) Produce pollen b) Support anther c) Receive pollen d) Store nectar

63. Cross-pollination is advantageous because it: a) Requires less energy b) Produces genetic variation c) Is faster d) Needs no agents

64. Self-pollination results in: a) Genetic variation b) Hybrid vigor c) Genetic uniformity d) Sterile offspring

65. Pollen grains contain: a) Female gametes b) Male gametes c) Zygotes d) Seeds

66. The style connects: a) Anther to filament b) Stigma to ovary c) Ovary to ovules d) Petals to sepals

67. Bisexual flowers contain: a) Only male parts b) Only female parts c) Both male and female parts d) Neither male nor female parts

68. The process after fertilization where flower changes to fruit is: a) Pollination b) Germination c) Fruit development d) Seed formation

69. Unwettable pollen is characteristic of: a) Wind pollination b) Water pollination c) Insect pollination d) Self pollination

70. Pine is pollinated by: a) Insects b) Water c) Wind d) Birds

71. Hibiscus is pollinated by: a) Wind b) Water c) Insects d) Self

72. The receptacle is part of: a) Stem b) Root c) Leaf d) Flower

73. After germination, radicle develops into: a) Shoot system b) Root system c) Leaf d) Flower

74. After germination, plumule develops into: a) Root system b) Shoot system c) Fruit d) Seed

75. Water is needed for germination to: a) Provide food b) Soften seed coat c) Provide minerals d) Make soil fertile

76. Temperature affects germination by influencing: a) Seed color b) Enzyme activity c) Seed size d) Soil type

77. The part of embryo that emerges first during germination: a) Cotyledon b) Plumule c) Radicle d) Hypocotyl

78. In wheat, the pericarp is: a) Fleshy b) Dry c) Juicy d) Soft

79. The transfer of food from endosperm is done by: a) Radicle b) Plumule c) Cotyledons d) Seed coat

80. Grasses are examples of: a) Insect pollination b) Water pollination c) Wind pollination d) Self pollination

81. The bright colors of petals are for: a) Protection b) Attracting pollinators c) Photosynthesis d) Storing food

82. Spiny pollen is found in: a) Wind-pollinated flowers b) Insect-pollinated flowers c) Water-pollinated flowers d) All flowers

83. The optimal conditions for germination include: a) Darkness only b) Light only c) Moisture, warmth, and air d) Cold and dry conditions

84. Sunflower is an example of: a) Wind pollination b) Water pollination c) Insect pollination d) Self pollination

85. The embryo consists of: a) Only radicle b) Only plumule c) Radicle and plumule d) Only cotyledons

86. Pea is an example of: a) Monocot b) Dicot c) Polycot d) Non-cotyledon

87. The seed coat protects: a) Fruit b) Flower c) Embryo d) Root

88. Hydrilla is pollinated by: a) Wind b) Water c) Insects d) Animals

89. The function of sepals is mainly: a) Attraction b) Protection c) Reproduction d) Nutrition

90. Large amounts of pollen are produced by: a) Insect-pollinated flowers b) Water-pollinated flowers c) Wind-pollinated flowers d) Self-pollinated flowers

91. The apple we eat is mainly: a) Epicarp b) Mesocarp c) Endocarp d) Seed

92. Gram seed is: a) Monocot b) Dicot c) Polycot d) Acotyledon

93. The stalk of anther is: a) Style b) Stigma c) Filament d) Pedicel

94. Rose is pollinated by: a) Wind b) Water c) Insects d) Self

95. The part of pistil that contains ovules: a) Stigma b) Style c) Ovary d) Filament

96. Fertilization occurs in: a) Anther b) Stigma c) Ovule d) Petal

97. The skin of fruit is: a) Mesocarp b) Endocarp c) Epicarp d) Pericarp

98. Cotyledons provide: a) Protection b) Support c) Food d) Water

99. Maize grain is actually a: a) Seed b) Fruit c) Root d) Stem

100. The development of seed from ovule occurs after: a) Pollination b) Fertilization c) Germination d) Fruit formation

Section B: Short Answer Questions (1 mark each) - 100 Questions

Instructions: Write brief answers in one or two sentences.

1. Define pollination.
2. What is the function of sepals?
3. Name the male reproductive part of a flower.
4. What are the two parts of a stamen?
5. Define fertilization.
6. What develops from the ovary after fertilization?
7. What develops from ovules after fertilization?
8. Name the three layers of pericarp.
9. What is germination?
10. Name the embryonic root.
11. Name the embryonic shoot.
12. What are cotyledons?
13. Define self-pollination.
14. Define cross-pollination.
15. What is anemophily?
16. What is entomophily?
17. What is hydrophily?
18. Name two wind-pollinated plants.
19. Name two insect-pollinated plants.
20. What is the function of petals?
21. What is the receptacle?
22. Name the female reproductive part of a flower.
23. What are the three parts of carpel?
24. What is the function of stigma?
25. What is the function of style?
26. What does the ovary contain?
27. Where are pollen grains produced?
28. What is the function of filament?
29. What is a bisexual flower?
30. Name the four whorls of a flower.
31. What is epicarp?
32. What is mesocarp?
33. What is endocarp?
34. What is pericarp?
35. Give two examples of dry fruits.
36. Give two examples of fleshy fruits.
37. What is seed coat?
38. What is an embryo?
39. What are monocot seeds?
40. What are dicot seeds?
41. Give two examples of monocot seeds.
42. Give two examples of dicot seeds.
43. What is epigeal germination?
44. What is hypogeal germination?
45. Name three conditions required for germination.
46. What is the function of radicle?
47. What is the function of plumule?
48. What is the function of cotyledons?
49. Why do wind-pollinated flowers produce large amounts of pollen?
50. Why are insect-pollinated flowers colorful?
51. What happens to petals after fertilization?
52. What happens to stamens after fertilization?
53. Why do wind-pollinated flowers lack fragrance?
54. Why do insect-pollinated flowers have sticky pollen?
55. What is the function of nectar?
56. What are nectar guides?
57. Why are wind-pollinated flowers small?
58. What type of stigma do wind-pollinated flowers have?
59. What makes pollen grains suitable for wind dispersal?
60. What makes pollen grains suitable for insect dispersal?
61. Why is cross-pollination beneficial?
62. What is the disadvantage of self-pollination?
63. How does water help in germination?
64. How does temperature affect germination?
65. Why is oxygen needed for germination?
66. What emerges first during germination?
67. What is hypocotyl?
68. What is epicotyl?
69. Where does fertilization take place?
70. What is a zygote?
71. From what does the embryo develop?
72. What protects the seed?
73. What stores food in dicot seeds?
74. What stores food in monocot seeds?
75. How many cotyledons does a bean seed have?
76. How many cotyledons does a maize seed have?
77. What is the edible part of an apple?
78. What is the stone in a mango?
79. What type of endocarp does an orange have?
80. Why are fruits important for plants?
81. How do fruits help in seed dispersal?
82. What withers away after fruit formation?
83. What is the difference between a fruit and a seed?
84. Why do some flowers have bright colors?
85. Why do some flowers have fragrance?
86. What attracts insects to flowers?
87. How is pollen transferred in wind pollination?
88. How is pollen transferred in water pollination?
89. What type of pollen is found in water-pollinated plants?
90. Give an example of water-pollinated plant.
91. What happens when pollen grain reaches stigma?
92. What grows from the pollen grain?
93. Through what structure do male gametes travel?
94. What forms when male and female gametes fuse?
95. What is the fate of the zygote?
96. Why do seeds need a protective coat?
97. What activates enzymes during germination?
98. What softens the seed coat during germination?
99. What provides energy for germination?
100. How do cotyledons help in germination?

