7th Std Science Term 1 Solution in English | Lesson.5 Reproduction and Modification in Plants

Lesson 5. Reproduction and Modification in Plants

Reproduction and Modification in Plants Book Back Solution 2021

Lesson 5. Reproduction and Modification in Plants

I . Choose the correct answer.

1. Vegetative propagation by leaves takes place in

  1. Bryophyllum
  2. Fungi
  3. Virus
  4. Bacteria

Ans : Bryophyllum

2. Asexual reproduction in yeast is

  1. Spore formation
  2. Fragmentation
  3. Pollination
  4. Budding

Ans : Budding

3. Reproductive part of a plant is

  1. Root
  2. Stem
  3. Leaf
  4. Flower

Ans : Flower

4. Pollinators are

  1. Wind
  2. Water
  3. Insect
  4. All the above

Ans : All the above

5. Climbing roots are seen in

  1. Betel
  2. Black pepper
  3. Both of them
  4. None of them

Ans : Both of them

II. Fill in the blanks:

1. The male reproductive part of a flower is _________________.

Ans : Androceium. 

2. __________________ is the basal swollen part of the Gynoecium.

Ans : Ovary

3. After fertilization the ovule becomes _______________ 

Ans : Seed

4. Breathing roots are seen in _________________ plants..

Ans : Avicennia

5. Onion and Garlic are example of _______________ .

Ans : Bulb

III. Match the following:

1. Petal Opuntia
2. Fern Chrysanthemum
3. Phylloclade Attracts insect
4. Hooks Spore
5. Sucker Bignonia
Ans : 1 – C, 2 – D, 3 – A, 4 – E, 5 – B

IV. True of False.

1. A complete flower has four whorls

Ans : True

2. The e transfer of pollen to the stigma is known as pollination.

Ans : True

3. Conical shaped root is carrot

Ans : True.

4. Ginger is an underground root.

Ans : False 

Cu. An : Ginger is an underground stem

5. Leaves of Aloe vera are fleshy and store water

Ans : True

V. Assertion and Reasoning types of Question

  1. Assertion is incorrect, Reasoning is correct.
  2. Assertion is incorrect, Reasoning is incorrect.
  3. Assertion is correct, Reasoning is correct.
  4. Assertion is correct, Reasoning is incorrect.

1. Assertion : Pollination and fertilization in flowers, produces fruits and seeds.

Reason : After fertilization the ovary becomes fruit and ovule becomes seed.

Answer : Assertion is correct, Reasoning is correct.

2. Assertion : The example of conical root is carrot. 

Reason : It is an adventitious root modification.

Answer : Assertion is correct, Reasoning is incorrect.

VI. Answer very briefly:

1. Write two types of reproduction in plants.

  • Sexual Reproduction – ex: Hibiscus
  • Asexual Reproduction – ex: Potato

2. What are the two important parts of a flower?

  • Androecium – Male Reproductive organ
  • Gynoecium – Female Reproduction organ

3. Define – pollination.

Transfer of pollen grains from the another to the sigma is called pollination.

4. What are the agents of pollination?

  • Wind
  • water
  • insects
  • birds
  • animals.

5. Give example for Corm and Tuber

a. Corm

Ex: Colocasia

b. Tuber

Ex: Potato

6. What is tendril?

In climbes, the leaf of plant is modified into elongated structure to help the plants to climb efficiently. Ex: Pison sativum (Peas)

7. What are thorns?

Leaves are reduced to spines, known as thorns. Ex: Opuntia.

VII. Answer very briefly:

1. Differentiate bisexual flower from unisexual flower?

Self pollination Cross pollination
1. Complete flower  Incomplete flower
2. Four whorls-calyx, corolla, stamen and pistil are present. Any of the four whorls is missing.

2. What is cross pollination?

Pollen grains are transferred from anther of one flower to the stigma of another flower of the same kind or different plant.

3. Write notes on phyllode.

In Acacia auriculiformis, petioles expand to form leaf like structure. They carry out the function of the leaf (photosynthesis).

VIII. Answer in details:

1. Write down a brief account on pollination

Transfer of pollen grains from the anther to the sigma is called pollination.

Types of pollination:

Artificial pollination :

When pollen grains are transferred artificially to the stigma of the flower.

Natural pollination:

When pollen grains are transferred naturally to the stigma of the flower. They are of two types.

  • Self pollination
  • Cross pollination
Self pollination Cross pollination
1. Pollen grains are transferred from the anther to the stigma of the same flower or to another flower of the same plant. Pollen grains are transferred from the anther of one flower to stigma of another flower of the same kind or different plant.
2. Plants do not need to produce pollen grains in a large quantity for self pollination. Plants need to produce pollen grains in larger quantities to increases the chance of pollination.
3. It does not produce changes in the characteristic of new plants. Cross pollination does introduce variations in characteristics of new plants.

2. Explain the underground stems.

In underground modified stem, Whole stem is buried under the ground. It has definite growth. There are four types of underground stems.

  1. Rhizome
  2. Corm
  3. Tuber
  4. Bulb

Rhizome:

  • It is an underground thick stem with nodes and internodes with scale leaves at the node.
  • It grows horizontally and has an irregular shape.
  • It has buds.
  • If gives rise to new stem and leaves.
  • ex. Ginger and Turmeric.

Corm:

  • This underground stem is round in shape and flat at top and bottom.
  • It is a condensed form of rhizome and bears one or more buds in the axis scales leaves.
  • Daughter plants arise from their buds.
  • ex. Colocasia

Tuber:

  • It is an enlarged, shaperical underground stem that stores food.
  • It has many dormant buds on its surface known as eyes.
  • If we plant a part of tuber with the bud, it grows into a new plant.
  • ex. Potato.

Bulb:

It is a condensed stem which is disc like and stores food in the fleshy leaves.

The bulb has two types of leaves:

Fleshy leaves

The upper part of the stem has a terminal bud and it is covered by many scaly leaves.

Scaly leaves

The inner fleshy leaves store food as seen in garlic and onion.

IX. Picture Based question.

i. Label the picture given below:

1. Stigma 2. Style 3. Ovary 4. Ovule
5. Petal 6. Anther 7. Filament 8. Sepal
9. Pistil 10. Stamen

ii. Identify the four plants shown in the following table Name the different modifications in each of them.

Name Modification
1. Garlic Underground stem – store food
2. Turnip Roots – for storage
3. Rose plant Leaves reduced to spines – for photosynthesis
4. Maize Still roots – Mechanical supports from nodes.


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