Reproduction in Plants | Science | Chapter 12 | Class 7th | Questions and Answers |

JANDKNCERT | Science | Class 7th |

Reproduction in Plants | Science | Chapter 12 | Class 7th | Questions, and Answers |

 

Chapter 12: Reproduction in Plants

EXERCISE

(I) Multiple choice questions – Write correct answers from the given choices.

1. The common method of reproduction in bacteria is

(a) Budding

(b) Fragmentation

(c) Binary fission

(d) All the above

Ans. (c) Binary fission

 

2. Budding is commonly seen in

(a) Yeast

(b) Grasses

(c) Amoeba

(d) Bryophyllum

Ans. (a) Yeast

 

3. Reproduction or propagation by the stem is common in

(a) Rose

(b) Potato

(c) Sweet potato

(d) Bryophyllum

Ans. (b) Potato

 

4. Unisexual flowers are found in

(a) Mulberry

(b) Mustard

(c) Pea

(d) Sunflower

Ans. (a) Mulberry

 

5. A seed consists of

(a) Embryo

(b) Seed coat and cotyledons

(c) Embryo and seed coat

(d) Seed coat and endosperm

Ans. (c) Embryo and seed coat

 

6. An embryo of a seed consists of

(a) Plumule

(b) Radicle, plumule, and cotyledons

(c) Plumule and radicle

(d) Radicle and cotyledons

Ans. (c) Plumule and radicle

 

(II) Fill in the blanks:

(a) Budding is a kind of _______ reproduction.

(b) The amount of cytoplasm in the parent cell is ________ than the amount in the bud.

(c) Yeast cells reproduce by ________.

(d) Binary fission produces cells of ________ size.

(e) Budding produces cells of ________ size.

(f) Fungi, ferns, and mosses reproduced by ________.

(g) Male sex cells in plants are called ________.

(h) The two kinds of pollination are _______ and _______.

Ans.

(a) Budding is a kind of asexual reproduction.

(b) The amount of cytoplasm in the parent cell is more than the amount in the bud.

(c) Yeast cells reproduce by budding.

(d) Binary fission produces cells of equal size.

(e) Budding produces cells of unequal size.

(f) Fungi, ferns, and mosses reproduced by spores.

(g) Male sex cells in plants are called pollen grains.

(h) The two kinds of pollination are self-pollination and cross-pollination.

 

 

(III) State whether the statements given below are true or false:

(a) Asexual reproduction is more common than sexual reproduction. True

(b) Producing life is called respiration. False

(c) Bacteria and yeast reproduce by asexual reproduction. False

(d) Reproduction by spores is a method of asexual reproduction. True

(e) A potato tuber is really an underground stem. True

(f) A whole new plant can grow from the eye of a tuber. True

(g) Cutting and grafting are natural means of reproduction. False

(h) Most organisms have the capacity of regeneration in some or other ways. True

(i) Stamens make egg cells. False

(j) A fertilized egg becomes a seed. True

(k) The flower which possesses stamens and pistils are called unisexual. False

(l) Insect pollinated flowers are brightly coloured. True

 

(IV) Differentiate between the following:

1. Asexual reproduction and sexual reproduction.

Ans.

 

Sexual Reproduction	Asexual Reproduction
1. It occurs in all types of animals. 2. It involves two individuals. 3. There is the formation of gametes. 4. Fertilization takes place. 5. Variations are produced as it contributes two individuals.	1. It occurs in invertebrates and lower chordates. 2. It involves only one individual. 3. No gametes are formed. 4. There is no fertilization. 5. No variations are produced as it contributes only to a single individual.

 

2. Binary fission and budding.

Ans.

Binary Fission	Budding
1. Organism divides into two equal sized cells after a transverse wall.   2. After binary fission equal-sized cells are formed. 3. It occurs mostly in bacteria.	1. A small outgrowth (bud) appears on the parent cell. This bud develops into a new organism. 2. An organism with a small size is formed. 3. It occurs in yeast cells.

 

3. Self-pollination and cross-pollination.

Ans.

Self-Pollination	Cross-Pollination
1. It occurs in the same flower.   2. It requires little production of pollen grains. 3. Varieties produced by this, are weak. 4. It does not require pollinating agents.	1. It occurs in different flowers either in the same or different plants. 2. It requires more production of pollen grains. 3. Varieties produced by this, are strong. 4. It requires some pollinating agents for pollination.

 

4. Insect pollination flowers and wind pollination flowers.

Ans.

Insect Pollinated Flowers	Wind Pollinated Flowers
1. Insect pollinated flowers are brightly coloured so that they can attract insects. 2. They produce rough spiny and sticky pollen grains that easily stick on the hairy parts of visiting insects.	1. They are small and rarely coloured.   2. They produce smooth-surfaced pollen grains in abundance.

 

5. Zygote and embryo

Ans. Zygote is formed by the fusion of two gametes, while as, An Embryo consists of plumule and radicle it develops into a new plant.

 

(V) Find the odd one out, giving reasons:

1. Gamete, budding, fragmentation, regeneration

Ans. Gamete, because it is a reproductive cell, while as budding, fragmentation, and regeneration, are asexual reproduction processes.

