Class-7 Science Chapter-12 Reproduction in Plants, Additional Exercises in line with NCERT book / CBSE Syllabus
Chapter 12
Reproduction
in Plant
Exercises from
textbook
Additional
Exercises
Activities/Projects
Additional Exercises
Choose the correct answer:
1- Flowers which contain both stamens and
pistil are called
a.
Bisexual
flowers (√)
b.
Unisexual
flowers
c.
Anthers
d.
zygote
2- Which of the following is not a
vegetative part?
a.
Root
b.
Stem
c.
Flower
(√)
d.
leaf
3- Which of the following is a single
celled organism?.
a.
Bryophyllum
b.
Fern
c.
Yeast
(√)
d.
Xanthium
e.
Cotton
plant
4- Seeds and fruits of plants are carried
away by:
a.
Wind
b.
Water
c.
Animals
d.
All
the above (√)
5- Transfer of pollen from the anther to
the stigma of a flower is called
a.
Pollination
(√)
b.
Fertilization
c.
Fragmentation
d.
Budding
6- If the pollen lands on the stigma of the
same flower it is called
a.
Pollination
b.
Cross-pollination
c.
Self-pollination
(√)
d.
Fertilization
Fill in the blanks with suitable words:
1- In asexual reproduction, plants can give
rise to new plants without seed.
2-
The cell which results after fusion of the
gametes is called zygote.
3-
The small bulb-like projection coming
out from the yeast cell is called a bud.
4-
The method of preparing compost help of red
worms is called vermicomposting.
5-
All kind of plastics give out harmful
gases, upon heating or burning which may cause problems including cancer.
Match the column:
A
|
B
|
Cutting
|
A
part of stem/branch at which leaf arises
|
Node
|
A short stem around
whihch immature overlapping leaves are folded.
|
Axil
|
A
piece of branch with a node
|
Bud
|
Point os attachment
of leaf at node.
|
Ans
A
|
B
|
Cutting
|
A
piece of branch with a node
|
Node
|
A
part of stem/branch at which leaf arises
|
Axil
|
Point os attachment
of leaf at node.
|
Bud
|
A short stem around
whihch immature overlapping leaves are folded.
|
State whether the following statements are True
or False:
1-
The zygote develops into an embryo. (True)
2-
Vegetative buds can not give rise to new plants. (False)
3-
Flowers perrform the function of reproduction
in plants. (True)
4-
Seeds germinate and form new plants (True)
5-
Seed dispersal is aided by wind, water and
animals. (True)
Give one word for the following:
(a)
The production of new individual from their
parents.
Reproduction
Reproduction
(b)
Mode of reproduction in which plants give rise
to new plants without seeds.
Asexual Reproduction
(c)
Slimy green patches found in ponds or in other
stagnetent water bodies.
Algae
(d)
The cell which results after fusion of the gamets.
Zygote
Encircle the Odd one:
1-
Fragmentation,
budding, spore formation, pollination,
vegetative propagation (method of asexual reproduction)
2-
Style,
stigma, anther,
ovule, ovary (Female reproductive parts)
3-
Corn,
papaya, palm, cucumber, mustard
(unisexual flower)
4-
Mustard,
rose, papaya,
petunia (bisexual flower)
Differentiate between
(a) Asexual Reproduction
and Sexual Reproduction
(b) Unisexual Flower and
Bisexual flower
(c) Self-pollination and
Cross-pollination
(a) Asexual Reproduction and Sexual
Reproduction
Asexual Reproduction
|
Sexual Reproduction
|
In
asexual reproduction, new plants are obtained without production of seeds or
spores.
|
In
sexual reproduction, new plants are obtained by production of seeds.
|
Plants
produced by these ways take less time to grow and bear flowers and fruits
earlier.
|
Plants
produced by this way, take more time to grow and bear flowers.
|
Plant
produced by this way is exact copy of the parent plant.
|
Plant
produced by sexual reproduction have characters of both the parents.
|
(b) Unisexual Flower and Bisexual
Flower
Unisexual Flower
|
Bisexual Flower
|
The
flowers which contain either only the pistil or only the stamens are called unisexual
flowers.
|
Flowers
which contain both stamens and pistil are bisexual flowers.
|
Corn, papaya
and cucumber have bisexual flowers.
|
Mustard,
rose and petunia have bisexual flowers.
|
(c) Self-pollination and
Cross-pollination
Self-pollination
|
Cross-pollination
|
If the
pollen lands on the stigma of the same flower, it is called self-pollination.
|
When the
pollen of a flower lands on the stigma of another flower of the same plant,
or that of a different plant of the same kind, it is called
cross-pollination.
|
Answer the following questions:
Q. What is reproduction?
Ans- The production of new individual from their parents is known as reproduction.
Q. What is reproduction?
Ans- The production of new individual from their parents is known as reproduction.
