Chapter 1
The Leaf
Class 6 - Concise Biology Selina
Multiple Choice Questions
Question 1
Identify the plant which has compound leaves:
1. Banana
2. Banyan
3. Mango
4. Rose
Answer
Rose
Reason — Rose leaf is a compound leaf with incisions upto midrib.
Question 2
Which one of the following is not an insectivorous plant:
1. Pitcher plant
2. Venus flytrap
3. Bladderwort
4. Cactus
Answer
Cactus
Reason — Cactus has modified leaves into spines due to which it does not trap insects.
Question 3
This leaf shows parallel venation
1. Banana
2. Mango
3. Banyan
4. Guava
Answer
Banana
Reason — In Banana leaves, veins runs parallel to each other.
Question 4
The point on the stem from where the leaf arises is :
1. Petiole
2. Lamina
3. Node
4. Trunk
Answer
Node
Reason — The points on the stem from where the leaves and branches originate are called
nodes.
Question 5
Which one of the following is essential for photosynthesis :
1. Carbon dioxide
2. Nitrogen
3. Oxygen
4. Soil
Answer
Carbon Dioxide
Reason — Out of the given options, Carbon dioxide is needed for photosynthesis.
Short Answer Questions
Question 1
Name the following:
1. The part of the plant which grows under the ground.
2. The part of the plant which grows above the soil.
3. The wide flat portion of the leaf.
Answer
1. Root
2. Shoot
3. Lamina / Leaf Blade
Question 2
What are the four functions of roots?
Answer
The main four functions of the roots are as follows:
1. It helps to anchor the plant firmly to the soil.
2. It absorbs water and minerals from the soil for the growth of the entire plant.
3. It transports the absorbed water and minerals to the shoot system.
4. It binds the soil together so that it does not get washed away during rain or blown
away by wind.
Question 3
Mention the functions of the following:
1. Spines
2. Tendril
3. Scale leaves
Answer
1. Spines — Spines are modifications of leaves as a pointed structure that help to reduce
the loss of water by transpiration.
2. Tendril — Incase of certain weak-stemmed plants, leaves or leaflets are modified
into wiry, coiled structures called tendrils. They coil around the object they touch and
support the plant to climb up.
3. Scale Leaves — Leaves modified as thick and fleshy or thin and dry are called Scale
Leaves. Their function is to store food and protect the buds.
Question 4
Define venation. What are the different types of venation found in the leaves?
Answer
Arrangement of veins in the lamina is called venation. It is mainly of two types
1. Reticulate Venation — In this type of venation, veins and veinlets are irregularly
distributed in the lamina, forming a network. Example - Mango, Peepal, etc.
2. Parallel Venation — In this type of venation, veins run parallel to each other.
Example - Banana, Maize, etc.
Question 5
Describe the modifications of leaf in any one insectivorous plant?
Answer
In Venus Flytrap, the leaves have long pointed hairs. It is divided into two parts having
midrib in between like a hinge. When an insect visits the leaf, it closes its two parts and traps
the insect. The insect is then digested by digestive juices secreted by the plant.
Question 6
Write the two main functions of leaves?
Answer
Two main functions of the leaves are:
1. Photosynthesis.
2. Transpiration.
Question 7
Define:
1. Photosynthesis
2. Transpiration
Answer
Photosynthesis — Photosynthesis is the process by which a plant leaf prepares own food
from water and carbon dioxide in the presence of chlorophyll and sunlight.
Transpiration — Transpiration is the process by which water is lost in the form of water
vapour by evaporation from the surface of leaves and other aerial parts of a plant.
Long Answer Questions
Question 1(i)
Giving examples, differentiate between Tap root and Fibrous root
Answer
Differences between Tap Root and Fibrous Root:
Tap root Fibrous root
There is one large, thick main root. There is a cluster of root of the same thickness.
Penetrates deeply into the soil. Does not penetrate deeply, is shallow.
