EVENTS CONVENT H.SCHOOL
05/02/2021
CLASS-7 SLOT-2
Science
Chapter-12 Reproduction
in Plant
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(a) Production of new individuals from the vegetative part
of parent is called vegetative reproduction
(b) A flower may have either male or female reproductive
parts. Such a flower is called unisexual flower
(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 fertilization
(e) Seed dispersal takes place by means of wind and
water.
Q.2. Describe the different methods
of asexual reproduction. Give examples.
Ans. Different methods of asexual reproduction are:
(a) Binary Fission: This process takes place in unicellular
organisms. Parent cell elongates and gets divided into two identical daughter
cells. Each daughter cell grows into an independent adult.
(b) Endospore Formation: In this method the spore wall is
formed around a bacterial cell to form an endospore. This endospore germinates
to form an active bacterium under favourable conditions.
(c) Fragmentation: In this process, body of the organism
breaks up into two parts. Then each part grows into a new filament thus forming
two organisms from a single one.
(d) Budding: In
yeast, new organisms are produced by the bud formation from the parent
organism. After growing to full size, the bud gets detached and forms a new
independent individual.
(e) Vegetative propagation: When vegetative parts of a
plant like stems, leaves and root etc., give rise to new ones, it is.called
vegetative propagation.
Q.3. Explain what you understand by
sexual reproduction.
Ans.Sexual reproduction means involvement of two parents in
the process of reproduction. It is found mainly in higher plants where male
gamete and female gamete fuse to form a zygote. These zygotes develop into
individuals which are not identical. Offsprings inherit the characteristics of
both the parents. In sexual reproduction both parents survive after the process
of reproduction.
Q.4. State the main difference
between asexual and sexual reproduction.
Ans.
Ans.
Q.6.Explain the difference between self-pollination and cross-pollination
Ans.
Ans.When the pollen grain reaches the stigma of a same
species flower, it starts
growing out into the pollen tube of the stigma. This tube
continues to grow inside the style till it reaches the ovule. Male cells are
released into the ovule for the fertilization with the female egg cell and thus
the zygote is formed. After this process of fertilization, the ovary develops
into fruit and ovule into seeds.
Q.8.Describe the various ways by
which seeds are dispersed.
Ans. Following are the ways in which the seeds are
dispersed:
(i) Some light seeds like that of madar, which are hairy,
dry and small are carried away by the wind to different places.
(ii) Spiny seeds and fruits like that of xanthium and
urena, stick to the clothes of passers by and animals. These seeds are carried
away by these agents to different places.
(iii) In some plants having heavy seeds like that of
coconut, water acts as the dispersing agents.
(iv) Some seeds are dispersed with the fruit burst like in
case of balsam and castor.
Q.9.Match items in Column I with those in Column II
Q.10. Tick (%/) the correct answer:
(a) The reproductive part of a plant is the
(i) leaf (ii) stem (iii) root (iv) flower(√)
(b) The process of fusion of the male and the female
gametes is called
(i) fertilisation (√) (ii) pollination (iii) reproduction
(iv) seed formation
c) Mature ovary forms the
(i) seed (ii) stamen (iii) pistil (iv) fruit(√)
(d) A spore producing plant is
(i) rose (ii) bread mould (√) (iii) potato (iv) ginger
(e) Bryophyllum can be reproduced by its
(i) stem (ii) leaves (√) (iii) roots (iv) flower
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Mrfarooqui