Q. What do you understand by vegetative and reproductive parts of a plant.
Ans- Most
plants have roots, stems and leaves. These are called the vegetative p arts of
a plant.
After
a certain period of growth, most plants bear flowers. Flowers perform the
function of reproduction in plants. Therefore flowers are the reproductive
parts of plants.
Q. Define vegetative propagation.
Q. Define vegetative propagation.
Ans- Vegetative propagation is a type of asexual
reproduction in which new plants are produced from roots, stems, leaves and
buds. Since reproduction is through the vegetative parts of the plant, it is
known as vegetative propagation.
Q. What is cutting?
Ans-
Cutting
is a piece of branch with a node. If we burry a cutting of rose or champa plant
in the soil and water it everyday, we will see roots and new leaves arising
from it.
Q. What do you mean by
vegetative buds?
Ans- A vegetative bud is a short stem around which immature overlapping leaves are folded. It is found at the point of attachment of the leaf at the node. Vegetative buds can give rise to new plants.
Ans- A vegetative bud is a short stem around which immature overlapping leaves are folded. It is found at the point of attachment of the leaf at the node. Vegetative buds can give rise to new plants.
Q.
Name any two plants in which root gives rise to new plants.
Ans-
Roots of sweet potato and dahlia give rise to new plants.
Q.
How does a cactus plant reproduce?
Ans-
Cactus plant reproduces when its parts get detached from the main plant body.
Each detached plant can grow into a new plant.
Q.
Expalin reproduction in brophyllum ( sprout leaf plant) plant?
Ans-
Bryophyllum had buds in the margins of leaves. If a leaf of thihs plant falls
on a moist soil, each bud can give rise to a new plant.
Q.
Explain reproduction in yeast with the help of diagram.
Ans-
Yeast
is a single celled organism. It reproduces with a small bulb-like projection
coming out of its body. The bud gradually grows and gets detached from the
parent cell and forms a new yeast cell. Sometimes another bud arises from the
bud forming a chain of buds. This process produces a large number of yeast
cells in a short time.
Q.
How does an algae multiply?
Ans-
When
water and nutrients are available algae grow and multiply rapidly by
fragmentation.
An
algae breaks up into two or more fragments. These fragments or pieces grow into
new individuals. This process continues and they cove a large area in a short period
of time.
Q.
What are spores? Explain reproduction through spores.
Ans-
Spores are asexual reproductive bodies. Each spore is covered by a hard protective coat to
withstand unfavourable conditions such as high temperature and low humidity, so
they can survive for a long time.
When
spores are released they keep floating in the air, as they are very light and
can cover long distances. Under favourable conditions, a spore germinates and
develops into a new individual.
Plants
like moss and ferns reproduce by means of spores.
Q.
What do you think will happen if all the seeds of a plant were to fall at the
same place and grow there?
Ans-
If all the seeds of a plant were to fall at the same place and grow there.
There would be severe ompetition for sunlight, water, minerals and space. As a
result the seeds would not grow into healthy plants.
Q.
How does seed dispersal occur? How is it beneficial for plants?
Ans-
Seed dispersal occurs via air, water and animals.
Seed
dispersal is beneficial for plants as;
(1) It prevents competition between the plants
and its own seedlings for sunlight, water and minerals.
(2)
It enables the plants to invade new habitats for wider distribution.
Give reason. Why?
Q. In
the nature same kind of plants grow at different places.
Ans- In
nature same kind of plants grow at different places because of seed dispersal.
Seeds get dispersed in a wider region through air, water or animals.
Exercises from Textbook
Fill
in the blanks:
(a)
Production
of new individuals from the vegetative parts of parent is called vegetative
propagation.
(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 air , water and animals.
Q.
Describe the different methods of asexual reproduction. Give examples.
Ans- Following are
different methods of asexual reproduction:
(1)
Vegetative
propagation- It is a type of asexual reproduction in which new plants are
produced from roots, stems, leaves and buds.
(a)
From Roots- The
roots of some plants give rise to new plants. Sweet potato and Dahlia are
examples.
(b)
From Stem (Cutting)
- Cutting
is a piece of branch with a node. For example money plant or rose can be grown
in a pot with the help of cutting.
(c)
From leaves-
Leaf
of Bryophyllum plant has buds in its margins. If a leaf falls on a moist soil,
each bud can give rise to a new plant.
(2)
Budding- In yeast, new organisms are produced by bud formation
from the parent organism. After attaining its full size, the bud gets detached
and forms a new independent organism.
An algae breaks up into two
or more fragments. These fragments or pieces grow into new individuals.
(4)
Spore formation-
The spores are asexual reproductive bodies. Each spore is
covered by a hard protective coat to withstand unfavourable conditions such
high temperature and low humidity so that they can survive for a long time.
Under the favourable conditions spores germinate and develop into new
organisms.