Tap roots are found in dicot plants. Fibrous roots are found in monocot plants.
Example — Gram, Pea. Example — Maize, Grass.
Question 1(ii)
Giving examples, differentiate between Simple leaf and Compound Leaf
Answer
Differences between Simple leaf and Compound leaf:
Simple leaf Compound leaf
Lamina is divided into smaller uni
Lamina is undivided and is a single piece.
leaflets.
Marginal incisions, if present, do not reach upto the midrib or
Incisions reach upto the midrib or
petiole.
Example — Mango, Banana, Banyan, etc. Example — Rose, Neem, Clover,
Question 1(iii)
Giving examples, differentiate between Parallel venation and Reticulate Venation
Answer
Differences between Parallel venation and Reticulate venation:
Parallel venation Reticulate venation
Veins and veinlets are irregularly distributed in the lamina f
Veins run parallel to each other.
network.
Parallel venation is found in monocot
Reticulate venation is found in dicot plants.
plants.
Example — Banana, Maize. Example — Peepal, Mango.
Question 2
What is the modification seen in Bryophyllum? Explain.
Answer
Modification seen in bryophyllum are:
1. Bryophyllum is a plant whose leaves produce adventitious buds in their margin.
2. The adventitious buds grow into new plants when they fall off from the parent plant.
Question 3
What purpose is served by the spines borne on the leaves of cactus ?
Answer
Cactus being a desert plant needs to conserve water. So, its leaves are modified into pointed
structures called as spines to reduce the loss of water by transpiration.
Question 4
Explain why leaf survival is so important to the plant ?
Answer
Leaf survival is so important to plants because:
1. The leaf makes food for the plants by photosynthesis.
2. The leaf gets rid of excess water from plants through transpiration.
3. The leaf carries out the process of respiration in plants.
4. The leaf helps in providing cooling effect to the plant through transpiration.
Question 5
Give an example of the following and draw generalized diagrams for the same:
(i) Simple leaf and compound leaf.
(ii) Parallel venation and reticulate venation.
Answer
(i) Banyan is an example of simple leaf while Rose is an example of compound leaf.
Below diagram shows simple and compound leaves:
(ii) Banana is an example of parallel venation while Peepal is an example of reticulate
venation.
Below diagram shows reticulate and parallel venation:
Question 6
Enlist some of the advantages of transpiration to green plants?
Answer
The two main advantages of transpiration to green plants are as follow:
1. Cooling effect — The water keeps on evaporating from the leaf surface during
transpiration. The heat required for evaporation of water is obtained from the plant
itself and thus, the plant cools itself when it is in hot environment.
2. Transpirational pull — The roots of the plant pull up more water from the soil to
make up for the water loss during transpiration. As a result, important mineral salts,
which is essential for the plant growth, are also brought along with the water from the
soil.
Question 7
Why do some plants have to trap insects?
Answer
Insectivorous plants trap insects because they grow in soil which is usually thin and is also
low in nutrients, so insectivorous plants eat insects to fullfil their nitrogen demand.
Question 8
Explain some of the modifications of leaves found in plants?
Answer
Modifications of leaves are as follows:
1. Leaf tendril — In case of certain weak-stemmed plants, leaves or leaflets are
modified into wiry, coiled structures called tendrils. They coil around the object they
touch and support the plant to climb up. E.g., Sweet Pea.
2. Leaf spines — In some plants, leaves are modified into pointed structures called
spines. Spines help to reduce water loss by transpiration. E.g., Cactus.
3. Scale leaves — In some plants like Onion and Ginger, thick and fleshy or thin and
dry scale leaves are present, respectively. Their function is to store food and protect
the buds.
Question 9
What is a tendril? Explain its use to the plants?
Answer
In case of certain weak-stemmed plants, leaves or leaflets are modified into wiry, coiled
structures called tendrils. They are sensitive to touch. As they touch any object, they coil
around it and support the plant to climb up. E.g., Sweet pea.
