NCERT Class 7 Science Chapter 12 - Reproduction in Plants

Chapter 12 - Reproduction in Plants

Question and Answers
Question 1: Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called vegetative propagation.
(b) A flower may have either male or female reproductive parts. Such a flower is called Unisexual.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as pollination.
(d) The fusion of male and female gametes is termed as fertilisation.
(e) Seed dispersal takes place by means of wind, water and animals.
 
Question 2: Describe the different methods of asexual reproduction. Give examples.
Answer: Different methods of asexual production are:
Vegetative propagation: It is a process by which new plants are produced from roots, stem, leaves and buds. Example: Rose

Budding: The process in which small-bulb like projection come out from a cell and get detached is called budding. Example: Yeast

Spore formation: Spore formation is a method of asexual reproduction. Spores are stored in sacs called sporangium. Under favourable conditions, a spore germinates and develops into a new individual. Example: Fungus

Fragmentation: It is a process in which cells further split into 2 or more fragments is called fragmentation. Example: Spirogyra
 
Question 3: Explain what you understand by sexual reproduction.
Answer: Sexual reproduction is a method where male and female gametes fuse to form a new individual. In plants, stamen and pistils are male and female reproductive organs which bear the anthers and ovary respectively.
 
 
Question 4: State the main difference between asexual and sexual reproduction.
Answer: Asexual reproduction
*It requires only one parent.
*Daughter cells are formed are identical to parents and to each other.
*Special reproductive organs are not required. Example: yeast, rose

Sexual reproduction
*Requires a male and female parent.
*Newly formed offspring show variations in comparison to the parents.
*Special reproductive organs are required. Example: insect, animals
 
Question 5: Explain the difference between self-pollination and cross-pollination.
Answer: Self pollination
*It involves the transfer of pollen from the stamen to the pistil of the same flower.
*Self-pollination occurs in bi-sexual flowers.

Cross pollination
*It involves the transfer of pollen from the stamen of one flower to the pistil of another flower.
*It occurs in both unisexual and bisexual flowers.
 
Question 6: How does the process of fertilization take place in flowers?
Answer: The process of fusion of male and female gametes (to form zygotes) is called fertilization. The zygote develops into an embryo and embryo undergoes mitotic cell division to form seeds.

Question 7: Describe the various ways by which seeds are dispersed.
Answer: Seeds and fruits of plants are carried away by the wind, water and animals. Winged seeds such as those of drumstick and maple, light seeds of grasses and hairy seeds of aak and hairy fruits of sunflower, get blown off with the wind to faraway places. Some seeds are dispersed by water. These fruits or seeds usually develop floating ability in the form of spongy or fibrous outer coat as in coconut. Some seeds are dispersed by animals specially Xanthium and Urena. Some seeds are dispersed when the fruits burst with sudden jerks. The seeds are scattered far from the parent plant. This happens in case of plants castor and balsam.

Question 8: Answer the following questions in one word
(a) The reproductive part of a plant is the
Answer: Flower

(b) The process of fusion of the male and the female gametes is called
Answer: Fertilisation  

(c) Mature ovary forms the
Answer: Fruit

(d) A spore producing organism is
Answer: Bread mould

(e) Bryophyllum can reproduce by its
Answer: Leaves