Q.
Explain what do you understand by sexual reproduction.
Ans- In sexual
reproduction a male and a female gamete fuse to form a zygote. The process of
fusion of male and female gamets is called as fertilization. The zygote
develops into an embryo, which further develops into a new individual.
Q. State the main difeerence between asexual and sexual reproduction.
Ans-
Asexual Reproduction
|
Sexual Reproduction
|
In
asexual reproduction, new plants are obtained without production of seeds or
spores.
|
In
sexual reproduction, new plants are obtained by production of seeds.
|
Plants
produced by these ways take less time to grow and bear flowers and fruits
earlier.
|
Plants
produced by this way, take more time to grow and bear flowers.
|
Plant
produced by this way is exact copy of the parent plant.
|
Plant
produced by sexual reproduction have characters of both the parents.
|
Q.
Sketch the reproductive parts of a flower.
Q. Explain the difference between self-pollination and cross-pollination.
Ans-
Self-pollination
|
Cross-pollination
|
If the
pollen lands on the stigma of the same flower, it is called self-pollination.
|
When the
pollen of a flower lands on the stigma of another flower of the same plant,
or that of a different plant of the same kind, it is called
cross-pollination.
|
Q.
How does the process of fertilization takes place in flowers?
Ans-
During
pollination, pollen grains reach to the stigma of pistil. A pollen tube starts
to grow from stigma, continues to the style and reaches to the ovule. When it
reaches the ovule, the male gametes are released and fuse with it to form
zygote. The ovule develops into seed and the ovary into fruit after
fertilization.
Q. Describe the various ways by which seeds are dispersed.
Ans- In nature, seeds are dispersed by the
agencies of air, water and animals.
Following are some of the ways of seed
dispersal.
(1) By Air- Air carries the seeds distant places
for dispersal.
a.
Seeds like drumsticks
and maple are winged, so can easily be carried by air.
b.
Seeds of grasses are
very light.
c.
Some seeds and fruits
hairy and can get blown off with wind to far away places.
(2) By water- Some seeds of fruits like coconut
have floating ability in the form of spongy or fibrous outer coat.
(3) By Animals- Spiny seeds with hooks get
attached to the bodies of animals and are carried to distant places. For
example Xanthium and Urena.
(4) Fruits burst with sudden jerk- Some seeds are
dispersed when the fruits burst with sudden jerks. The seeds are scattered far
from the parent plant. For example castor and balsam.
Match items in Column I with those in Column
II:
Column I
|
Column II
|
Bud
|
Maple
|
Eyes
|
Spirogyra
|
Fragmentation
|
Yeast
|
Wings
|
Bread mould
|
Spores
|
Potato
|
Cutting
|
Rose
|
Ans-
Column I
|
Column II
|
Bud
|
Yeast
|
Eyes
|
Potato
|
Fragmentation
|
Spirogyra
|
Wings
|
Maple
|
Spores
|
Bread mould
|
Cutting
|
Rose
|
Tick (√) the correct answer:
(a) The reproductive parts of a plant is the
a.
Leaf
b.
Stem
c.
Root
d.
Flower (√)
(b) The process of fusion of the male and female
gamets is called
a.
Fertilization (√)
b.
Pollination
c.
Reproduction
d.
Seed formation
(c) Mature ovary forms the
a.
Seed
b.
Stamen
c.
Pistil
d.
Fruit (√)
(d) A spore producing plant is
a.
Rose
b.
Bread mould (√)
c.
Potato
d.
Ginger
(e) Bryophyllum Cn reproduce by its
a.
Stem
b.
Leaves (√)
c.
Roots
d.
Flowers
Activities/Projects
1-
Make your own cactus garden by collecting pieces cut from
different kinds of cacti. Grow the variety in one single flat container of in
separate pots.
2-
Visit a fruit market and collect as many local fruits as
possible. If many fruits are not available, you can collect tomatoes and
cucumbers (these are fruits, though we use them as vegetables). Make drawings
of the different fruits. Spill the fruits and examine the seeds with in. Look
for any special characteristics in the fruits and their seeds. You can visit a
library also to learn about this.
3-
Think of ten different fruit-bearing plants. Remember that many
vegetables are also fruits of the plants. Discuss with your teacher, parents,
farmers, fruit growers and agricultural experts (if available nearby) and find
out the manner of their dispersal. Present your data in the form of the table
as shown below:
S.No.
|
Name
of fruit-bearing plant
|
Agent
through which seeds are dispersed
|
Part
of a seed which helps in dispersal
|
1.
|
|||
2.
|
|||
3.
|
4-
Suppose there is one member of a particular kind of organism in
a culture dish, which doubles itself in one hour though asexual reproduction.
Work out the number of members of that kind of organism, which will be present
in the culture dish after ten hours. Such a colony of individuals arising from
one parent is called a “clone”.
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