Plants: Structure and Function - Standard 7 - General Science - Balbharati

Plants: Structure and Function

Exercise

Q.1 Give examples of 3 plants that have:

(a) spiny fruits: 1) Pineapple 2) Jackfruit 3) Kadam

(b) spiny stem: 1) Cactus 2) Aloe Vera 3) Joshua tree

(c) red flowers: 1) Hibiscus 2) Rose 3) Tulip

(d) yellow flowers: 1) Sunflower 2) Marigold 3) Flame Lily

(e) leaves which close at night: 1) Acacia 2) Mimosa 3) Tamarind

(f) single-seeded fruits: 1) Mango 2) Cashew 3) Jamun

(g) many-seeded fruits: 1) Chikoo 2) Guava 3) Pomegranate

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

Ans. 

Flowers may have a long or a short stalk called pedicel. One end of the pedicel is attached to the stem. The other end of the pedicel is expanded and swollen. It is called the receptacle. Petals and other parts of the flower are supported on the receptacle. Calyx, corolla, androecium, gynoecium are different parts of a flower.

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

Corolla: This is made up of colourful parts called petals. Observe the shape, colour and smell of the corolla of various flowers like the rose, chrysanthemum, hibiscus, mogara, kanher, tagar, etc.

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

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.

Jowar	Moong
Jowar is a monocot plant.	Moong is a dicot plant.
Jowar has fibrous roots.	Moong has tap root.
The leaves of Jowar show parallel venation.	The leaves of Moong show reticulate venation.

(b) onion and coriander

Onion	Coriander
Onion is a monocot plant.	Coriander is a dicot plant.
Onion has fibrous roots.	Coriander has tap root.
The leaves of onion show parallel venation.	The leaves of coriander show reticulate venation.

(c) Leaves of Banana and Mango

Leaves of Banana	Leaves of Mango
It has large and elongated oval shape.	It has smaller and narrow, lanceolate.
These are spirally arranged on the stem	These are alternately arranged on stem.
Leaves of banana show parallel venation.	The leaves of Moong show reticulate venation.

(d) Coconut tree and Jowar stalk plant

Coconut	Jowar Stalk Plant
It is a tall palm tree.	It is medium-sized grain plant.
Leaves are large and feathery.	Leaves are narrow and pointed.
It has woody trunk.	It has fibrous stalks.

4. Explain the following images in your own words.

Ans. The picture shows a seed and what it looks like on the inside. The seed has three parts: the outer covering called the seed coat, the cotyledon, and the embryo. The seed coat is tough and protects the delicate parts inside. The embryo is big and swollen because it contains food for the seed to grow.

Ans. The picture displays two types of seeds: monocot and dicot seeds. A monocot seed has only one cotyledon, known as the scutellum. Inside, it has a relatively small embryo that holds the endosperm, which serves as a source of nourishment for the seed.

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

Ans. Various parts of the plant have the following functions:

(1) Functions of the Roots:

a. Anchoring and supporting the plant.

b. Absorption of water and minerals.

c. Some roots have modifications for additional functions.

d. For example, aerial roots absorb moisture from the air, stilt-roots provide extra support, runners aid in vegetative propagation, breathing roots (pneumatophores) help plants breathe, and some underground roots store food materials.

(2) Functions of the Stems:

a. Supporting all the branches of the plant.

b. In some plants like cactus, they also perform photosynthesis.

c. Transporting water absorbed by the roots to all parts of the plant and transporting food prepared by the leaves to various plant parts.

d. Modified stems perform functions such as food storage, reproduction, support, etc.

(3) Functions of the Leaves:

a. Production of food by performing photosynthesis.

b. Transpiration, i.e. giving out excess water.

c. Modified leaves perform additional functions such as reproduction, food storage, support, etc.

(4) Functions of Flowers: Reproduction

(5) Functions of Fruits: Protection of seeds and storage of food materials.

(6) Functions of Seed: A new plant develops from it.

6. Certain properties are mentioned below. Find a leaf corresponding to each property and describe those plants. leaves with smooth surface, leaves with rough surface, fleshy leaf, spines on leaf.

Ans. 1. Leaves with smooth surface: Ficus religiosa, commonly known as the Peepal tree, has smooth-edged, broad, and heart-shaped leaves. These leaves are smooth to the touch and have a characteristic glossy green color.

2. Leaves with rough surface: Calotropis procera, also known as the Apple of Sodom or Akra, is with rough-textured, large, and oblong leaves. The leaves have a slightly rough and hairy surface.

3. Fleshy leaf: Bryophyllum pinnatum, commonly called the Air Plant or Patharchatta, has fleshy, succulent leaves. These leaves store water and appear thick and juicy.

4. Spines on leaf: Moringa oleifera, known as the Drumstick tree or Sahjan, has leaves with small spines along the leaf margins. These spines are not sharp but are noticeable on the leaf edges.

7. Find the plant parts. (with answers)

r	b	u	d	x	s	r	f
o	w	p	y	e	t	a	l
o	l	l	d	n	e	d	o
t	a	o	i	l	m	i	w
c	n	e	t	a	l	c	e
a	v	o	v	u	m	l	r
p	e	t	a	l	s	e	o
r	o	o	t	h	a	i	r