Section C: Short Answer Questions (2 marks each) - 25 Questions

Instructions: Write detailed answers in 2-3 sentences or provide explanations with examples.

1. Describe the structure and function of the androecium.

2. Explain the structure and function of the gynoecium.

3. Compare self-pollination and cross-pollination with one example each.

4. Describe the characteristics of wind-pollinated flowers with two examples.

5. Describe the characteristics of insect-pollinated flowers with two examples.

6. Explain the process of fertilization in flowering plants.

7. Describe what happens to different parts of the flower after fertilization.

8. Differentiate between dry fruits and fleshy fruits with examples.

9. Describe the three layers of pericarp in fleshy fruits.

10. Compare monocotyledonous and dicotyledonous seeds with examples.

11. Explain the conditions required for seed germination and why each is important.

12. Compare epigeal and hypogeal germination with examples.

13. Describe the structure of a seed and the function of each part.

14. Explain how wind pollination is adapted in flowering plants.

15. Explain how insect pollination is adapted in flowering plants.

16. Describe the journey of pollen from anther to fertilization.

17. Explain the importance of cross-pollination over self-pollination.

18. Describe the formation of fruit from flower after fertilization.

19. Explain the role of different agents in cross-pollination.

20. Describe the structure of embryo and function of its parts.

21. Explain how water-pollinated flowers are adapted for their mode of pollination.

22. Compare the pollen characteristics of wind and insect-pollinated flowers.

23. Describe the changes that occur in a flower after successful pollination and fertilization.

24. Explain the significance of cotyledons in seed germination.

25. Describe how the structure of different types of fruits helps in seed protection and dispersal.

Section D: Long Answer Questions (3 marks each) - 25 Questions

Instructions: Write comprehensive answers with proper explanations, examples, and diagrams where necessary.

1. Describe the four whorls of a flower in detail, including their structure and functions.

2. Explain the different types of pollination and describe the adaptations of flowers for each type.

3. Describe the complete process of fertilization in flowering plants, from pollination to zygote formation.

4. Explain the formation of fruits and seeds after fertilization, describing the changes in different flower parts.

5. Compare and contrast the characteristics of wind-pollinated and insect-pollinated flowers with suitable examples.

6. Describe the structure of a seed and explain the process of germination with necessary conditions.

7. Explain the different types of seed germination with examples and describe what happens during each type.

8. Describe the structure and classification of fruits, explaining the significance of different fruit types.

9. Explain the agents of cross-pollination and describe the adaptations of flowers for each agent.

10. Describe the male and female reproductive parts of a flower and explain their roles in reproduction.

11. Explain how the structure of wind-pollinated flowers is adapted to their mode of pollination, giving specific examples.

12. Describe the journey from pollination to seed formation, explaining each step in detail.

13. Compare monocotyledonous and dicotyledonous seeds in terms of structure, germination, and examples.

14. Explain the importance of different environmental conditions for seed germination and describe what happens if any condition is absent.

15. Describe the structure of different types of fruits and explain how each type helps in seed protection and dispersal.

16. Explain the process of cross-pollination by insects, describing the adaptations of both flowers and insects.

17. Describe the formation and structure of the embryo, explaining the development from zygote to mature embryo.

18. Explain the advantages and disadvantages of self-pollination and cross-pollination with suitable examples.

19. Describe the complete life cycle of a flowering plant from pollination to germination of the next generation.

20. Explain the structural adaptations of water-pollinated flowers and compare them with wind and insect-pollinated flowers.

21. Describe the process of fruit development from flower, explaining the fate of each floral part.

22. Explain the role of environmental factors in pollination and describe how different pollinators are attracted to flowers.

23. Describe the internal structure of a seed and explain how each part contributes to the development of a new plant.

24. Explain the significance of sexual reproduction in flowering plants and describe the mechanisms that ensure genetic diversity.

25. Describe the different methods of seed dispersal and explain how fruit structure is related to the method of dispersal.

Answer Key

Flower Biology Answer Script

Section A: Multiple Choice Questions (MCQs)

