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Page No 164:

Question 1:

Vegetative propagation in Brophyllum (kalanchoe) takes place from the
(a) stem.
(b) leaf.
(c) root.
(d) node.

Answer:

b) leaf

Vegetative propagation in Bryophyllum (Kalanchoe) takes place from the leaf. The leaves of these plants have several buds at their margins that fall on the ground along with the leaves and develop into new tiny plants.

Page No 164:

Question 2:

The eyes in potato are equivalent to the
(a) stem.
(b) leaf.
(c) root.
(d) bud.

Answer:

(d) bud

The eyes in potato are equivalent to buds. When buried in soil, each of these buds develops into a new plant.

Page No 164:

Question 3:

Which of these is not true about asexual reproduction?
(a) maintains the quality of plants
(b) involves only one parent
(c) results in greater variety
(d) no special cells are required

Answer:

(c) Results in greater variety

Asexual reproduction is a mode of reproduction that does not involve any special cells. It requires only one parent and the individuals produced are identical to the parent plant. Asexual reproduction results in plants with less variation. Sexual reproduction, on the other hand, results in plants of a greater variety.

Page No 164:

Question 4:

Flowers which have either male or female parts present in them are called
(a) unisexual.
(b) bisexual.
(c) trisexual.
(d) male female flowers.

Answer:

(a) unisexual

Flowers that contain either male (stamen) or female (pistil) parts are known as unisexual flowers.



Page No 165:

Question 5:

Which of these features is not present in seeds and fruits dispersed by the wind?
(a) They have wings.
(b) They have hair on them.
(c) They have spines on them.
(d) They are light.

Answer:

(c) They have spines on them.

Seeds and fruits that get dispersed by the wind are usually small in size and light in weight. They may also have wings or hair-like structures on them. Seeds and fruits that have spines or hooks on them are dispersed by animals.

Page No 165:

Question 6:

Algae and mosses reproduce through
(a) stem.
(b) root.
(c) spores.
(d) buds.

Answer:

(c) spores

Algae and mosses reproduce through spores. Spores are asexual reproductive bodies that are protected inside special fruiting bodies to withstand unfavourable conditions.

Page No 165:

Question 7:

The transfer of pollen grains from the anther of one flower to the stigma of another flower on a different plant of same kind is called
(a) self pollination
(b) fertilisation
(c) fusion of gametes
(d) cross pollination.

Answer:

(d) cross-pollination

The pollination that takes place between the flowers of the same species on two different plants is known as cross-pollination.

Page No 165:

Question 8:

Which of these is a modification to save water?
(a) potato tuber
(b) cactus spine
(c) thorn
(d) rhizome

Answer:

(b) Cactus spine

Spines are the modified leaves that help cacti in conserving water.

Page No 165:

Question 9:

Which of these is not a modification for reproduction?
(a) potato tuber
(b) rhizome
(c) runner
(d) prop root

Answer:

(d) Prop root

Prop root is the root that arises from a stem. It penetrates the soil and helps in anchoring the plant to the ground. Potato tuber, rhizome and runner are the vegetative parts of plants that are modified for reproduction.

Page No 165:

Question 10:

Seeds are not dispersed by
(a) wind.
(b) water.
(c) snakes.
(d) birds.

Answer:

(c) snakes

Seeds are not dispersed by snakes.

Page No 165:

Question 11:

Fertilisation is the
(a) fusion of the sperm cell and the ovule.
(b) transfer of the sperm cell to the egg.
(c) fusion of the pollen and the egg.
(d) fusion of the sperm cell and the egg.

Answer:

(d) fusion of the sperm cell and the egg

Fertilisation is the fusion of the sperm cell with the egg in the ovule. A pollen grain contains the male cell called sperm cell.

Page No 165:

Question 12:

Which of these are agents of pollination?
(a) wind, water, frogs, insects
(b) water, insect, wind, birds
(c) water, wind, buffaloes, butterflies
(d) wind, water, cows, birds

Answer:

(b) Water, insect, wind and birds

Pollination is the process of transfer of pollens from the anther to the stigma. The main agents of pollination are wind, water, insects and birds.

Page No 165:

Question 13:

A plant which does not reproduce by spores is
(a) algae.
(b) moss
(c) neem.
(d) fern.

Answer:

(c) neem

Neem does not reproduce by spores. Its mode of reproduction is sexual, that is, by seed production.

Page No 165:

Question 14:

Which of the following fruits is dispersed by water?
(a) mango
(b) banana
(c) coconut
(d) groundnut

Answer:

(c) Coconut

Coconut is dispersed by water. It has a fibrous coating and some air space inside that help it to float.

