12th Lesson 1 Two mark question answer

1. Write two major categories of reproduction

Two major categories of reproduction are

1. Asexual reproduction 2. Sexual reproduction.

2. Define asexual reproduction

The reproduction takes place without the

involvement of gametes and helps to perpetuate

its own species is called asexual reproduction.

3. How does Penicillium and Aspergillus 

reproduce Asexually ?

Penicillium and Aspergillus reproduce Asexually byth formation of Conidia

4. What is reproductive propagules ?

The unit of reproductive structure used in

propagation is called reproductive propagules or


5. Write the disadvantage of natural vegetative 


New plants produced have no genetic variation.

6. What is artificial propagation ?

A number of Artificial methods are used in

agriculture and horticulture to propagate plants

from their parts. Such methods are said to be

artificial propagation.

7. What is modern methods propagation of 


Many technology is used for propagation to

produce large number of plants in a short period

of time. Such methods are called modern methods.

8. Define tissue culture.

The growth of plant tissue in special culture

medium under suitable controlled conditions is

known as tissue culture.

9. What is Micropropagation?

The regeneration of a whole plant from single

cell, tissue or small pieces of vegetative structures

through tissue culture is called micropropagation.

10. Deine Sexual reproduction.

Male and female gametes fuse together to form a

diploid zygote that grows into a new individual are called Sexual reproduction.

11. What is gametogenesis and fertilization ?

The production of male and female gametes are

called gametogenesis and the fusion of male and

female gametes are called fertilization.

12. What is microsporogenesis ?

The formation of haploid microspores (n) from

diploid microspore mother cell (2n) by meiosis is

called Microsporogenesis.

13. Describe pollinium.

All microspores in a microsporangium remain heldt together called pollinium. Example: Calotropis.

14. What is corpusculum ?

Pollinia are attached to a clamp or clip like sticky

structure called corpusculum.

15. What is retinaculum ?

The filamentous or thread like part arising from

each pollinium is called retinaculum.

16. Describe translator.

The whole structure of pollinium looks like inverted letter ‘Y’ and is called translator.

17. What is mellitopalynology ?


18. What is megasporangium ?

Ovule is also called megasporangium.

19. What is integuments ?

ovule is protected by one or two covering called


20. What is funiculus ?

A mature ovule consists of a stalk called funiculus 


21. What is funiculus hilum ?

The point of attachment of funicle to the body of

the ovule is known as hilum.

22. What is raphe ?

The funicle is adnate to the body of the ovule

forming a ridge called raphe.

23. What is nucellus ?

The body of the ovule is made up of a central

mass of parenchymatous tissue called nucellus.

24. What is micropyle ?

Integument encloses the nucellus except at the

top and forms a pore called micropyle.

25. Unitegmic and bitegmic differentiate.

The ovule with one integument said to be

unitegmic or two integuments are said to be


26. What is chalaza ?

The nucellus, the integument and the funicle

meet at the basal region of the ovule is called as


27. What is an embryo sac ?

The micropylar end of the nucellus contains large

oval, sac-like structure called embryo sac or

female gametophyte

28. What is stomium ?

The cells along the junction of the two sporangia

of an anther lobe lack these thickenings.

This region is called stomium.

29. What is hypostase ?

Group of cells found at the base of the ovule

between the chalaza and embryo sac is called


30. What is epistase ?

The thick -walled cells found above the micropylar end above the embryo sac is called epistase

31. What is bisporic embryo sac ?

Out of four megaspores, two are involved in

Embryo sac formation.

This development is called bisporic. Example:  Allium.

32. What is tetrasporic embryo sac ? give an 


All the four megaspores are involved in Embryo

sac formation.

This development is called tetrasporic.

Example: Peperomia.

33. What is synergids ?

In egg apparatus of embryo sac, one on each side

of the egg cell are called synergids.

It secrete chemotropic substances that help to

attract the pollen tube.

34. Define pollination.

Transfer of pollen grains from the anther to a

stigma of a flower is called pollination.

35. Classify the types of pollination.

Pollination is classified into self-pollination 

(Autogamy) and cross-pollination(Allogamy)

36. Descrbe self-pollination or autogamy. In what 

type of flowers it is possible.