1. c) 4
2. b) Calyx
3. b) Sepals
4. c) Attract pollinators
5. b) Androecium
6. c) Anther and filament
7. b) Anther
8. c) Gynoecium
9. c) Stigma
10. c) Ovules
11. c) Pollination
12. b) Self-pollination
13. c) Different plants of same species
14. c) Anemophily
15. b) Hydrophily
16. c) Entomophily
17. b) Small and inconspicuous
18. c) Maize
19. b) Large and colorful
20. b) Fertilization
21. b) Fruit
22. c) Seeds
23. b) Pericarp
24. b) Dry fruits
25. c) Pea pod
26. c) Epicarp
27. b) Mesocarp
28. c) Endocarp
29. c) Seed
30. b) Seed coat
31. b) Radicle
32. b) Plumule
33. c) Cotyledons
34. b) Monocots
35. b) Dicots
36. c) Rice
37. d) Bean
38. c) Germination
39. d) Water, air, and warmth
40. b) Cotyledons come above soil
41. b) Cotyledons remain below soil
42. b) Epigeal
43. b) Hypogeal
44. b) Receptacle
45. b) Attracting pollinators
46. c) Wind-pollinated flowers
47. b) Insect-pollinated flowers
48. b) Water
49. b) Pollen tube
50. c) Embryo
51. c) Petals
52. b) Mesocarp
53. c) Endocarp
54. b) Membranous
55. b) Cotyledons
56. b) Radicle
57. b) Respiration
58. b) Water
59. b) Below cotyledons
60. b) Dry fruit
61. b) Fleshy fruit
62. b) Support anther
63. b) Produces genetic variation
64. c) Genetic uniformity
65. b) Male gametes
66. b) Stigma to ovary
67. c) Both male and female parts
68. c) Fruit development
69. b) Water pollination
70. c) Wind
71. c) Insects
72. d) Flower
73. b) Root system
74. b) Shoot system
75. b) Soften seed coat
76. b) Enzyme activity
77. c) Radicle
78. b) Dry
79. c) Cotyledons
80. c) Wind pollination
81. b) Attracting pollinators
82. b) Insect-pollinated flowers
83. c) Moisture, warmth, and air
84. c) Insect pollination
85. c) Radicle and plumule
86. b) Dicot
87. c) Embryo
88. b) Water
89. b) Protection
90. c) Wind-pollinated flowers
91. b) Mesocarp
92. b) Dicot
93. c) Filament
94. c) Insects
95. c) Ovary
96. c) Ovule
97. c) Epicarp
98. c) Food
99. b) Fruit
100. b) Fertilization

Section B: Short Answer Questions

1. Define pollination. The transfer of pollen grains from the anther to the stigma of a flower.

2. What is the function of sepals? To protect the flower in its bud stage.

3. Name the male reproductive part of a flower. Androecium.

4. What are the two parts of a stamen? Anther and filament.

5. Define fertilization. The fusion of the male gamete with the female gamete to form a zygote.

6. What develops from the ovary after fertilization? The fruit.

7. What develops from ovules after fertilization? The seeds.

8. Name the three layers of pericarp. Epicarp, mesocarp, and endocarp.

9. What is germination? The process by which a seed sprouts and grows into a new plant.

10. Name the embryonic root. Radicle.

11. Name the embryonic shoot. Plumule.

12. What are cotyledons? Seed leaves that store food for the developing embryo.

13. Define self-pollination. The transfer of pollen from the anther to the stigma of the same flower or another flower on the same plant.

14. Define cross-pollination. The transfer of pollen from the anther of a flower on one plant to the stigma of a flower on another plant of the same species.

15. What is anemophily? Pollination by wind.

16. What is entomophily? Pollination by insects.

17. What is hydrophily? Pollination by water.

18. Name two wind-pollinated plants. Grasses, Maize.

19. Name two insect-pollinated plants. Rose, Sunflower.

20. What is the function of petals? To attract pollinators.

21. What is the receptacle? The part of the flower stalk to which the parts of the flower are attached.

22. Name the female reproductive part of a flower. Gynoecium (or Pistil/Carpel).

23. What are the three parts of carpel? Stigma, style, and ovary.

24. What is the function of stigma? It is the receptive tip that receives pollen.

25. What is the function of style? It connects the stigma to the ovary.

26. What does the ovary contain? Ovules.

27. Where are pollen grains produced? In the anther.

28. What is the function of filament? It supports the anther.

29. What is a bisexual flower? A flower that has both male (androecium) and female (gynoecium) reproductive parts.

30. Name the four whorls of a flower. Calyx, Corolla, Androecium, and Gynoecium.

31. What is epicarp? The outermost layer of the fruit wall, forming the skin.

32. What is mesocarp? The middle, fleshy part of the fruit wall.

33. What is endocarp? The innermost layer of the fruit wall, which encloses the seed.

34. What is pericarp? The fruit wall, which develops from the ovary wall.

35. Give two examples of dry fruits. Pea pod, Groundnut.

36. Give two examples of fleshy fruits. Mango, Apple.

37. What is seed coat? The outer protective layer of the seed.

38. What is an embryo? The miniature plant within the seed.

39. What are monocot seeds? Seeds that contain a single cotyledon.

40. What are dicot seeds? Seeds that contain two cotyledons.

41. Give two examples of monocot seeds. Maize, Rice.

42. Give two examples of dicot seeds. Bean, Pea.

43. What is epigeal germination? Germination where the cotyledons are pushed above the soil surface.

44. What is hypogeal germination? Germination where the cotyledon remains below the soil surface.

45. Name three conditions required for germination. Moisture (water), warmth (suitable temperature), and air (oxygen).

46. What is the function of radicle? It develops into the root system.

47. What is the function of plumule? It develops into the shoot system.

48. Value of cotyledons? They store food for the developing embryo.

49. Why do wind-pollinated flowers produce large amounts of pollen? To increase the chances of pollen reaching a stigma, as wind dispersal is random.

50. Why are insect-pollinated flowers colorful? To attract insects for pollination.

51. What happens to petals after fertilization? They usually wither and fall off.

52. What happens to stamens after fertilization? They usually wither and fall off.

53. Why do wind-pollinated flowers lack fragrance? They do not need to attract pollinators like insects.

54. Why do insect-pollinated flowers have sticky pollen? To adhere to the bodies of insects.

55. What is the function of nectar? It serves as a reward for pollinators.

56. What are nectar guides? Markings on petals that direct pollinators to the nectar.

57. Why are wind-pollinated flowers small? They do not need to be large and attractive as they don't rely on pollinators.

58. What type of stigma do wind-pollinated flowers have? Large and feathery to effectively catch airborne pollen.

59. What makes pollen grains suitable for wind dispersal? They are light and dry.

60. What makes pollen grains suitable for insect dispersal? They are sticky or spiny.

61. Why is cross-pollination beneficial? It leads to genetic variation in the offspring.

62. What is the disadvantage of self-pollination? It results in less genetic diversity, which can be a disadvantage in changing environments.