Page No 165:

Question 15:

Reproduction is the process by which
(a) plants multiply.
(b) the species are maintained.
(c) they leave behind individuals.
(d) all the above

Answer:

(d) all the above

Reproduction is the process of producing individuals from their parents. They reproduce to maintain their number and ensure the continuance of their kind.

Page No 165:

Question 16:

Which of the following is not a property of sexual reproduction?
(a) fusion of sperm cell and the egg.
(b) Usually two parents are involved in the reproduction.
(c) one parent is involved
(d) produces greater variety

Answer:

(c) One parent is involved.

One parent is involved in asexual reproduction. Sexual reproduction involves two parents. It results in individuals that are neither identical to their parents nor identical to each other, thus resulting in greater diversity.

Page No 165:

Question 17:

Regeneration is a method by which organism can
(a) regenerate a cell.
(b) regenerate a lost part.
(c) regenerate a flower.
(d) grow into a new organism.

Answer:

(b) regenerate a lost part

Regeneration is the ability of the body of an organism to grow or replace a lost part. It is more common in plants than in animals.



Page No 166:

Question 18:

Mark these statements as true or false.
Correct and rewrite the false statements.
(a) In self pollination only one parent is involved.
(b) Cross pollination takes place between flowers of different types.
(c) Algae, mosses and ferns reproduce by producing seeds.
(d) In grafting, stock is grafted on scion.
(e) Tissue culture is one of the methods of artificial vegetative propagation.
(f) Spriogyra reproduces by fragmentation.
(g) Regeneration is more common in animals.
(h) Cross pollination results in greater variety in plants.
(i) Dispersal of seeds is necessary for better survival of plants.
(j) Asexual reproduction involves two parents.

Answer:

(a) True

(b) False
Cross-pollination takes place between flowers of the same species on two different plants.

(c) False
Algae, mosses and ferns reproduce by spore formation.

(d) False
In grafting, scion is grafted on stock.

(e) True

(f) True

(g) False
Regeneration is more common in plants than in animals.

(h) True

(i) True

(j) False
Sexual reproduction involves two parents.

Page No 166:

Question 19:

Why are flowers important to plants?

Answer:

Flower is the main reproductive part of a plant; it contains sexual organs called stamens and carpels. These organs are involved in the sexual reproduction of plants. Hence, flowers are important to plants.

Page No 166:

Question 20:

Differentiate between the following:
(a) asexual and sexual reproduction
(b) self and cross pollination
(c) wind-pollinated flowers and insect pollinated flowers

Answer:

(a) Difference between asexual and sexual reproduction
 

Asexual Reproduction Sexual Reproduction
It requires only one parent.     It requires two parents.
The newly developed plants are identical to the parent and to each other.   The newly developed plants are not identical to the parents.
Special reproductive cells are not required in asexual reproduction. Flower is the main reproductive part that contains the special cells required for sexual reproduction.
Examples are potato, rose and jasmine.   Examples are flowering plants like neem, mango and papaya.

(b) Difference between self-pollination and cross-pollination
 
Self-Pollination Cross-Pollination
It involves the transfer of pollen grains within the same flower or between different flowers of the same plant. It involves the transfer of pollen grains between the flowers of the same species on two different plants.

(c) Difference between wind-pollinated flowers and insect-pollinated flowers
 
Wind-Pollinated Flowers Insect-Pollinated Flowers
Flowers are usually small and are not brightly coloured. Flowers are usually large, coloured and showy, for example, orchids.
Flowers are not scented, as it is not required. Flowers are strongly scented to attract insects that are active during the night, for example, jasmine.
Flowers do not contain nectar.     Flowers usually contain nectar to attract insects.
Pollen grains are small and dry and light in weight so that they can be easily carried away by the wind. Pollens are often sticky or spiky to stick to insects.
They produce huge quantities of pollens to allow wastage when carried by wind to another flower. They produce moderate quantity of pollens, as it involves less wastage than wind pollination.
Stigmas are feathery or net-like to catch the drifting pollens. Stigmas are usually sticky so that the pollens brought by insects easily stick to them.

Page No 166:

Question 21:

Find the odd one out from the following groups giving reasons.
(a) mango, banana, guava, coconut
(b) wheat, rice, bean, maize
(c) papaya, marigold, lily, rose

Answer:

(a) Banana
Banana is a seedless fruit that can be grown asexually, while mango, guava and coconut reproduce sexually by the production of seeds.