The transfer of pollen on the stigma of the

same flower is called self-pollination or 


It is possible only in bisexual flowers.

37. Define Cross - pollination.

The transfer of pollens on the stigma of another

flower is called cross-pollination.

38. What is Xenogamy ?

Genetically different pollen deposits on another

flower of a different plant of the same species is

called as xenogamy.

39. Define mellitopalynology.


40. Describe zoophilous flowers.

Pollination by animals is called zoophily and flowers

are said to be zoophilous.

41. Name the animal pollinators.

Animal pollinators are birds, bats, snails, insects,

Larger animals like primates (lemurs), arboreal

rodents, reptiles (gecko lizard and garden


42. What is entomophily ?

Pollination by insects is called Entomophily.

43. What is myrmecophily ?

Pollination by ant is called myrmecophily.

44. What is cantharophily ?

Pollination by Beetle is called Cantharophily

45. What is Phalaenophily ?

Pollination by Moths is called Phalaenophily

46. What is Mellitophily ?

Pollination by Bees is called Mellitophily

47. What is Psychophily ?

Pollination by Butter flies is called Psychophily

48. What is Malacophily ?

Pollination by Snails is called Malacophily

49. What is Ornithophily ?

Pollination by Birds is called Ornithophily

50. What is Chieropterophily ?

Pollination by Bats is called Chieropterophily

51. What is Myrmecophily ?

Pollination by Ants is called Myrmecophily

52. Name some Insects pollinators

Insects pollinators are bees, moths, butterflies,

flies, wasps and beetles.

53. Which is the dominant pollinators of flowers ?

Bees are the main flower visitors and dominant


54. Which are the chief pollinating agents of 

angiosperms ?

Insects are chief pollinating agents and majority

of angiosperms are adapted for insect pollination.

55. Which type of pollination is most common 

type of pollination ?

Entomophily is the most common type of


56. Describe ornithophily.

Pollination by birds is called Ornithophily.

57. Name the plants pollinated by birds ?

The plants pollinated by birds are Erythrina,

Bombax, Syzygium, Bignonia, Sterlitzia etc.,

58. Name some of the birds which regularly visit 

flowers and bring about pollination.

Humming birds, sun birds, and honey eaters

are some of the birds which regularly visit

flowers and bring about pollination.

59. What is fertilization ?

The fusion of male and female gamete is called


60. What is pollen- pistil interaction ?

To the entry of pollen tube in to the ovule is

called pollen- pistil interaction.

61. Define cheiropterophily ? Give examples.

Pollination by bats is called cheiropterophily.

Example : Kigelia africana, Adansonia digitata,


62. Write the disadvantages of self-pollination

Continuous self-pollination, produce weaker


Less chances of producing new species and


63. What is Porogamy?

The pollen tube enters through the micropyle

called Porogamy.

64. What is Chalazogamy?

The pollen tube enters through the chalaza called


65. What is Mesogamy ?

The pollen tube enters through the integument

called Mesogamy.

66. Define syngamy

One male gametes (n) fuses with the egg (n) to

form zygote (2n) is called syngamy

67. What is caruncle ? Give an example.

The cells present at the tip of the outer integument

around the micropyle develop into a fleshy

structure called caruncle. Ex. Ricinus communis.

68. What is aril ? Give examples.

The funiculus develops into a fleshy structure

which is often very colourful and called aril. Ex.

Myristica and Pithecellobium

69. What is Ruminate endosperm ?


in its surface forms ruminate endosperm.

Examples :Areca catechu, Passiflora and Myristica

70. Define endosperm

The primary endosperm nucleus (PEN) divides

immediately after fertilization form a structure

is called endosperm

71. Name the three types of endosperm in 


1. nuclear endosperm, 2. cellular endosperm and

3. helobial endosperm

72. Define Caryopsis ?

The seed of paddy is one seeded and is called


73. What is coleoptile ?

In monocot seed, the radicle including root cap

is also covered by a protective sheath called


74. What is amphimixis ?

Reproduction involving fertilization in flowering

plants is called amphimixis

75. Describe recurrent apomixis

It includes vegetative reproduction and


76. Describe non recurrent apomixis.

Haploid embryo sac developed after meiosis,

develops into an embryo without fertilization.

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