63. How does water help in germination? It softens the seed coat and activates enzymes.

64. How does temperature affect germination? It affects the activity of enzymes required for the embryo's growth.

65. Why is oxygen needed for germination? For the respiration of the embryo to release energy for growth.

66. What emerges first during germination? The radicle (embryonic root).

67. What is hypocotyl? The part of the stem below the cotyledons.

68. What is epicotyl? The part of the stem above the cotyledons.

69. Where does fertilization take place? Inside the ovule.

70. What is a zygote? The cell formed by the fusion of male and female gametes.

71. From what does the embryo develop? From the zygote.

72. What protects the seed? The seed coat.

73. What stores food in dicot seeds? The cotyledons.

74. What stores food in monocot seeds? The endosperm (food is transferred by the cotyledon).

75. How many cotyledons does a bean seed have? Two.

76. How many cotyledons does a maize seed have? One.

77. What is the edible part of an apple? The fleshy receptacle (a fleshy fruit).

78. What is the stone in a mango? The hard and stony endocarp.

79. What type of endocarp does an orange have? A membranous endocarp.

80. Why are fruits important for plants? They protect the seeds and aid in their dispersal.

81. How do fruits help in seed dispersal? By being eaten by animals or by other mechanisms like wind or water dispersal.

82. What withers away after fruit formation? Sepals, petals, stamens, style, and stigma.

83. What is the difference between a fruit and a seed? A fruit develops from the ovary and contains seeds, while a seed develops from an ovule and contains the embryo.

84. Why do some flowers have bright colors? To attract pollinators.

85. Why do some flowers have fragrance? To attract pollinators.

86. What attracts insects to flowers? Bright colors, fragrance, and nectar.

87. How is pollen transferred in wind pollination? By being carried by the wind.

88. How is pollen transferred in water pollination? By being carried by water currents.

89. What type of pollen is found in water-pollinated plants? Light and unwettable pollen.

90. Give an example of water-pollinated plant. Vallisneria or Hydrilla.

91. What happens when pollen grain reaches stigma? It germinates and grows a pollen tube.

92. What grows from the pollen grain? A pollen tube.

93. Through what structure do male gametes travel? The pollen tube.

94. What forms when male and female gametes fuse? A zygote.

95. What is the fate of the zygote? It develops into the embryo.

96. Why do seeds need a protective coat? To protect the embryo and stored food from damage and drying out.

97. What activates enzymes during germination? Water/moisture.

98. What softens the seed coat during germination? Water/moisture.

99. What provides energy for germination? The breakdown of stored food through respiration.

100. How do cotyledons help in germination? They provide stored food for the embryo.

Section C: Short Answer Questions (2 marks each)

1. Describe the structure and function of the androecium. The androecium is the male reproductive whorl of a flower, consisting of units called stamens. Each stamen is made of a stalk-like filament that supports an anther, which is a sac-like structure that produces and contains pollen grains. The primary function of the androecium is to produce male gametes within these pollen grains for fertilization.

2. Explain the structure and function of the gynoecium. The gynoecium is the female reproductive whorl at the center of the flower, consisting of one or more carpels (or a pistil). Each carpel has three parts: the stigma (a receptive tip for pollen), the style (a stalk connecting the stigma to the ovary), and the ovary (a base containing ovules). Its function is to receive pollen and contain the ovules, which develop into seeds after fertilization.

3. Compare self-pollination and cross-pollination with one example each. Self-pollination is the transfer of pollen to the stigma of the same flower or another flower on the same plant (e.g., Pea). Cross-pollination is the transfer of pollen from a flower on one plant to the stigma of a flower on another plant of the same species (e.g., Rose). Self-pollination leads to genetic uniformity, while cross-pollination promotes genetic diversity.

4. Describe the characteristics of wind-pollinated flowers with two examples. Wind-pollinated (anemophilous) flowers are typically small, inconspicuous, and dull-colored, lacking scent and nectar. They produce large quantities of light, dry pollen to be easily carried by the wind, and their stigmas are often large and feathery to effectively trap airborne pollen. Examples include Maize and Grasses.

5. Describe the characteristics of insect-pollinated flowers with two examples. Insect-pollinated (entomophilous) flowers are usually large, brightly colored, and fragrant to attract insects. They often produce nectar as a reward and have sticky or spiny pollen that adheres to insect bodies. Their stigmas are also often sticky to receive the pollen. Examples include Rose and Sunflower.

6. Explain the process of fertilization in flowering plants. After a pollen grain lands on a compatible stigma (pollination), it germinates and grows a pollen tube down through the style to the ovary. The male gametes travel down this tube to an ovule. Fertilization occurs when one male gamete fuses with the female gamete (egg cell) inside the ovule to form a zygote.

7. Describe what happens to different parts of the flower after fertilization. After fertilization, the ovary develops into the fruit, and the ovules inside it develop into seeds. The other floral parts, including the sepals, petals, stamens, style, and stigma, typically wither and fall off as they are no longer needed.

8. Differentiate between dry fruits and fleshy fruits with examples. The main difference lies in the nature of the pericarp (fruit wall) at maturity. In dry fruits, the pericarp becomes dry and hard (e.g., Pea pod, Wheat). In fleshy fruits, the pericarp remains fleshy and juicy (e.g., Mango, Tomato).

9. Describe the three layers of pericarp in fleshy fruits. The pericarp of fleshy fruits has three layers. The epicarp is the outermost protective skin or peel. The mesocarp is the middle, fleshy, and often edible part that stores food. The endocarp is the innermost layer that encloses the seed(s) and can be hard and stony (like in a mango) or membranous (like in an orange).

10. Compare monocotyledonous and dicotyledonous seeds with examples. Monocotyledonous (monocot) seeds have a single cotyledon (e.g., Maize, Rice), and food is typically stored in the endosperm. Dicotyledonous (dicot) seeds have two cotyledons (e.g., Bean, Pea), which usually store the food for the embryo.

11. Explain the conditions required for seed germination and why each is important. Three conditions are essential for germination. Moisture is needed to soften the seed coat and activate enzymes. Warmth (a suitable temperature) is required for these enzymes to function optimally. Air (Oxygen) is necessary for the embryo to respire and release energy for growth.

12. Compare epigeal and hypogeal germination with examples. In epigeal germination, the cotyledons are pushed above the ground by the elongating hypocotyl (e.g., Bean). In hypogeal germination, the cotyledon(s) remain below the soil surface while the plumule emerges (e.g., Maize).