(b) Bean
Bean seeds have two cotyledons, while wheat, rice and maize have one cotyledon.

(c) Papaya
Papaya is a fruit, while marigold, lily and rose are flowers.

Page No 166:

Question 22:

Write short notes on the following:
(a) tissue culture
(b) grafting
(c) the advantages of vegetative reproduction

Answer:

(a) Tissue culture:

Tissue culture is a process of developing a complete plant from a part of a plant. It is based on the tissue and cell culture technique. Here, a part of a tissue taken from the growing tip of a stem is transferred to a flask, which has a suitable nutrient medium and hormones under aseptic conditions. The tissue develops into a mass of fast-growing undifferentiated cells. The tissue is then transferred to another medium where cell gets differentiated into plantlets. The plantlets are then transplanted in pots or soil and raised to maturity.
The technique is commercially used for the production of orchids, chrysanthemum, dahlia and other ornamental plants.

(b) Grafting:

Grafting is a method where the stem of a desired plant is cut and inserted in the root system of another plant. The portion of the stem that is grafted on is called scion, while the plant onto which grafting is done is called stock.
Examples include a rose plant with a well-developed root system but poorly formed flowers and a rose plant with beautiful flowers but a poor root system. Plant growers can graft these parts of plants and obtain a plant with a well-developed root system and beautiful flowers.

(c) Advantages of vegetative propagation:

  • It is a method of propagation for seedless plants such as sugarcane, potato and rose.
  • The plants produced are similar to the parent plant. They are exact copies of the parent plant and each other.
  • A large number of offspring can be produced.
  • New plant varieties can be produced through grafting.
  • Disease-free plants can be propagated by this method.

Page No 166:

Question 23:

Name the agents of pollination.

Answer:

Insects, water, birds and wind are the agents of pollination.

Page No 166:

Question 24:

What is the advantage of cross pollination over self pollination?

Answer:

Cross-pollination is defined as the pollination that takes place between the flowers of the same species on two different plants. Unlike self-pollination, cross-pollination involves mixing of the characteristics of two parents, which, in turn, results in a greater variety of individuals produced.

Page No 166:

Question 25:

You are given diagrams of
A. section through bulb of onion and
B. ginger

Answer the questions that follow.
(a) Name the modes of reproduction in both A and B.
(b) List one similarity and one difference between them.
(c) Give two advantages of their respective modes of reproduction.
figure

Answer:

(a) The mode of reproduction in A and B is vegetative propagation by stem. Vegetative propagation is the mode of asexual reproduction in which new plants are obtained from the vegetative parts of a plant. Onion reproduces vegetatively through the bulb and ginger reproduces through the rhizome.

(b) Similarity: Both of these are modified stems situated below the surface of the soil.
    Difference: Onion reproduces vegetatively through the bulb, while ginger reproduces vegetatively through the rhizome.

(c) Advantages of vegetative reproduction:
(i) It is a natural method of propagation. Characters of the parent plants are preserved.
(ii) It is an easy and cheap method of propagation.

Page No 166:

Question 26:

Draw a neat diagram of a section of a flower, naming and labelling parts showing the following functions.
(a) landing place for pollen grains
(b) contains eggs
(c) male part that produces pollen
(d) grows into a fruit
(e) protects flower in the bud state
(f) brightly coloured part that attracts insects

Answer:

(a) Landing place for pollen grains - Stigma

(b) Contains eggs - Ovule

(c) Male part that produces pollen - Anther

(d) Grows into a fruit - Ovary

(e) Protects flower in the bud state - Sepal

(f) Brightly coloured part that attracts insects - Petals

Page No 166:

Question 27:

Fill in the blanks.
(a) Fertilisation is the fusion of the _________________with the _________________.
(b) Ovary matures to form the ___________________.
(c) Seed leaves are called __________________.
(d) Night blooming flowers are usually ________________ and _______________.
(e) Seed dispersed by water are _________________ and have a _______________ outer layer.

Answer:

(a) Fertilisation is the fusion of the sperm cell with the egg.
(b) Ovary matures to form the fruit.
(c) Seed leaves are called cotyledons.
(d) Night blooming flowers are usually white and strongly scented.
(e) Seed dispersed by water are lighter and have a waterproof outer layer.

Page No 166:

Question 28:

Arrange the following events in the sequence in which they occur.
Development of pollen; development of pollen tube; fertilisation; formation of flower bud; formation of seed; opening of flower; development of ovary; pollination

Answer:

Formation of flower bud → development of pollen → development of ovary → opening of flower → pollination → development of pollen tube → fertilisation



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