Reproduction in Plants : 12th Class Biology Question Answer Lesson 19 – NIOS

Reproduction in Plants : 12th Class Biology Question Answer Lesson 19 – NIOS

Reproduction in Plants : 12th Class Biology Question Answer Lesson 19 - NIOS


  1. Define reproduction.
    Ans. The process by which living organisms produce their offsprings for the continuity of the species.
  2. How is asexual reproduction different from sexual reproduction?
    Ans. Offsprings reproduce from a vegetative unit produced by a parent
    without fusion of gamete. In case of sexual reproduction fusion of male
    and female reproductive cells produced in male and female reproductive organs, is required.

  3. What is a gamete?
    Ans. Male and female reproductive cells are known as gametes.
  4. Name two types of vegetative reproduction.
    Ans. Fission, budding, fragmentation.
  5. Choose the correct option
    Apomixis is:
    (a) Development of plants in darkness
    (b) Development of plants without fusion of gametes
    (c) Inability to perceive stimulus for flowering
    (d) Effect of low temperature on plant growth
    Ans. b


  1. Define the term isogamy. Which species of Chlamydomonas exhibits isogamy.
    Ans. Male and female gametes are identical in structure.
  2. Where does meiosis occur in Chlamydomonas ?- Zygote
  3. Give the method of asexual reproduction in Chlamydomonas. What is the function of zoospores in Chlamydomonas.- Asexual reproduction
  4. Name the speicies of Chlamydomonas that reproduces by Anisogamy and the species that reproduces by Oogamy.
    Ans. Anisogamy – C. braunii;
    Oogamy – C.oogamum and C. coccifera
  5. Define the term zoospore and aplanospore.
    Ans. A flagellate thin-walled asexual reproductive unit is called zoospore. If
    a zoospore loses flagella and becomes, non motile, it is called aplanospore


  1. Vegetative reproduction in Spirogyra takes place by means of
    Ans. Fragmentation
  2. Name the kind of sexual reproduction that occurs in Spirogyra.
    Ans. Scalariform Conjugation.
  3. When does meiosis occur in Spirogyra ?
    Ans. Diploid nucleus in zygote on return of favourable conditions.
  4. How many filaments are involved in lateral conjugation ?
    Ans. Only one filament is involved in lateral conjugation


  1. Define the terms (i) Annual (ii) Biennial (iii) Perennial
    Ans. Annual – Plants which produce flowers and seeds and die within one
    Biennial – Plants which complete their life cycle in two seasons. In First season they are in vegetative state and in second season, they reproduce and die.
    Perennial – Plants which live for several years. For first few years they are in vegetative state and later, they flower and produce fruits and seeds every year.
  2. List the factors which induce flowering
    Ans. Temperature, light – day length
  3. Give one example where external application of hormone can reverse the sex of a flower
    Ans. Cannabis or Cucumis
  4. Name the essential whorls in a flower.
    Ans. Stamens and Carpels


  1. What is the innermost wall layer of microsporangium called? – Tapetum
  2. Name the organ where pollen grains are formed. Heredity – Pollen sac
  3. Name the two layers of pollen grain –  Exine and intine
  4. Name two parts of a mature ovule.
    Ans. Nucellus and integuments


  1. What is pollination?
    Ans. Transfer of pollen grains from anther to stigma of a flower.
  2. Mention suitable terms for the following :
    (i) Flowers do not open and get self-pollinated. – Cleistogamy
    (ii) Male and female reproductive organs mature at different times. – Dichogamy
  3. Give two features of insect pollinated flowers :
    (i) Flowers are large, coloured and showy
    (ii) Some flowers secrete nectar.


  1. Which part of the ovule forms the seed coat ? – Integuments.
  2. Define a seed. – Ripened ovule.
  3. Give one example of a dicot seed and one of a monocot seed. – Pea or Gram, Maize grain.
  4. Define a fruit.
    Ans. Ripened ovary.
    Seed coat

  5. List the parts of mature seed.
    Ans. Embryo

  6. Development of an embryo from a cell of embryo sac other than egg is an example of – Adventive Polyembryony
  7. Formation of more than one embryo from a single zygote is called – Cleavage Polyembryony


  1. Define vegetative reproduction.
    Ans.The process of multiplication in which a portion of the plant body
    becomes detached and develops into new plants.

  2. Give an example of each of the following :
    (a) rhizome – ginger
    (b) tuber – potato
    (c) bulb – onion
    (d) runner – Lawn grass
    (e) sucker – mint
  3. Give an example of vegetative reproduction which is carried out by leaves.
    Ans. Bryophyllum
  4. Name two ways by which vegetative reproduction occurs in plants.
    Ans. Rhizomes and Bulbs


  1. What are the various methods which man uses for propagating plants artificially?
    Ans. Cutting (b) Grafting (c) Layering
  2. Name at least four specialised plant parts which help in vegetative, propagation.
    Ans. (a) Runner (b) Tuber (c) Bulb (d) Sucker
  3. Write one advantage of vegetative reproduction.
    Ans. Desirable varieties of ornamental plants and fruit trees can be multiplied easily.


  1. Give two examples each of plants which are propagated by the following methods:
    (a) Cutting – (i) Croton (ii) Money plant
    (b) Layering – (i) Jasmine (ii) Grapevine
    (c) Grafting – (i) Rose (ii) Mango
  2. Name the artificial means of vegetative propagation commonly used in the laboratory. – Micropropagation
  3. Give two examples of plants which are propagated by micropropagation
    Ans. Orchids, Chrysanthemum, Asparagus.


  1. Explain the term isogamy taking Chlamydomonas as an example.
  2. Describe scalariform conjugation in Spirogyra.
  3. Differentiate between annuals, biennials and perennial plants.
  4. Give significance of pollination.
  5. Draw a labelled sketch of a mature ovule.
  6. Give a labelled diagram of a mature pollen grain.
  7. Mention important characteristics in Anemophilous and Hydrophilous plants.
  8. Give the significance of fertilisation.
  9. Mention the changes that take place when the fruit ripens.
  10. Define the following terms :
    (a) Corm (b) Scion
    (c) Callus (d) Micropropagation
    (e) Vegetative reproduction
  11. In what ways do plants reproduce vegetatively without human assistance ?
  12. In what ways do plants reproduce vegetatively with human assistance?
  13. Define and give an example of each of the following:
    (a) Rhizome (b) Stolon (c) Cutting
    (d) Layering (e) Grafting
  14. What are the advantages and disadvantages of vegetative reproduction ?
  15. In what way is vegetative reproduction simple ?
  16. Write short notes on
    (a) Runner (b) Sucker (c) Bulb (d) Tuber
  17. In brief describe the various steps of micropropagation.
  18. What is the significance of micropropagation ?
  19. If a branch of dasehri mango is grafted on a tree producing desi mango. What type of mangoes will be produced on the grafted branch and on other branches of the tree?

NIOS 12th class biology Q Ans

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