13. Describe the structure of a seed and the function of each part. A seed consists of a seed coat for protection, an embryo (the miniature plant), and stored food. The embryo has a radicle that develops into the root and a plumule that develops into the shoot. The cotyledon(s) store or transfer food to the embryo.

14. Explain how wind pollination is adapted in flowering plants. Plants adapted for wind pollination produce vast amounts of lightweight, dry pollen to maximize chances of dispersal. Their flowers are often small and lack petals, scent, or nectar, and they possess large, feathery stigmas to efficiently trap the wind-borne pollen.

15. Explain how insect pollination is adapted in flowering plants. Plants adapted for insect pollination have evolved features to attract pollinators. These include large, colorful petals, strong fragrances, and the production of nectar. Their pollen is often sticky or spiny to attach to insects, and stigmas are sticky to receive it.

16. Describe the journey of pollen from anther to fertilization. Pollen is released from the anther and transferred to a stigma by a pollinating agent. On the stigma, it germinates, growing a pollen tube through the style towards the ovary. Male gametes travel down the tube, enter an ovule, and one fuses with the egg cell, completing fertilization.

17. Explain the importance of cross-pollination over self-pollination. Cross-pollination is more important because it involves the fusion of gametes from two different parent plants, leading to genetic variation in the offspring. This genetic diversity increases the chances of adaptation and survival of the species in changing environmental conditions, whereas self-pollination leads to genetic uniformity.

18. Describe the formation of fruit from flower after fertilization. Following fertilization, the ovary of the flower begins to swell and mature into the fruit. The wall of the ovary develops into the pericarp (fruit wall). Simultaneously, the ovules inside the ovary develop into seeds, while other floral parts like petals and stamens wither away.

19. Explain the role of different agents in cross-pollination. Cross-pollination requires agents to transfer pollen between plants. Wind carries light, dry pollen over distances. Insects are attracted by colorful, scented flowers and transfer sticky pollen as they feed on nectar. Water can carry the pollen of some aquatic plants.

20. Describe the structure of embryo and function of its parts. The embryo is the young plant within a seed. It consists of the radicle, the embryonic root that grows downwards to form the root system, and the plumule, the embryonic shoot that grows upwards to form the stem and leaves. It also includes one or two cotyledons, which provide nourishment.

21. Explain how water-pollinated flowers are adapted for their mode of pollination. Water-pollinated (hydrophilous) flowers are typically small and inconspicuous. They produce pollen that is light and unwettable, allowing it to float on or in the water without being damaged, eventually reaching the stigma of another flower. Examples include Vallisneria and Hydrilla.

22. Compare the pollen characteristics of wind and insect-pollinated flowers. Pollen from wind-pollinated flowers is small, light, dry, and produced in very large quantities to be easily carried by air currents. In contrast, pollen from insect-pollinated flowers is larger, sticky or spiny to adhere to insect bodies, and produced in smaller quantities.

23. Describe the changes that occur in a flower after successful pollination and fertilization. After fertilization, the zygote develops into an embryo. The ovule turns into a seed, and the ovary wall develops into the fruit (pericarp). The sepals, petals, stamens, stigma, and style wither and fall off, as their functions are complete.

24. Explain the significance of cotyledons in seed germination. Cotyledons are vital for germination as they provide the initial food source for the growing embryo. In dicots, they store food directly, while in monocots, they help transfer food from the endosperm. This nourishment sustains the seedling until it can produce its own food through photosynthesis.

25. Describe how the structure of different types of fruits helps in seed protection and dispersal. Fleshy, edible fruits attract animals, which eat the fruit and disperse the seeds in their droppings. Dry, winged fruits (like in maples) are adapted for wind dispersal. Fruits with hooks or barbs (like burrs) attach to animal fur for dispersal, while buoyant, waterproof fruits can be dispersed by water.

Section D: Long Answer Questions (3 marks each)

1. Describe the four whorls of a flower in detail, including their structure and functions. A typical flower has four whorls arranged on the receptacle.

   1. Calyx: The outermost whorl, composed of green, leaf-like sepals. Its primary function is to protect the flower during its bud stage.
   2. Corolla: The whorl inside the calyx, composed of often brightly colored petals. Its main function is to attract pollinators like insects and birds through its color, scent, and nectar guides.
   3. Androecium: The male reproductive part, consisting of stamens. Each stamen has a filament (stalk) and an anther (sac) that produces and contains pollen grains, which hold the male gametes.
   4. Gynoecium: The innermost, female reproductive part, consisting of one or more carpels (pistil). Each carpel has a stigma (receives pollen), a style (connects stigma to ovary), and an ovary (contains ovules). Its function is to produce the female gametes within ovules and to house the developing seeds after fertilization.

2. Explain the different types of pollination and describe the adaptations of flowers for each type. Pollination is the transfer of pollen from anther to stigma. There are two main types:

   • Self-Pollination: Pollen is transferred within the same flower or to another flower on the same plant. Flowers adapted for this are often small and may not have prominent attractive features.
   • Cross-Pollination: Pollen is transferred from one plant to another of the same species. This requires external agents, and flowers show specific adaptations:
     • Wind Pollination (Anemophily): Flowers are small, dull, and lack nectar/scent. They produce huge amounts of light, dry pollen and have large, feathery stigmas (e.g., Maize).
     • Insect Pollination (Entomophily): Flowers are large, colorful, fragrant, and produce nectar to attract insects. Pollen is sticky or spiny to adhere to insects (e.g., Rose).
     • Water Pollination (Hydrophily): Flowers are small and inconspicuous. Pollen is light and unwettable to be carried by water (e.g., Vallisneria).

3. Describe the complete process of fertilization in flowering plants, from pollination to zygote formation. The process begins with pollination, where a pollen grain lands on the receptive stigma of a compatible flower. The pollen grain then absorbs moisture and germinates, growing a thin pollen tube. This tube grows down through the style, guided by chemical signals, towards the ovary. Inside the pollen grain are two male gametes. These gametes travel down the pollen tube, which eventually penetrates an ovule within the ovary. Finally, fertilization occurs when one of the male gametes fuses with the female gamete (egg cell) inside the ovule. This fusion results in the formation of a diploid zygote, which is the first cell of the new embryo.

