7th Std Science 2 Plants : Structure and Function l Question and Answer

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Science Studies -  7th Standard

2. Plants : Structure and Function

1. Give examples of 3 plants that have :

(a) spiny fruits

Ans: Star Apple, Jackfruit, Castor, Sweet berries

 

(b) spiny stem

 Ans: Cactus, Bamboo, Silk floss tree

(c) red flowers

Ans: Rose, Daisy, Marigold

 

(d) yellow flowers

Ans: Sunflower, Golden shower tree, Rose

 

(e) leaves which close at night

Ans: Mimosa, Gulmohar, Amla

 

(f) single-seeded fruits

Ans: Mango, Grapes, Date

 

(g) many-seeded fruits

Ans: Papaya, Jackfruit, Pomegranate

 

2. Observe any one flower and its various parts and describe it in your own words.

Ans: Various parts of flowers are described as follows:

1) Calyx : In the bud condition the petals are covered by leaf-like parts called sepals which are green in colour. They form the calyx.

2) Corolla : This is made up of colourful parts called petals. Its shape, colour and smell of the corolla of various flowers are different.

3) Androecium : This is the male reproductive part of the flower. It consists of stamens. Each stamen is made up of anther and filament.

4) Gynoecium : This is the female reproductive part of the flower. This is made up of carpels. A carpel consists of stigma, style and ovary.

3. What are the similarities and differences between?

(a) jowar and moong

Ans:

Similarities: Jowar and Moong both are angiosperms.

 

Difference Between:

Jowar	Moong
It has fibrous roots.	It has tap roots.
It is monocotyledonous seed.	It is dicotyledonous seed.

 

(b) onion and coriander

Ans:

Similarities: onion and coriander both are use for cooking

 

Difference Between:

onion	coriander
It has fibrous roots.	It has tap roots but
It is monocotyledonous seed.	It is dicotyledonous seed.

 

(c) leaves of banana and mango

Ans:

Similarities: Leaves of banana and mango have medicinal use also

 

Difference Between:

leaves of banana	leaves of mango
It has parallel venation	It ha reticulated venation
It is large in size	It is small in size

(d) coconut tree and jowar stalk plant

Ans:

Similarities: coconut tree and jowar stalk plant both are auto trophic & both are monocotyledonous plant.

 

Difference Between:

coconut tree	jowar stalk plant
Coconut tree is tall	Jowar stalk plant is small
It has thick stem	It has thin stem

 

 

4. Explain the following images in your own words.

Ans:

Diagram A: In diagram A it is maize seed. It is a monocotyledonous seed. It does not divide into two equal parts. It has fibrous root system.

Diagram B: In diagram B it is bean seed. It is a dicotyledonous seed and it divide in to two equal parts. It has tap root system.

 

5. Describe the functions of various parts of a plant.

Ans: The roots, stem, leaves, flowers, fruits etc are different parts of plant. There functions are as follows:

Root: i) Anchoring and supporting the plant

ii) absorption of water and minerals

iii) Aerial roots absorb moisture from air, stilt roots give additional support, Runner roots help in vegetative propagation, Breathing roots are help to breath for plant, some underground roots store food materials etc.

 

Stem: i) To hold all the branches of the plant

ii) To perform function of photosynthesis as in cactus

iii) To transport water and food

iv) Stem perform functions such as food storage, reproduction, support etc.

 

Leaves: i) Production of food by performing photosynthesis

ii) Transpiration means giving out excess of water

iii) Leaves also perform functions like reproduction, food storage, support etc.

 

Flower: Reproduction

 

Fruits: Protection of seed and storage of food materials.

 

6. Certain properties are mentioned below. Find a leaf corresponding to each property and describe those plants.

leaves with smooth surface:

Ans: Banana leaf has smooth surface. It is large in size. It has parallel venation.

 

leaves with rough surface:

Ans:Hibiscus leaf has rough surface. It has reticulate venation. It is small in size.

 

fleshy leaf:

Ans: Water hyacinth has fleshy, glossy and smooth leaves. They are green in colour.

 

spines on leaf:

Ans: Opuntia is a desert plant Leaf is thick, fleshy and having spines on it. It is also called Prickly pear

7. Find the plant parts.