 

2. Cutting, grafting, layering, binary fission

Ans. Binary fission, because asexual reproduction takes place naturally in unicellular organisms, while as, cutting, grafting, and layering are artificial methods of vegetative propagation.

 

3. Ovary, stigma, style, pollen grain

Ans. Pollen grain, because it is a male gamete in flowers, while as, ovary, stigma, and style, are parts of the female reproductive system.

 

(VI) Name the following:

1. Part of the flower where ovule is found.

Ans. Ovule is found in the ovary of a flower. The ovary is a female reproductive part present in the carpel of the flower.

 

3. Three agents of pollination.

Ans. Wind, water, and insects are the three agents of pollination.

 

4. The place where fertilization occurs in the flowering plant.

Ans. Fertilization occurs in the ovary with a female gamete inside an ovule.

 

Also, Read: Science and Technology

(VII) Mention the functions of the following:

1. Flower

Ans. It is the structure in the flowering plant that bears the organs for sexual reproduction.

 

2. Anther

Ans. It produces various pollen grains.

 

3. Ovary

Ans. It produces ovules.

 

4. Stigma

Ans. It produces some sticky substances on which pollen grains stick during pollination.

 

5. Seed dispersal

Ans. Seed dispersal helps plants to prevent overcrowding, avoid the competition of water, mineral, and sunlight, and spread to a new habitat.

 

(VIII) Answer the following questions:

Q1. Why is reproduction necessary for living organisms?

Ans. Reproduction is necessary for living organisms because it maintains the genetic continuity among species and it allows to increase in the total number of species.

 

Q2. How much of the parent’s nuclear material does each daughter cell get during reproduction by binary fission?

Ans. During reproduction y binary fission, each daughter cell gets an equal part of the nuclear material from the parent cell.

 

Q3. What kind of reproduction is binary fission?

Ans. Binary fission is an asexual form of reproduction. It occurs mostly in unicellular organisms in plants.

 

Q4. How many parents take part in binary fission?

Ans. Only one parent takes part in binary fission.

 

Q5. Describe the various methods of asexual reproduction.

Ans. Following are the various methods of asexual reproduction:

1. Binary and multiple fission: It is common among plants in unicellular p organisms like an amoeba.

2. Fragmentation: It occurs in filamentous organisms, such as spirogyra (algae). In these organisms, filaments are broken into two or more fragments.

3. Spore formation: Spore formation is a common method of reproduction in non-flowering plants, such as bacteria, fungi, fern, etc.

4. Budding: It occurs in yeasts. A bud is formed on the body of an organism.

5. Regeneration: The ability, of living things, to repair themselves or grow lost parts is called regeneration. It is mostly, common in plants.

6. Vegetative reproduction: It is common in plants where vegetative parts, namely, the root stem or leaf give rise to new parts.

 

Q6. Describe the various methods of vegetative reproduction.

Ans. Following are the methods of vegetative reproduction:

1. Vegetative propagation by roots: In this method swollen roots like sweet potato, dahlia or asparagus are buried in the soil to give rise to the new plant.

2. Vegetative propagation by stems: Stem is buried in the soil to give rise to new plants.

3. Vegetative propagation by leaves: Detachment of plantlets develop into new independent plants.

 

Q7. Mention two characteristic features of wind-pollinated flowers.

Ans.

(i) Wind pollinated flowers are small and rarely coloured.

(ii) They produce smooth-surfaced pollen grains in abundance.

 

Q8. Mention two features of insect-pollinated flowers.

Ans.

(i) Insect pollinated flowers are brightly coloured so that they can attract insects.

(ii) They produce rough, spiny, and sticky pollen grains.

 

Q9. Describe the various steps leading to the formation of seeds in plants.

Ans. Following steps are involved in the formation of seed:

(i) The flower loses its bright colour.

(ii) The sepals, petals, and stamens fall off.

(iii) The ovary increases in size and becomes the fruit. The fruit thus is the ripened ovary.

(iv) The ovary wall becomes the fruit wall.

(v) Inside the ovary, the ovules develop to form the seeds.

 

Q10. Describe the various ways by which seeds are dispersed.

Ans. Seeds are dispersed by the ways of wind, water, and animals. Winds take seeds from one place to another. Some seeds and fruits fall in the water and are carried to other places. Some seeds are stuck to animals and are carried out by them to other places.

 

(IX) Spell the missing word. Fill in the missing letters to spell the terms that fit the definition:

1. ___ t ___ g ___ a                 (a) Top part of pistil

2. ___ g ___                             (b) Female gamete

3. ___ m ___ r ___ o                (c) Baby plant

4. ___ u ___ d ___ n ___         (d) Method of asexual reproduction

Ans.

1. Stigma             (a) Top part of the pistil

2. Egg                  (b) Female gamete

3. Embryo           (c) Baby plant

4. Budding          (d) Method of asexual reproduction

 

(X) Spot the odd term. In each of the following set, one term does not belong to the set. Circle that term.

1. Sexual reproduction          asexual reproduction            one parent

2. Sexual reproduction          asexual reproduction            two-parent

3. Binary fission                    bacteria                                  yeast

4. Binary fission                    budding                                 yeast

5. Stamen                               anther                                     style

Ans.

1. Sexual reproduction

2. Asexual reproduction

3. Yeast

4. Binary fission

5. Style