4. Explain the formation of fruits and seeds after fertilization, describing the changes in different flower parts. After fertilization is complete, the flower undergoes significant transformation to produce fruits and seeds.

   • Ovary to Fruit: The primary change is the development of the ovary into the fruit. The wall of the ovary thickens and differentiates to become the pericarp (the wall of the fruit), which may be fleshy or dry.
   • Ovules to Seeds: The ovules contained within the ovary develop into seeds. The fertilized egg inside the ovule grows into the embryo, and the ovule walls harden to form the protective seed coat.
   • Other Floral Parts: The remaining parts of the flower, which have served their purpose, wither and fall off. This includes the petals, sepals, stamens, stigma, and style. Their nutrients are often reabsorbed by the plant to support the growing fruit and seeds.

5. Compare and contrast the characteristics of wind-pollinated and insect-pollinated flowers with suitable examples. Contrast:

   • Attractants: Insect-pollinated flowers are large, colorful, and scented to attract pollinators (e.g., Sunflower), while wind-pollinated flowers are small, dull, and unscented as they don't need to attract animals (e.g., Grasses).
   • Pollen: Insect-pollinated flowers produce smaller amounts of large, sticky/spiny pollen. Wind-pollinated flowers produce vast quantities of small, light, dry pollen.
   • Stigma: Insect-pollinated flowers have sticky stigmas to receive pollen from insects. Wind-pollinated flowers have large, feathery stigmas to trap airborne pollen.
   • Nectar: Nectar is present in insect-pollinated flowers as a reward but absent in wind-pollinated ones. Comparison:
   • Both are mechanisms of cross-pollination designed to transfer pollen from the anther of one flower to the stigma of another, ensuring sexual reproduction.

6. Describe the structure of a seed and explain the process of germination with necessary conditions. A seed is a fertilized ovule containing an embryo and stored food, protected by a seed coat. Its main parts are the seed coat (outer protection), the embryo (miniature plant with a radicle/embryonic root and plumule/embryonic shoot), and cotyledons (seed leaves that store food). Germination is the process where the embryo sprouts into a seedling. For this to occur, three conditions are necessary:

   1. Moisture (Water): It softens the seed coat and activates enzymes that break down stored food.
   2. Warmth (Suitable Temperature): Enzymes function best at an optimal temperature, allowing metabolic processes to occur.
   3. Air (Oxygen): Oxygen is required for aerobic respiration, which releases the energy needed for the embryo to grow and emerge from the seed.

7. Explain the different types of seed germination with examples and describe what happens during each type. There are two main types of seed germination based on the fate of the cotyledons.

   1. Epigeal Germination: In this type, the hypocotyl (the stem part below the cotyledons) elongates rapidly, pushing the cotyledons and the plumule above the soil surface. The cotyledons may then turn green and photosynthesize before withering. An example is the Bean seed.
   2. Hypogeal Germination: In this type, the epicotyl (the stem part above the cotyledons) elongates, while the cotyledons remain below the soil surface. The cotyledons serve only as a food source and do not emerge from the ground. An example is the Maize seed.

8. Describe the structure and classification of fruits, explaining the significance of different fruit types. A fruit is a mature, ripened ovary that encloses the seed or seeds. Its wall, the pericarp, has three layers: the outer epicarp, middle mesocarp, and inner endocarp. Fruits are broadly classified into:

   • Fleshy Fruits: The pericarp is thick and juicy at maturity. They are significant because their fleshy nature attracts animals, which eat them and help in seed dispersal over long distances. Examples include Mango and Tomato.
   • Dry Fruits: The pericarp is dry and hard at maturity. Their significance lies in protection and varied dispersal mechanisms. Some split open to release seeds (e.g., Pea pod), while others are adapted for dispersal by wind or other means (e.g., Groundnut, Wheat).

9. Explain the agents of cross-pollination and describe the adaptations of flowers for each agent. Cross-pollination relies on external agents to move pollen between plants.

   1. Wind (Anemophily): Flowers are adapted by being small, inconspicuous, and lacking attractants. They produce enormous amounts of light, dry pollen and have large, feathery stigmas to catch it (e.g., Pine, Grasses).
   2. Insects (Entomophily): Flowers are adapted to attract insects with large, colorful petals, fragrance, and nectar. They produce sticky pollen that adheres to the insect's body and have sticky stigmas to receive it (e.g., Hibiscus, Pea).
   3. Water (Hydrophily): This is rare and occurs in aquatic plants. Flowers are small, and the pollen is light and protected from water by a waxy coating, allowing it to float to other flowers (e.g., Hydrilla, Vallisneria).

10. Describe the male and female reproductive parts of a flower and explain their roles in reproduction.

    • Male Reproductive Part (Androecium): This whorl is composed of stamens. Each stamen consists of a slender filament that holds up an anther. The role of the anther is crucial: it produces and stores pollen grains. Each pollen grain contains the male gametes necessary for fertilization. The filament's role is to position the anther effectively for pollen dispersal.
    • Female Reproductive Part (Gynoecium): This is the central whorl, composed of one or more carpels (or a pistil). It has three parts. The stigma is the receptive tip, whose role is to trap pollen. The style is a stalk that connects the stigma to the ovary, providing a path for the pollen tube. The ovary is the swollen base that contains ovules. The ovules house the female gamete (egg cell), and after fertilization, they develop into seeds.

11. Explain how the structure of wind-pollinated flowers is adapted to their mode of pollination, giving specific examples. Wind-pollinated flowers are highly specialized for inefficient, random pollen dispersal by wind.

    • Inconspicuous Flowers: They are typically small, dull-colored (often green or brown), and lack petals, scent, and nectar because they do not need to attract animal pollinators. Example: Grasses.
    • Pollen Production: They produce pollen in enormous quantities to increase the probability that some will land on a suitable stigma. The pollen grains are very small, light, and dry, allowing them to be carried long distances by the wind. Example: Pine trees releasing clouds of yellow pollen.
    • Exposed Stamens and Stigmas: The stamens often have long filaments that hang outside the flower, exposing the anthers to the wind. The stigmas are large, feathery, and branched to create a large surface area for trapping airborne pollen. Example: Maize with its long, silky stigmas (silks).

12. Describe the journey from pollination to seed formation, explaining each step in detail. The journey involves several key stages:

    1. Pollination: Pollen from an anther is transferred to a compatible stigma by an agent like wind or insects.
    2. Pollen Germination: The pollen grain forms a pollen tube that grows down through the style towards the ovary.
    3. Fertilization: The pollen tube reaches an ovule, and a male gamete fuses with the female egg cell to form a zygote.
    4. Embryo Development: The zygote divides and develops into an embryo, which consists of a radicle, plumule, and cotyledons.
    5. Seed Development: The entire ovule matures into a seed. The outer layers of the ovule harden to become the protective seed coat, and nutritive tissue (like endosperm) develops.
    6. Fruit Development: Simultaneously, the ovary containing the ovules matures into a fruit, which encloses and protects the newly formed seeds.

13. Compare monocotyledonous and dicotyledonous seeds in terms of structure, germination, and examples.

    • Structure: The most fundamental difference is the number of cotyledons. Monocot seeds have one cotyledon (e.g., Maize, Rice), while Dicot seeds have two (e.g., Bean, Gram). In monocots, food is stored in the endosperm, whereas in dicots, it is typically stored in the fleshy cotyledons themselves.
    • Germination: Monocots usually exhibit hypogeal germination, where the cotyledon remains underground, and the plumule is protected by a sheath as it emerges. Dicots often exhibit epigeal germination, where the two cotyledons are pushed above ground by the growing hypocotyl and may even photosynthesize for a short time.
    • Embryo: The basic structure of the embryo (radicle and plumule) is similar, but in monocots, it is often located to one side of the endosperm.

14. Explain the importance of different environmental conditions for seed germination and describe what happens if any condition is absent. The three critical conditions for germination are water, warmth, and oxygen.

    • Water (Moisture): Its presence is crucial for rehydrating the dry seed tissues, which activates enzymes and softens the seed coat for the radicle to emerge. If absent, the seed remains dormant as metabolic activity cannot begin.
    • Warmth (Suitable Temperature): Temperature controls the rate of enzyme activity and metabolic reactions. Each seed has an optimal range. If it is too cold or too hot, enzymes will not function properly, and germination will fail or be severely stunted.
    • Oxygen (Air): Oxygen is essential for aerobic respiration, the process that breaks down stored food to release the large amount of energy required for the embryo's growth. If absent (e.g., in waterlogged soil), the seed cannot produce enough energy and will fail to germinate or die.

15. Describe the structure of different types of fruits and explain how each type helps in seed protection and dispersal. Fruit structure is closely related to its function in seed protection and dispersal.

    • Fleshy Fruits (e.g., Mango, Tomato): These have a soft, juicy pericarp that is attractive to animals. Animals eat the fruit, and the tough seeds pass through their digestive tract unharmed, being dispersed far from the parent plant. The hard endocarp in fruits like mangoes provides extra protection to the seed.
    • Dry Dehiscent Fruits (e.g., Pea pod): These have a dry pericarp that splits open when mature, often forcefully scattering the seeds away from the plant. This mechanism avoids overcrowding.
    • Dry Indehiscent Fruits (e.g., Sunflower, Wheat): These dry fruits do not split open. They rely on other methods for dispersal. For example, a sunflower seed (which is actually a fruit) is often eaten by birds, while wheat grains are dispersed by humans. Some dry fruits have wings or plumes to be carried by the wind.

16. Explain the process of cross-pollination by insects, describing the adaptations of both flowers and insects. Cross-pollination by insects (entomophily) is a co-evolved relationship.

    • Flower Adaptations: Flowers attract insects using various signals. Visual cues include large, brightly colored petals (e.g., yellow, blue, which insects see well). Olfactory cues include sweet fragrances. As a reward, flowers provide nectar, a sugary liquid. The flower's structure is often shaped to ensure the insect makes contact with the anthers and stigma. The pollen is sticky or spiny, and the stigma is sticky to facilitate pollen transfer.
    • Insect Adaptations: Insects like bees have body parts (e.g., hairy legs) that are well-suited for picking up pollen. They have good vision and a strong sense of smell to locate flowers. They visit flowers to collect nectar for food, and in the process, they unintentionally transfer pollen from one flower to another, thus acting as couriers for the plant's reproduction.

17. Describe the formation and structure of the embryo, explaining the development from zygote to mature embryo. The formation of the embryo begins immediately after fertilization. The zygote, which is a single diploid cell, undergoes a series of mitotic cell divisions to grow into a multicellular structure. This process is called embryogenesis. Initially, the zygote divides to form a small group of cells. As development continues, these cells differentiate to form the basic structures of the mature embryo. The mature embryo is essentially a miniature plant, consisting of:

    • An embryonic axis, which has two ends.
    • The radicle, or embryonic root, which is at one end of the axis and is the first part to emerge during germination to form the root system.
    • The plumule, or embryonic shoot, which is at the other end and will develop into the stem and leaves.
    • One or two cotyledons (seed leaves), which are attached to the embryonic axis and serve as a food source.

18. Explain the advantages and disadvantages of self-pollination and cross-pollination with suitable examples.

    • Self-Pollination (e.g., Pea plants):
      • Advantages: It is a reliable and efficient method of reproduction as it does not depend on external agents. It preserves desirable parental traits, which is useful in agriculture. Less pollen needs to be produced.
      • Disadvantages: It leads to a lack of genetic variation, making the population more vulnerable to diseases and environmental changes. Continuous self-pollination can lead to a loss of vigor and vitality over generations.
    • Cross-Pollination (e.g., Roses, Sunflowers):
      • Advantages: The primary advantage is the creation of genetic diversity in offspring, which increases the species' ability to adapt to changing conditions and can lead to healthier, more vigorous plants.
      • Disadvantages: It is less certain as it depends on external agents like wind or insects, which may not be available. The plant must expend more energy producing large amounts of pollen and attractive features like large petals and nectar.

19. Describe the complete life cycle of a flowering plant from pollination to germination of the next generation. The life cycle of a flowering plant is a continuous loop of reproduction and growth.

    1. Pollination: The cycle begins with the transfer of pollen from an anther to a stigma.
    2. Fertilization: A male gamete from the pollen grain fuses with the female gamete in an ovule, forming a zygote.
    3. Fruit and Seed Development: The zygote develops into an embryo, the ovule becomes a seed, and the ovary ripens into a fruit that encloses the seed(s).
    4. Seed Dispersal: The mature fruit facilitates the dispersal of seeds away from the parent plant, carried by wind, water, or animals.
    5. Dormancy: The seed may remain dormant until conditions are favorable.
    6. Germination: When conditions (water, warmth, oxygen) are right, the seed germinates. The radicle emerges to form the root, and the plumule grows to form the shoot.
    7. Growth and Maturation: The seedling grows into a mature plant, developing roots, a stem, leaves, and eventually, its own flowers, at which point the cycle can begin again.

20. Explain the structural adaptations of water-pollinated flowers and compare them with wind and insect-pollinated flowers. Water-pollinated (Hydrophilous) Flowers:

    • Structure: These flowers are generally small, inconspicuous, and lack bright colors, scent, or nectar. Their key adaptation is related to the pollen. The pollen grains are often light and have a waterproof, unwettable coating that prevents them from getting waterlogged, allowing them to float. In some species like Vallisneria, the male flowers detach and float to the female flowers. Comparison:
    • vs. Wind-pollinated: Both are pollinated by abiotic agents and thus lack features to attract animals. However, wind-pollinated flowers produce vast amounts of dry, dust-like pollen, while water-pollinated flowers produce unwettable pollen, often in smaller quantities.
    • vs. Insect-pollinated: They are opposites in almost every way. Insect-pollinated flowers are large, showy, and produce nectar and sticky pollen to interact with animals. Water-pollinated flowers are stripped of all these features as they are unnecessary and would be a waste of energy.

21. Describe the process of fruit development from flower, explaining the fate of each floral part. Fruit development is initiated by hormones released after successful fertilization.

    • Ovary: This is the primary part that develops into the fruit. The wall of the ovary thickens and matures into the pericarp. The ovary grows significantly in size as food reserves are mobilized to it.
    • Ovules: The ovules inside the ovary develop into the seeds.
    • Fate of Other Parts:
      • Stigma and Style: Having served their function of receiving pollen and guiding the pollen tube, they wither and fall off.
      • Petals: Their role in attracting pollinators is over, so they wither and drop.
      • Stamens: Their pollen has been shed, so they also wither and fall away.
      • Sepals: In most plants, the sepals also wither and fall off. However, in some cases (like in a tomato or brinjal), they may persist and remain attached to the base of the fruit. Essentially, the flower transforms from a reproductive structure into a vessel for protecting and dispersing the next generation (the seeds).

22. Explain the role of environmental factors in pollination and describe how different pollinators are attracted to flowers. Environmental factors play a key role in pollination success. Wind speed and direction are critical for anemophily. Rain can wash away pollen and deter flying insects, hindering both wind and insect pollination. Temperature affects the activity of insect pollinators, as most are less active in cold weather. Different pollinators are attracted by specific floral signals:

    • Bees are attracted to bright blue and yellow flowers, often with sweet scents and nectar guides (patterns visible in UV light).
    • Birds, like hummingbirds, are attracted to red, orange, or white tubular flowers that produce large amounts of thin nectar. They have poor sense of smell, so these flowers are often odorless.
    • Moths and Bats are active at night, so they are attracted to large, white or pale-colored flowers that are heavily fragrant and open in the evening or at night.

23. Describe the internal structure of a seed and explain how each part contributes to the development of a new plant. A seed is a self-contained unit for plant reproduction. Its internal structure consists of:

    1. Embryo: This is the core component, the miniature plant itself.
       • Radicle: The embryonic root. During germination, it is the first part to emerge, growing downwards to anchor the seedling and absorb water and nutrients from the soil.
       • Plumule: The embryonic shoot. It grows upwards, developing into the stem and leaves, which will eventually perform photosynthesis.
       • Cotyledon(s): The seed leaves. Their critical role is to provide the initial energy for germination by storing food (as in dicots like beans) or by transferring food from the endosperm to the embryo (as in monocots like maize).
    2. Stored Food: This nutritive tissue (either in the cotyledons or as endosperm) fuels the embryo's growth until the seedling can produce its own food.
    3. Seed Coat: This tough outer layer protects the delicate embryo and its food supply from physical damage, pests, and drying out.

24. Explain the significance of sexual reproduction in flowering plants and describe the mechanisms that ensure genetic diversity. The primary significance of sexual reproduction is the creation of genetic variation in offspring. This is vital for the adaptation and long-term survival of a species, allowing it to cope with changing environments, diseases, and pests. A genetically diverse population is more resilient than a uniform one. Flowering plants have several mechanisms to ensure genetic diversity, primarily by promoting cross-pollination:

    • Bisexual Flowers with Differential Maturation: In some flowers, the male and female parts mature at different times, preventing self-pollination.
    • Structural Barriers: The physical arrangement of the stigma and anthers in some flowers makes self-pollination difficult or impossible.
    • Self-Incompatibility: Many plants have a genetic mechanism that allows them to recognize and reject their own pollen, preventing fertilization from occurring after self-pollination.
    • Production of Unisexual Flowers: Some plants produce separate male and female flowers, either on the same plant or on different plants, which necessitates cross-pollination.

25. Describe the different methods of seed dispersal and explain how fruit structure is related to the method of dispersal. Seed dispersal is the movement of seeds away from the parent plant, which is crucial to reduce competition. The structure of the fruit is highly adapted for its dispersal method.

    • Wind Dispersal (Anemochory): Fruits are typically lightweight and have structures to catch the wind. Examples include the "wings" on maple fruits or the feathery plumes on dandelion fruits (which are achenes).
    • Animal Dispersal (Zoochory):
      • Via Ingestion: Fleshy, sweet, and brightly colored fruits (e.g., berries, mangoes) are eaten by animals. The seeds are tough enough to survive digestion and are deposited in the animal's droppings elsewhere.
      • Via Attachment: Some fruits have hooks, barbs, or spines (e.g., burrs) that attach to the fur of passing animals and are carried away.
    • Water Dispersal (Hydrochory): Fruits of aquatic or coastal plants (e.g., coconut) are buoyant and have a waterproof pericarp, allowing them to float for long periods to new locations.
    • Mechanical (Self) Dispersal: Some dry fruits (e.g., pea pods) are structured to dry out and twist, splitting open explosively to fling the seeds away from the parent.